Grant's Atlas of Anatomy [14 ed.]
 2015042750, 9781469890685

Table of contents :
CHAPTER
Back.....................................................................
OverviewofVertebralColumn
CervicalSpine
CraniovertebralJoints
ThoracicSpine
LumbarSpine
LigamentsandIntervertebralDiscs
Bones,Joints,andLigamentsofPelvicGirdle
AnomaliesofVertebrae
MusclesofBack
SuboccipitalRegion
SpinalCordandMeninges
VertebralVenousPlexuses
ComponentsofSpinalNerves
DermatomesandMyotomes
AutonomicNerves
ImagingofVertebralColumn
CHAPTER
UpperLimb.......................................................
SystemicOverviewofUpperLimb
Bones
Nerves
Arteries
VeinsandLymphatics
MusculofascialCompartments
PectoralRegion
Axilla,AxillaryVessels,andBrachialPlexus
ScapularRegionandSupercialBack
ArmandRotatorCuff
JointsofShoulderRegion
ElbowRegion
ElbowJoint
AnteriorForearm
AnteriorWristandPalmofHand
PosteriorForearm
PosteriorWristandDorsumofHand
LateralWristandHand
CHAPTER
Thorax.............................................................
PectoralRegion
Breast
BonyThoraxandJoints
ThoracicWall
ThoracicContents
PleuralCavities
Mediastinum
LungsandPleura
BronchiandBronchopulmonarySegments
InnervationandLymphaticDrainageofLungs
ExternalHeart
CoronaryVessels
ConductionSystemofHeart
InternalHeartandValves
SuperiorMediastinumandGreatVessels
Diaphragm
PosteriorThorax
OverviewofAutonomicInnervation
OverviewofLymphaticDrainageofThorax
SectionalAnatomyandImaging
CHAPTER
Abdomen........................................................
Overview
AnterolateralAbdominalWall
InguinalRegion
Testis
PeritoneumandPeritonealCavity
DigestiveSystem
Stomach
Pancreas,Duodenum,andSpleen
Intestines
LiverandGallbladder
BiliaryDucts
PortalVenousSystem
PosteriorAbdominalViscera
Kidneys
PosterolateralAbdominalWall
Diaphragm
AbdominalAortaandInferiorVenaCava
AutonomicInnervation
LymphaticDrainage
SectionalAnatomyandImaging
CHAPTER
PelvisandPerineum......................................
PelvicGirdle
LigamentsofPelvicGirdle
FloorandWallsofPelvis
SacralandCoccygealPlexuses
PeritonealReectionsinPelvis
RectumandAnalCanal
OrgansofMalePelvis
VesselsofMalePelvis
LymphaticDrainageofMalePelvisandPerineum
InnervationofMalePelvicOrgans
OrgansofFemalePelvis
VesselsofFemalePelvis
LymphaticDrainageofFemalePelvisandPerineum
InnervationofFemalePelvicOrgans
SubperitonealRegionofPelvis
SurfaceAnatomyofPerineum
OverviewofMaleandFemalePerineum
MalePerineum
FemalePerineum
PelvicAngiography
CHAPTER
LowerLimb.....................................................
SystemicOverviewofLowerLimb
Bones
Nerves
BloodVessels
Lymphatics
MusculofascialCompartments
Retro-InguinalPassageandFemoralTriangle
AnteriorandMedialCompartmentsofThigh
LateralThigh
BonesandMuscleAttachmentsofThigh
GlutealRegionandPosteriorCompartmentofThigh
HipJoint
KneeRegion
KneeJoint
AnteriorandLateralCompartmentsofLeg,DorsumofFoot
PosteriorCompartmentofLeg
TibiobularJoints
SoleofFoot
Ankle,Subtalar,andFootJoints
ImagingandSectionalAnatomy
CHAPTER
Head.................................................................
Cranium
FaceandScalp
MeningesandMeningealSpaces
CranialBaseandCranialNerves
BloodSupplyofBrain
OrbitandEyeball
ParotidRegion
TemporalRegionandInfratemporalFossa
TemporomandibularJoint
Tongue
Palate
Teeth
Nose,ParanasalSinuses,andPterygopalatineFossa
Ear
LymphaticDrainageofHead
AutonomicInnervationofHead
ImagingofHead
Neuroanatomy:OverviewandVentricularSystem
Telencephalon(Cerebrum)andDiencephalon
BrainstemandCerebellum
ImagingofBrain
CHAPTER
Neck.................................................................
SubcutaneousStructuresandCervicalFascia
SkeletonofNeck
RegionsofNeck
LateralRegion(PosteriorTriangle)ofNeck
AnteriorRegion(AnteriorTriangle)ofNeck
NeurovascularStructuresofNeck
VisceralCompartmentofNeck
RootandPrevertebralRegionofNeck
SubmandibularRegionandFloorofMouth
Pharynx
IsthmusofFauces
Larynx
SectionalAnatomyandImagingofNeck
CHAPTER
CranialNerves................................................
OverviewofCranialNerves
CranialNerveNuclei
CranialNerveI:Olfactory
CranialNerveII:Optic
andAbducent
CranialNerveV:Trigeminal
CranialNerveVII:Facial
CranialNerveVIII:Vestibulocochlear
CranialNerveIX:Glossopharyngeal
CranialNerveX:Vagus
CranialNerveXI:SpinalAccessory
CranialNerveXII:Hypoglossal
SummaryofAutonomicGangliaofHead
SummaryofCranialNerveLesions
SectionalImagingofCranialNerves

Citation preview

ANNE M.R. AGUR, BSc(OT), MSc, Ph D Professor, Division of Anatom y, Dep artm ent of Surgery, Faculty of Medicine Division of Physical Medicine and Rehabilitation, Departm ent of Medicine Dep artm ent of Physical Therap y, Departm ent of Occupational Science and Occupational Therapy Division of Biom edical Com m unications, Institute of Medical Science Rehabilitation Sciences Institute, Graduate Dep artm ent of Dentistry University of Toronto Toronto, Ontario, Canada

ARTHUR F. DALLEY II, Ph D, FAAA Professor, Departm ent of Cell and Develop m ental Biology Adjunct Professor, Departm ent of Orthopaedic Surgery Vanderbilt University School of Medicine Adjunct Professor of Anatom y Belm ont University School of Physical Therap y Nashville, Tennessee

Acquisitions Editor: Crystal Taylor Product Developm ent Editor: Greg Nicholl Marketing Manager: Michael McMahon Production Project Manager: Bridgett Dougherty Design Coordinator: Holly McLaughlin Art Director: Jennifer Clem ents Artist/ Illustrator: Nick Woolridge, Nicole Clough, Marissa Webber Manufacturing Coordinator: Margie Orzech Prepress Vendor: Absolute Service, Inc. Fourteenth Edition Copyright © 2017 Wolters Kluwer. Copyright © 2013, 2009 Lippincott William s & Wilkins, a Wolters Kluwer business. Copyright © 2005, 1999 by Lippincott William s & Wilkins. Cop yright © 1991, 1983, 1978, 1972, 1962, 1956, 1951, 1947, 1943 by William s & Wilkins. A.M.R. Ag ur an d A.F. Dalle y: Thirteenth Edition, 2013; Twelfth Edition, 2009 A.M.R. Ag ur: Eleventh Edition, 2005; Tenth Edition, 1999; Ninth Edition, 1991 J.E. An d e rso n : Eighth Edition, 1983; Seventh Edition, 1978 J.C.B. Gran t : Sixth Edition, 1972; Fifth Edition, 1962; Fourth Edition, 1956; Third Edition, 1951; Second Edition, 1947; First Edition, 1943 All rights reserved. This book is protected b y cop yrig ht. No p art of this book m ay be rep roduced or transm itted in any form or b y any m eans, including as photocop ies or scanned -in or other electronic copies, or utilized by any inform ation storage and retrieval system without written p erm ission from the copyright owner, except for brief quotations em bodied in critical articles and reviews. Materials appearing in this book prepared by individuals as part of their of cial duties as U.S. governm ent em ployees are not covered by the above-m entioned copyright. To request perm ission, please contact Wolters Kluwer at Two Com m erce Square, 2001 Market Street, Philadelphia, PA 19103, via em ail at perm [email protected] , or via our website at lww.com (products and services). 987654321 Printed in China Lib rary o f Co n g re ss Cat alo g in g -in -Pub licat io n Dat a Nam es: Agur, A. M. R., author. | Dalley, Arthur F., II, author. Title: Grant’s atlas of anatom y / Anne M.R. Agur, Arthur F. Dalley II. Other titles: Atlas of anatom y Description: Fourteenth edition. | Philadelphia : Wolters Kluwer, [2017] | Includes bibliographical references and index. Identi ers: LCCN 2015042750 | ISBN 9781469890685 Subjects: | MESH: Anatom y, Regional—Atlases. Classi cation: LCC QM25 | NLM QS 17 | DDC 611.0022/ 2—dc23 LC record available at http:/ / lccn.loc.gov/ 2015042750 This work is provided “as is,” and the pub lisher d isclaim s any and all warranties, exp ress or im p lied, including any warranties as to accuracy, com p rehensiveness, or currency of the content of this work. This work is no substitute for individual patient assessm ent based on healthcare professionals’ exam ination of each p atient and consideration of, am ong other things, age, weight, gender, current or prior m edical conditions, m edication history, laboratory data, and other factors unique to the patient. The p ublisher does not provide m edical advice or guidance and this work is m erely a reference tool. Healthcare professionals, and not the publisher, are solely resp onsib le for the use of this work including all m edical judgm ents and for any resulting diagnosis and treatm ents. Given continuous, rap id advances in m edical science and health inform ation, independ ent professional veri cation of m edical diagnoses, indications, appropriate p harm aceutical selections and dosages, and treatm ent options should be m ade and healthcare professionals should consult a variety of sources. When p rescribing m edication, healthcare professionals are ad vised to consult the product inform ation sheet (the m anufacturer’s package insert) accom panying each drug to verify, am ong other things, conditions of use, warning s and sid e effects and id entify any changes in dosage schedule or contraind ications, particularly if the m edication to be adm inistered is new, infrequently used, or has a narrow therapeutic range. To the m axim um extent perm itted under applicab le law, no resp onsibility is assum ed by the p ublisher for any injury and/ or dam age to persons or property, as a m atter of products liability, negligence law or otherwise, or from any reference to or use by any p erson of this work. LWW.com

To m y husband Enno and to m y fam ily Kristina, Erik, and Amy for their support and encouragem ent ( A.M.R.A.)

To Muriel My bride, best friend, counselor, and mother of our sons; To my fam ily Tristan, Lana, Elijah, Finley, Sawyer and Dashiell, Denver, and Skyler and Sara With great appreciation for their support, humor, and patience ( A.F.D.)

And with sincere appreciation for the anatom ical donors Without whom our studies would not be possible

Dr. John Charles Boileau Grant 1886–1973 b y Dr. Carlt o n G. Sm it h , MD, Ph D ( 1 9 0 5 –2 0 0 3 ) Professor Em eritus, Division of Anatom y, Dep artm ent of Surgery Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada

Dr. J.C. Boilea u Gra nt in his of ce, McMurrich Building, University of Toronto, 1946. Through his textbooks, Dr. Gra nt ma de a n indelible impression on the tea ching of a na tomy throughout the world. (Courtesy of Dr. C. G. Smith.) The life of Dr. J.C. Boileau Grant has been likened to the course of the seventh cranial nerve as it passes out of the skull: com plicated but purposeful. 1 He was born in the parish of Lasswade in Edinburgh, Scotland, on February 6, 1886. Dr. Grant studied m edicine at the University of Edinburgh from 1903 to 1908. Here, his skill as a dissector in the laboratory of the renowned anatom ist, Dr. Daniel John Cunningham (1850–1909), earned him a num ber of awards. Following graduation, Dr. Grant was ap pointed the resident house of cer at the In rm ary in Whitehaven, Cum berland. From 1909 to 1911, Dr. Grant dem onstrated anatom y in the University of Edinburgh, followed by 2 years at the University of Durham , at Newcastle-on-Tyne in England, in the laboratory of Professor Robert Howden, editor of Gray’s Anatom y. With the outbreak of World War I in 1914, Dr. Grant joined the Royal Arm y Medical Corps and served with distinction. He was m entioned in disp atches in Septem ber 1916, received the Military Cross in Septem ber 1917 for “consp icuous gallantry and devotion

vi

to duty during attack,” and received a bar to the Military Cross in August 1918. 1 In October 1919, released from the Royal Arm y, he accepted the position of Professor of Anatom y at the University of Manitoba in Winnipeg, Canada. With the frontline m edical p ractitioner in m ind, he endeavored to “bring up a generation of surgeons who knew exactly what they were doing once an op eration had begun.” 1 Devoted to research and learning, Dr. Grant took interest in other p rojects, such as perform ing anthrop om etric studies of Indian tribes in northern Manitoba during the 1920s. In Winnipeg, Dr. Grant m et Catriona Christie, whom he m arried in 1922. Dr. Grant was known for his reliance on logic, analysis, and d eduction as opp osed to rote m em ory. While at the University of Manitoba, Dr. Grant began writing A Method of Anatom y, Descriptive and Deductive, which was p ublished in 1937.2 In 1930, Dr. Grant accepted the position of Chair of Anatom y at the University of Toronto. He stressed the value of a “clean” d issection, with the structures well de ned. This required the delicate touch of a sharp scalpel, and students soon learned that a dull tool was anathem a. Instructive dissections were m ade available in the Anatom y Museum , a m eans of student review on which Dr. Grant p laced a high priority. Illustrations of these actual dissections are included in Grant’s Atlas of Anatom y. The rst edition of the Atlas, p ublished in 1943, was the rst anatom ical atlas to be published in North Am erica. 3 Grant’s Dissector preceded the Atlas in 1940.4 Dr. Grant rem ained at the University of Toronto until his retirement in 1956. At that tim e, he becam e Curator of the Anatom y Museum in the University. He also served as Visiting Professor of Anatom y at the University of California at Los Angeles, where he taught for 10 years. Dr. Grant died in 1973 of cancer. Through his teaching m ethod, still p resented in the Grant’s textbooks, Dr. Grant’s life interest— hum an anatom y—lives on. In their eulogy, colleagues and friends Ross MacKenzie and J. S. Thom pson said, “Dr. Grant’s knowledge of anatom ical fact was encyclop edic, and he enjoyed nothing better than sharing his knowledge with others, whether they were junior students or senior staff. While som ewhat strict as a teacher, his quiet wit and boundless hum anity never failed to im press. He was, in the very nest sense, a scholar and a gentlem an.” 1

1

Robinson C. Canadian Medical Lives: J.C. Boileau Grant: Anatomist Extraordinary. Ontario, Canada: Associated Medical Services Inc/Fithzenry & Whiteside, 1993. 2

Grant JCB. A Method of Anatom y: Descriptive and Deductive. Baltim ore, MD: William s & Wilkins Co, 1937.

3

Grant JCB. Grant’s Atlas of Anatom y. Baltim ore, MD: William s & Wilkins Co, 1943.

4

Grant JCB, Cates HA. Grant’s Dissector (A Handbook for Dissectors). Baltim ore, MD: William s & Wilkins Co, 1940.

Reviewers RADIOLOGIC FIGURE CONTRIBUTORS Jo e l A. Vile n sky, Ph D Professor, Departm ent of Anatom y and Cell Biology Indiana University School of Medicine Fort Wayne, Indiana Ed w ard C. We b e r, DO The Im aging Center Fort Wayne, Indiana

FACULTY REVIEWERS Ern e st Ad e g h at e , MD, Ph D, DSc Professor and Chair College of Medicine and Health Sciences United Arab Em irates University Al-Ain, United Arab Em irates

Dian a Rh o d e s, DVM, Ph D Professor of Anatom y and Chair Dep artm ent of Anatom y Paci c Northwest University of Health Sciences Yakim a, Washington Bruce Wain m an , Ph D Associate Professor, Pathology and Molecular Medicine Director, Education Program in Anatom y McMaster University Ontario, Canada

STUDENT REVIEWERS To d d Ch rist e n se n University of Medicine and Health Sciences, St. Kitts Marg are t Co n n o lly Tufts University School of Medicine

Je an -p o l Be aut h ie r, MD, Ph D Professor of Forensic Patholog y Université libre de Bruxelles Brussels, Belgium

Laura De sch am p s Philadelphia College of Osteopathic Medicine

Je n n ife r A. Carr, Ph D Preceptor Harvard University Cam bridge, Massachusetts

Dust un Fie ld Trinity School of Medicine

Do n ald J. Fle t ch e r, Ph D Professor and Vice Chair Departm ent of Anatom y and Cell Biology Brody School of Medicine, East Carolina University Greenville, North Carolina Do ug las J. Go uld , Ph D Professor and Vice Chair Departm ent of Biom edical Sciences William Beaum ont School of Medicine, Oakland University Rochester, Michigan Ro b e rt Hag e , MD, Ph D, DLO, MBA Professor and Co-chair School of Medicine, St. George’s University Grenada, West Indies

Kyle Diam o n d Charles E. Schm idt College of Medicine

Trip p Hin e s Jam es H. Quillen Colleg e of Medicine, East Tennessee State University Kim b e r Jo h n se n University of Medicine and Health Sciences, St. Kitts Nalin Lalw an i University of Medicine and Health Sciences, St. Kitts Am y Le sh n e r St. George’s, University of London Garre n Lo w Keck School of Medicine of USC Milcris N. Cald e ro n Mad uro Ponce Health Sciences University School of Medicine

Jo n at h an Kalm e y, Ph D Assistant Dean of Preclinical Education, Professor of Anatom y Lake Erie College of Osteop athic Medicine Erie, Pennsylvania

Kat h e rin e Mo rg an t i Louisiana State University Health Sciences Center, Shreveport

Ran d y J. Kule sza, Ph D Associate Professor Lake Erie College of Osteop athic Medicine Erie, Pennsylvania

Fab ian Ne lso n Avalon University School of Medicine

Elizab e t h Ne lso n University of Utah School of Medicine

Nin a Ng uye n Université de Sherbrooke

vii

viii

REVIEWERS

Ryan Ng uye n College of Osteopathic Medicine of the Paci c, Western University of Health Sciences Be t h an ie Nim m o n s University of South Carolina School of Medicine Ije o m a Oh ad ug h a Meharry Medical College Aksh ay Pat e l Saint Jam es School of Medicine Gab rie lla Re ye s University of Medicine and Health Sciences, St. Kitts Aid a Re zaie University of Utah School of Medicine Ke lly Rusko University of Medicine and Health Sciences, St. Kitts Jo rd an St av University of Medicine and Health Sciences, St. Kitts

Rich ard St e w ard Touro College of Osteop athic Medicine Jo rd an Talan Tufts University School of Medicine Crist in a Vázq ue z University of Medicine and Health Sciences, St. Kitts Be n jam in Yin g Min g Tan Lom a Linda University Alice Yu Mid western University Billy Zh an g University of Medicine and Health Sciences, St. Kitts Lucy Zh u Baylor College of Medicine

Preface This edition of Grant’s Atlas has, like its predecessors, req uired intense research, m arket input, and creativity. It is not enough to rely on a solid reputation; with each new edition, we have adapted and changed m any aspects of the Atlas while m aintaining the com m itm ent to pedagogical excellence and anatom ical realism that has enriched its long history. Medical and health sciences education, and the role of anatom y instruction and application within it, continually evolve to re ect new teaching ap proaches and educational m odels. The health care system itself is changing, and the skills and knowledge that future health care practitioners m ust m aster are changing along with it. Finally, technologic advances in publishing, particularly in online resources and electronic m edia, have transform ed the way students access content and the m ethods by which educators teach content. All of these developm ents have shap ed the vision and directed the execution of this fourteenth edition of Grant’s Atlas, as evidenced by the following key features. Re co lo rizat io n o f t h e o rig in al carb o n -d ust Gra nt ’s At la s im ag e s fro m h ig h -re so lut io n scan s. The entire collection of carbon-dust illustrations were rem astered and recolored for the fourteenth edition using a vibrant new palette. The stunning detail and contrast of the original Grant’s art was m aintained while adding a new level of lum inosity of organs and especially transparency of tissues, enabling dem onstrations of deep er relationship s not p ossible with m erely recolored grayscale illustrations, thereby enhancing the student learning experience. The student is able to visualize and app reciate clearly the newly revealed relationship s between structures, enabling the form ation of three-dim ensional (3D) constructs for each region of the body. The recolorization, enabled by m odern im age processing, allows reproduction and viewing of the im ages—both in print and electronically—with unp recedented high resolution and delity, continuing their vital role inform ing future generations of m edical and health care providers about the structure and function of the hum an body. A unique feature of Grant’s Atlas is that rather than providing an idealized view of hum an anatom y, the classic illustrations represent actual dissections that the stud ent can directly com p are with specim ens in the lab. Because the original m odels used for these illustrations were real cadavers, the accuracy of these illustrations is unparalleled, offering students the best introduction to anatom y possible. Sch e m at ic illust rat io n s. Updated for the fourteenth edition with a m odern uniform style and consistent color palette, the fullcolor schem atic illustrations and orientation gures supplem ent the dissection gures to clarify anatom ical concepts, show the relationships of structures, and give an overview of the body region being studied. The illustrations conform to Dr. Grant’s adm onition to “keep it sim ple”: Extraneous labels were deleted, and som e labels were

added to identify key structures and m ake the illustrations as useful as p ossible to students. Le g e nds w it h e asy-t o - nd clinical applicat io ns. Adm ittedly, artwork is the focus of any atlas; however, the Grant’s legends have long been considered a unique and valuable feature of the Atlas. The observations and com m ents that accom pany the illustrations assist orientation and draw attention to salient points and signi cant structures that m ight otherwise escape notice. Their purpose is to interpret the illustrations without providing exhaustive description. Readability, clarity, and practicality were em phasized in the editing of this edition. Clinical com m ents, which deliver practical “pearls” that link anatom ical features with their signi cance in health care practice, appear in blue text within the gure legends. New clinical com m ents based on current practices have been added in this edition, providing even m ore relevance for students searching for m edical application of anatom ical concepts. En h an ce d d iag n o st ic im ag in g an d surface an at o m y. Because m edical im aging has taken on increased im portance in the diagnosis and treatm ent of injuries and illnesses, diagnostic im ages are used liberally throughout and at the end of each chap ter. Over 100 clinically signi cant m ag netic resonance im ages (MRIs), com p uted tom og rap hy (CT) scans, ultrasound scans, and corresponding orientation drawings are included, m any of which are new to or up dated for this edition. Labeled surface anatom y photographs which, like the illustrations, feature ethnic diversity continue to be an im p ortant feature in this new edition. Up d at e d an d im p ro ve d t ab le s. Tables help students organize com plex inform ation in an easy-to-use form at ideal for review and study. In addition to m uscles, tables sum m arizing nerves, arteries, and other relevant structures are included. Tab les are m ade m ore m eaningful with illustrations strategically placed on the sam e page, dem onstrating the structures and relationships described in the tables. Lo g ical o rg an izat io n an d layo ut . The org anization and layout of the Atlas have always been determ ined with ease of use as the goal. In this edition, to facilitate dissection, the body regions have been reordered in the sam e sequence as the m ore recent and current editions of Grant’s Dissector. The order of plates within every chapter was scrutinized to ensure that it is logical and p edagogically effective. We hop e that you enjoy using this fourteenth edition of Grant’s Atlas and that it becom es a trusted partner in your educational experience. We believe that this new edition safeguard s the Atlas’s historical strengths while enhancing its usefulness to today’s students. An n e M.R. Ag ur Art h ur F. Dalle y II

ix

Recoloring Grant’s Atlas The principal illustrations for Grant’s Atlas, created in the 1940s and 1950s, use classic techniques of carbon dust or wash in pure grayscale. Although the detail of the grayscale carbon-dust illustrations was outstanding (see below gure on the left), the need for color was soon obvious. Early editions of the Atlas layered solid colors over parts of the grayscale artwork to highlight the presence and relationships of im portant structures such as veins, arteries, and nerves. This didactic approach and technology persisted throughout the rst eight editions. In the early 1990s, the Atlas was revised using a com p lex p redigital technique where the original illustrations were photographed and printed on p hotographic paper. The prints were then colorized by hand with photo dyes, and the resulting colored prints were rephotographed for reproduction in print. Although this process resulted in a signi cant enrichm ent of the illustrations, the technique som etim es led to loss of detail and reduction of contrast. Over the next several editions, the color of the digital im ages were adjusted and enhanced (see below gure in the m iddle). In the late 1990s, the University of Toronto assum ed care of the original illustrations. The illustrations had been handled roughly over their long lives and were in m any cases deteriorating due to their non-archival substrates. In 2008, an interdiscip linary team 1 of com m unications scholars, illustrators, and archivists app lied for and received funding from the Social Sciences and Hum anities Research Council of Canada to study the illustrations and to create a digital archive of the corpus. The team catalogued, docum ented, and scanned the artifacts at high resolution. The effort revealed a num ber of “lost” illustrations am ong the m ore than 1,000 im ag es. Som e of these im ag es have been restored to the current edition. Once the database of high-resolution im ages was com piled, the possibility arose to “rem aster” and recolor the im ages for the next

Original Carbon-Dust

1

edition of Grant’s Atlas. A system was set up to clean the im ages and create new layers of color. • Alm ost all of the original illustrations contained handlettered labels and leader lines that had to be rem oved. This was accom plished by the careful use of digital cloning and retouching tools. • The tonal range and contrast was adjusted to m axim ize clarity and dynam ic range. • A series of color layers were added over the cleaned scans, based on a carefully chosen palette. Most layers were set to the color transfer m ode, which was chosen to assure that the grayscale balance of the underlying scans would not be altered. • All of the recolored illustrations went through num erous rounds of revision with the authors to assure accuracy and re ect the pedagogic needs of the new edition. This work was overseen by Nicholas Woolridge and carried out by two graduates of the Master of Science in Biom edical Com m unications (MScBMC) p rogram : Nicole Clough and Marissa Webber. The retouching p rocess was designed to preserve the d etail, texture, and contrast of the original artwork (see below im age on the right), allowing the illustrations to continue inform ing students about the structure and function of the hum an body for decades to com e.

Thirteenth Edition with Added Color

Nich o las Wo o lrid g e Director, Master of Science in Biom edical Com m unications Program University of Toronto Septem ber 2015

Fourteenth Edition with Enhanced Color and Detail

Led by Kim Sawchuk, from Concordia University, and included Nancy Marrelli, Nicholas Woolridge, Brian Sutherland, Nina Czegledy, Mél Hogan, Dave Mazierski, and Margot Mackay.

x

Acknowledgm ents Starting with the rst edition of Grant’s Atlas p ublished in 1943, m any people have given generously of their talents and expertise and we acknowledge their particip ation with heartfelt gratitude. Most of the original carbon-dust halftones on which this book is based were created by Dorothy Foster Chubb, a pupil of Max Brödel and one of Canada’s rst professionally trained m edical illustrators. She was later joined by Nancy Joy. Mrs. Chubb was m ainly responsible for the artwork of the rst two ed itions and the sixth edition; Professor Joy, for those in between. In subsequent editions, ad ditional line and halftone illustrations by Elizabeth Blackstock, Elia Hopper Ross, and Marguerite Drum m ond were added. In recent editions, the artwork of Valerie Oxorn and the surface anatom y photograp hy of Anne Rayner of Vanderbilt University Medical Center’s Medical Art Group have augm ented the m odern look and feel of the atlas. Much credit is also due to Charles E. Storton for his role in the preparation of the m ajority of the original dissections and prelim inary photographic work. We also wish to acknowledge the work of Dr. Jam es Anderson, a p upil of Dr. Grant, under whose stewardship the seventh and eighth editions were published. The following individuals also provided invaluable contributions to previous editions of the atlas and are gratefully acknowledged: C.A. Arm strong, P.G. Ashm ore, D. Baker, D.A. Barr, J.V. Basm ajian, S. Bensley, D. Bilbey, J. Bottos, W. Boyd, J. Callagan, H.A. Cates, S.A. Crooks, M. Dickie, C. Duckwall, R. Duckwall, J.W.A. Duckworth, F.B. Fallis, J.B. Francis, J.S. Fraser, P. George, R.K. George, M.G. Gray, B.L. Guyatt, C.W. Hill, W.J. Horsey, B.S. Jad en, M.J. Lee, G.F. Lewis, I.B. MacDonald, D.L. MacIntosh, R.G. MacKenzie, S. Mader, K.O. McCuaig, D. Mazierski, W.R. Mitchell, K. Nancekivell, A.J.A. Noronha, S. O’Sullivan, V. Oxorn, W. Pallie, W.M. Paul, D. Rini, C. Sandone, C.H. Sawyer, A.I. Scott, J.S. Sim pkins, J.S. Sim pson, C.G. Sm ith, I.M. Thom pson, J.S. Thom pson, N.A. Watters, R.W. Wilson, B. Vallecoccia, and K. Yu.

FOURTEENTH EDITION We are indebted to our students, colleagues, and form er professors for their encouragem ent—especially Joel Vilensky, Sherry Downie, Ryan Sp littgerber, Mitchell T. Hayes, Edward Weber, and Douglas J. Gould for their invaluable inp ut. We wish to thank Dr. Joel A. Vilensky and Dr. Edward C. Weber for their contribution of new im ages to update and enhance the im aging sections of this edition. We extend our gratitude to Professors Nick Woolridge and David Mazerski who develop ed the carbon-dust recolorization p rocess and along with Nicole Clough and Marissa Webber who recolorized all of the carb on-dust im ages. Their artistic skills and anatom ical insights m ade substantial contributions to this edition. We would also like to acknowledg e Jennifer Clem ents, Art Director at Wolters Kluwer, who m anaged the art program for this edition. Special thanks go to everyone at Wolters Kluwer—especially Crystal Taylor, Senior Acq uisitions Editor, and Greg Nicholl, Senior Product Developm ent Editor. We also thank Bridgett Dougherty, Production Project Manager. All of your efforts and exp ertise are m uch appreciated. We would like to thank the hundreds of instructors and students who have over the years com m unicated via the p ublisher and directly with the editor their suggestions for how this Atlas m ight be im proved. Finally, we would like to acknowledge the reviewers who reviewed previous editions of the Atlas as well as the reviewers who reviewed the fourteenth edition and provided expert advice on the developm ent of this edition.

xi

Contents Dr. John Charles Boileau Grant Reviewers vii Preface ix Recoloring Grant’s Atlas x Acknowledgm ents xi List of Tables xiv Figure and Table Credits xvi

vi

Medial Wrist and Hand 175 Bones and Joints of Wrist and Hand 176 Function of Hand: Grips and Pinches 183 Im ag ing and Sectional Anatom y 184

CHAPTER 3 Th o rax .............................................................191

CHAPTER 1 Back .....................................................................1 Overview of Vertebral Colum n 2 Cervical Spine 8 Craniovertebral Joints 12 Thoracic Spine 14 Lum bar Spine 16 Ligam ents and Intervertebral Discs 18 Bones, Joints, and Ligam ents of Pelvic Girdle Anom alies of Vertebrae 29 Muscles of Back 30 Suboccipital Region 40 Spinal Cord and Meninges 42 Vertebral Venous Plexuses 50 Com ponents of Sp inal Nerves 51 Derm atom es and Myotom es 54 Autonom ic Nerves 56 Im aging of Vertebral Colum n 60

23

CHAPTER 2 Up p e r Lim b .......................................................63 System ic Overview of Upp er Lim b 64 Bones 64 Nerves 72 Arteries 76 Veins and Lym p hatics 78 Musculofascial Com p artm ents 82 Pectoral Region 84 Axilla, Axillary Vessels, and Brachial Plexus 91 Scapular Region and Sup er cial Back 102 Arm and Rotator Cuff 106 Joints of Shoulder Region 120 Elbow Region 128 Elbow Joint 134 Anterior Forearm 140 Anterior Wrist and Palm of Hand 148 Posterior Forearm 164 Posterior Wrist and Dorsum of Hand 167 Lateral Wrist and Hand 172

xii

Pectoral Region 192 Breast 194 Bony Thorax and Joints 202 Thoracic Wall 209 Thoracic Contents 217 Pleural Cavities 220 Mediastinum 221 Lungs and Pleura 222 Bronchi and Bronchopulm onary Segm ents 228 Innervation and Lym phatic Drainage of Lungs 234 External Heart 236 Coronary Vessels 246 Conduction System of Heart 250 Internal Heart and Valves 251 Sup erior Mediastinum and Great Vessels 258 Diap hragm 265 Posterior Thorax 266 Overview of Autonom ic Innervation 276 Overview of Lym phatic Drainage of Thorax 278 Sectional Anatom y and Im aging 280

CHAPTER 4 Ab d o m e n ........................................................287 Overview 288 Anterolateral Abdom inal Wall 290 Inguinal Region 300 Testis 310 Peritoneum and Peritoneal Cavity 312 Digestive System 322 Stom ach 323 Pancreas, Duodenum , and Spleen 326 Intestines 330 Liver and Gallbladder 340 Biliary Ducts 350 Portal Venous System 354 Posterior Abdom inal Viscera 356 Kidneys 359 Posterolateral Abdom inal Wall 363 Diap hragm 368 Abdom inal Aorta and Inferior Vena Cava Autonom ic Innervation 370

369

CONTENTS Lym phatic Drainage 376 Sectional Anatom y and Im aging

380

CHAPTER 5 Pe lvis an d Pe rin e um ......................................387 Pelvic Girdle 388 Ligam ents of Pelvic Girdle 395 Floor and Walls of Pelvis 396 Sacral and Coccygeal Plexuses 400 Peritoneal Re ections in Pelvis 402 Rectum and Anal Canal 404 Organs of Male Pelvis 410 Vessels of Male Pelvis 416 Lym phatic Drainage of Male Pelvis and Perineum 418 Innervation of Male Pelvic Organs 420 Organs of Fem ale Pelvis 422 Vessels of Fem ale Pelvis 432 Lym phatic Drainage of Fem ale Pelvis and Perineum 434 Innervation of Fem ale Pelvic Organs 436 Subperitoneal Region of Pelvis 440 Surface Anatom y of Perineum 442 Overview of Male and Fem ale Perineum 444 Male Perineum 449 Fem ale Perineum 458 Pelvic Angiography 466

CHAPTER 6 Lo w e r Lim b .....................................................467 System ic Overview of Lower Lim b 468 Bones 468 Nerves 472 Blood Vessels 478 Lym phatics 482 Musculofascial Com p artm ents 484 Retro-Inguinal Passage and Fem oral Triangle 486 Anterior and Medial Com p artm ents of Thigh 490 Lateral Thigh 497 Bones and Muscle Attachm ents of Thigh 498 Gluteal Region and Posterior Com partm ent of Thigh 500 Hip Joint 510 Knee Region 516 Knee Joint 522 Anterior and Lateral Compartments of Leg, Dorsum of Foot 536 Posterior Com p artm ent of Leg 546 Tibio bular Joints 556 Sole of Foot 557 Ankle, Subtalar, and Foot Joints 562 Im aging and Sectional Anatom y 576

CHAPTER 7 He ad .................................................................581 Cranium 582 Face and Scalp 602 Meninges and Meningeal Spaces

611

x iii

Cranial Base and Cranial Nerves 616 Blood Supp ly of Brain 622 Orbit and Eyeball 626 Parotid Reg ion 638 Tem p oral Region and Infratem poral Fossa 640 Tem p orom andibular Joint 648 Tongue 652 Palate 658 Teeth 661 Nose, Paranasal Sinuses, and Pterygopalatine Fossa 666 Ear 679 Lym phatic Drainage of Head 692 Autonom ic Innervation of Head 693 Im ag ing of Head 694 Neuroanatom y: Overview and Ventricular System 698 Telencephalon (Cerebrum ) and Diencephalon 701 Brainstem and Cerebellum 710 Im ag ing of Brain 716

CHAPTER 8 Ne ck .................................................................721 Subcutaneous Structures and Cervical Fascia 722 Skeleton of Neck 726 Regions of Neck 728 Lateral Region (Posterior Triangle) of Neck 730 Anterior Region (Anterior Triangle) of Neck 734 Neurovascular Structures of Neck 738 Visceral Com p artm ent of Neck 744 Root and Prevertebral Region of Neck 748 Subm andibular Region and Floor of Mouth 754 Pharynx 758 Isthm us of Fauces 764 Larynx 770 Sectional Anatom y and Im aging of Neck 778

CHAPTER 9 Cran ial Ne rve s ................................................783 Overview of Cranial Nerves 784 Cranial Nerve Nuclei 788 Cranial Nerve I: Olfactory 790 Cranial Nerve II: Optic 791 Cranial Nerves III, IV, and VI: Oculom otor, Trochlear, and Abducent 793 Cranial Nerve V: Trig em inal 796 Cranial Nerve VII: Facial 803 Cranial Nerve VIII: Vestibulocochlear 804 Cranial Nerve IX: Glossop haryngeal 806 Cranial Nerve X: Vagus 808 Cranial Nerve XI: Spinal Accessory 810 Cranial Nerve XII: Hypoglossal 811 Sum m ary of Autonom ic Ganglia of Head 812 Sum m ary of Cranial Nerve Lesions 813 Sectional Im aging of Cranial Nerves 814 INDEX 8 1 7

List of Tables CHAPTER 1 Back 1.1 1.2 1.3 1.4 1.5

Typ ical Cervical Vertebrae (C3–C7) Thoracic Vertebrae Lum bar Vertebrae Sup er cial and Interm ediate Layers of Intrinsic Back Muscles Deep Layers of Intrinsic Back Muscles

CHAPTER 2 Up p e r Lim b 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10 2.11 2.12 2.13 2.14 2.15 2.16

Cutaneous Nerves of Upper Lim b Clinical Manifestations of Nerve Root Com p ression: Upper Lim b Derm atom es of Up per Lim b Anterior Axio-Appendicular Muscles Arteries of Proxim al Up per Lim b (Shoulder Region and Arm ) Brachial Plexus Sup er cial Back (Posterior Axio-App endicular) and Deltoid Muscles Scap ular Movem ents Scap ulohum eral Muscles Arm Muscles Arteries of Forearm Muscles of Anterior Forearm Muscles of Hand Arteries of Hand Muscles of Posterior Surface of Forearm Lesions of Nerves of Up per Lim b

CHAPTER 3 Th o rax 3.1 3.2 3.3

Muscles of Thoracic Wall Muscles of Resp iration Surface Markings of Parietal Pleura and Surface Markings of Lungs Covered with Visceral Pleura

CHAPTER 4 Ab d o m e n 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8

xiv

Princip al Muscles of Anterolateral Abd om inal Wall Boundaries of Ing uinal Canal Characteristics of Inguinal Hernias Term s Used to Describ e Parts of Peritoneum Parts and Relationships of Duodenum Schem a of Term inology for Subdivisions of Liver Princip al Muscles of Posterior Abdom inal Wall Autonom ic Innervation of Abdom inal Viscera (Splanchnic Nerves)

CHAPTER 5 Pe lvis an d Pe rin e um 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9

Differences Between Male and Fem ale Pelves Muscles of Pelvic Walls and Floor Nerves of Sacral and Coccygeal Plexuses Arteries of Male Pelvis Lym phatic Drainage of Male Pelvis and Perineum Effect of Sym pathetic and Parasym pathetic Stim ulation on Urinary Tract, Genital System , and Rectum Arteries of Fem ale Pelvis (Derivatives of Internal Iliac Artery [IIA]) Lym phatic Drainage of Structures of Fem ale Pelvis and Perineum Muscles of Perineum

CHAPTER 6 Lo w e r Lim b 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10 6.11 6.12 6.13 6.14 6.15 6.16 6.17 6.18 6.19 6.20 6.21 6.22

Motor Nerves of Lower Lim b Nerve Lesions Cutaneous Nerves of Lower Lim b Nerve Root (Anterior Ram us) Lesions Muscles of Anterior Thigh Muscles of Medial Thigh Muscles of Gluteal Region Muscles of Posterior Thigh (Ham string ) Nerves of Gluteal Region Arteries of Gluteal Region and Posterior Thigh Bursae Around Knee Muscles of Anterior Com p artm ent of Leg Com m on, Sup er cial, and Deep Fibular (Peroneal) Nerves Arterial Supply to Dorsum of Foot Muscles of Lateral Com partm ent of Leg Muscles of Posterior Com p artm ent of Leg Arterial Supply of Leg and Foot Muscles in Sole of Foot—First Layer Muscles in Sole of Foot—Second Layer Muscles in Sole of Foot—Third Layer Muscles in Sole of Foot—Fourth Layer Joints of Foot

CHAPTER 7 He ad 7.1 7.2 7.3 7.4 7.5 7.6

Foram ina and Other Ap ertures of Neurocranium and Contents Main Muscles of Facial Exp ression Nerves of Face and Scalp Arteries of Super cial Face and Scalp Veins of Face Opening s by Which Cranial Nerves Exit Cranial Cavity

LIST OF TABLES 7.7 7.8 7.9 7.10 7.11 7.12 7.13 7.14 7.15

Arterial Supply to Brain Actions of Muscles of Orbit Starting from Prim ary Position Muscles of Orbit Arteries of Orb it Muscles of Mastication (Acting on Tem p orom andibular Joint) Movem ents of Tem p orom andibular Joint Muscles of Tongue Muscles of Soft Palate Prim ary and Second ary Dentition

CHAPTER 8 Ne ck 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9

Platysm a Cervical Regions and Contents Sternocleidom astoid and Trap ezius Muscles of Anterior Cervical Region Arteries of Neck Prevertebral and Scalene Muscles Lateral Vertebral Muscles Muscles of Pharynx Muscles of Larynx

CHAPTER 9 Cran ial Ne rve s 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 9.9 9.10 9.11 9.12 9.13 9.14 9.15 9.16

Sum m ary of Cranial Nerves Olfactory Nerve (CN I) Optic Nerve (CN II) Oculom otor (CN III), Trochlear (CN IV), and Abducent (CN VI) Nerves Trigem inal Nerve (CN V) Branches of Ophthalm ic Nerve (CN V1 ) Branches of Maxillary Nerve (CN V2 ) Branches of Mandibular Nerve (CN V3 ) Facial Nerve (CN VII), Including Motor Root and Interm ediate Nerve Vestibulocochlear Nerve (CN VIII) Glossopharyngeal Nerve (CN IX) Vagus Nerve (CN X) Spinal Accessory Nerve (CN XI) Hypoglossal Nerve (CN XII) Autonom ic Ganglia of Head Sum m ary of Cranial Nerve Lesions

xv

Figure and Table Credits CHAPTER 1 Back

CHAPTER 3 Th o rax

Fig ure s 1.3D&E, 1.4, an d 1.17B. Modi ed from Moore KL, Dalley AF, Ag ur MR. Clinically Oriented Anatom y, 7th ed. Baltim ore, MD: Lippincott William s & Wilkins, 2014. Fig ure s 1.7A–D, 1.9A,B,D&E, 1.14B, 1.15C, 1.18A–C, 1.19A&B, 1.21A&B, 1.31A–E, 1.32A–D, 1.38C, 1.41A&C, 1.42A&B, 1.45B, 1.46A–E, 1.47, 1.48, an d 1.49A&B. Modi ed from Moore KL, Agur MR, Dalley AF. Essential Clinical Anatomy, 5th ed. Baltim ore, MD: Lippincott William s & Wilkins, 2015. Fig ure 1.8A&B. Courtesy of J. Heslin, University of Toronto, Ontario, Canada. Fig ure s 1.8C&D an d 1.50C. Courtesy of D. Arm strong, University of Toronto, Ontario, Canada. Fig ure s 1.9C an d 1.53A–D. Courtesy of D. Salonen, University of Toronto, Ontario, Canada. Fig ure 1.43A–E. Modi ed from Tank PW, Gest TR. Lippincott William s & Wilkins Atlas of Anatom y. Baltim ore, MD: Lippincott William s & Wilkins, 2009. Fig ure s 1.50A&B, 1.51A&B, an d 1.52A&B. Courtesy of the Visible Hum an Project; National Lib rary of Med icine; Visible Man 1805.

Fig ure s 3.7B, 3.14A&B, 3.15B, 3.19, 3.20, 3.27A–C, 3.28A,C,&D, 3.34A–F, 3.43C, 3.48A–C, 3.49A&D, 3.50A&C, 3.53A–C, 3.60C, 3.65A–C, 3.71A&B, 3.77E, an d 3.78F&H. Modi ed from Moore KL, Agur MR, Dalley AF. Essential Clinical Anatom y, 5th ed. Baltim ore, MD: Lipp incott William s & Wilkins, 2015. Fig ure s 3.14C, 3.15A, 3.28B, 3.51A&C–E, 3.52A&B, 3.54B, 3.55B, 3.56B&C, 3.57C, 3.58B, 3.70, an d 3.72B. Modi ed from Moore KL, Dalley AF, Ag ur MR. Clinically Oriented Anatom y, 7th ed. Baltim ore, MD: Lippincott William s & Wilkins, 2014. Fig ure s 3.43B&E, 3.49C, an d 3.57B. Courtesy of I. Verschuur, Joint Departm ent of Med ical Im aging, UHN/ Mount Sinai Hosp ital, Toronto, Ontario, Canada. Fig ure 3.50B&D. Courtesy of I. Morrow, University of Manitoba, Canada. Fig ure 3.51B. Courtesy of Dr. J. Heslin, Toronto, Ontario, Canada. Fig ure 3.52C. Feigenbaum H, Arm strong WF, Ryan T. Feigenbaum ’s Echocardiography, 5th ed. Philadelphia, PA: Lipp incott William s & Wilkins, 2005:116. Fig ure 3.64B. Courtesy of Dr. E.L. Lansdown, University of Toronto, Ontario, Canada. Fig ure s 3.79A–E, 3.80A&B, an d 3.81A&B. Courtesy of Dr. M.A. Haider, University of Toronto, Ontario, Canada.

CHAPTER 2 Up p e r Lim b Fig ure s 2.3A,B,D,&E, 2.5A&B, 2.7A–D, 2.19, 2.22B, 2.25B, 2.34F, 2.45C, 2.48B, 2.53D, 2.61A&B, 2.62, 2.70B, 2.72D, 2.73, 2.80, 2.81A&B, 2.86C&D, 2.87D, an d Tab le 2.8. Modi ed from Moore KL, Agur MR, Dalley AF. Essential Clinical Anatom y, 5th ed. Baltim ore, MD: Lippincott William s & Wilkins, 2015. Fig ure s 2.4A–C, 2.6, 2.8A–D, 2.9A&B, 2.12A&B, 2.13A–C, 2.23B&C, 2.24A&B, 2.29B, 2.44B, 2.47B&D, an d 2.67B. Modi ed from Moore KL, Dalley AF, Ag ur MR. Clinically Oriented Anatom y, 7th ed. Baltim ore, MD: Lippincott William s & Wilkins, 2014. Fig ure 2.10. Modi ed from Tank PW, Gest TR. Lippincott William s & Wilkins Atlas of Anatom y. Baltim ore, MD: Lippincott William s & Wilkins, 2009. Fig ures 2.18A–D, 2.31A–D, 2.33D, 2.35A–D, 2.63A, 2.64A, 2.65A, 2.72A–C, an d 2.83A&B. Modi ed from Clay JH, Pounds DM. Basic Clinical Massage Therapy. Baltim ore, MD: Lippincott William s & Wilkins, 2002. Fig ure s 2.24C an d 2.90F. Courtesy of D. Arm strong, University of Toronto, Ontario, Canada. Fig ure s 2.48C, 2.55B, 2.96A–C, 2.97B–D, an d 2.98A–C. Courtesy of D. Salonen, University of Toronto, Ontario, Canada. Fig ure s 2.48D an d 2.99B. Courtesy of R. Leekam , University of Toronto and West End Diagnostic Im aging, Ontario, Canada. Fig ure 2.54A&B (MRIs). Courtesy of J. Heslin, University of Toronto, Ontario, Canada. Figure 2.90C&D. Courtesy of E. Becker, University of Toronto, Ontario, Canada.

xvi

CHAPTER 4 Ab d o m e n Fig ure s 4.3, 4.5, 4.7A, 4.10D&E, 4.17A–E, 4.18, 4.20C, 4.22B, 4.24A&B, 4.27B, 4.31A–C, 4.32A, 4.33A&B, 4.35A, 4.44 (in se t s), 4.51B&C, 4.54A, 4.55, 4.66A, 4.72A, 4.76B, 4.79C, 4.80A–D, 4.81, 4.83, 4.85A&B, 4.89A,B,&D–F, an d 4.93A–C (sch e m at ics o n le ft ). Modi ed from Moore KL, Agur MR, Dalley AF. Essential Clinical Anatom y, 5th ed. Baltim ore, MD: Lippincott William s & Wilkins, 2015. Fig ure 4.7B. Lockhart RD, Ham ilton GF, Fyfe FW. Anatom y of the Hum an Body. Philadelphia, PA: JB Lippincott, 1959. Fig ure 4.9A–E. Modi ed from Clay JH, Pounds DM. Basic Clinical Massage Therapy, 2nd ed. Baltim ore, MD: Lippincott William s & Wilkins, 2008. Fig ure s 4.10A&B, 4.42C–E, 4.43B, 4.58B&C, 4.62A–H, 4.73A–E, an d 4.85C. Modi ed from Moore KL, Dalley AF, Agur MR. Clinically Oriented Anatom y, 7th ed. Baltim ore, MD: Lippincott William s & Wilkins, 2014. Fig ure s 4.32C (p h o t o ) an d 4.34A. Dudek RW, Louis TM. High-Yield Gross Anatom y, 4th ed. Baltim ore, MD: Lippincott William s & Wilkins, 2010. Fig ure s 4.34B, 4.36, 4.45B, an d 4.61A&B. Courtesy of Dr. J. Heslin, Toronto, Ontario, Canada. Fig ure s 4.34C&D, 4.42B, 4.45A, an d 4.72B. Courtesy of Dr. E.L. Lansdown, University of Toronto, Ontario, Canada. Fig ure 4.42A. Courtesy of Dr. C.S. Ho, University of Toronto, Ontario, Canada. Fig ure 4.47. Courtesy of Dr. K. Sniderm an, University of Toronto, Ontario, Canada.

FIGURE AND TABLE CREDITS Fig ure 4.53B. Courtesy of A.M. Arenson, University of Toronto, Ontario, Canada. Fig ure 4.66B (MRI). Courtesy of G.B. Haber, University of Toronto, Ontario, Canada. Fig ure 4.66B (p h o t o ). Courtesy of Mission Hospital Regional Center, Mission Viejo, California. Fig ure 4.73B (MRI). Courtesy of M. Asch, University of Toronto, Ontario, Canada. Fig ure s 4.91B&D, 4.92B&C, an d 4.93A–C (MRIs). Courtesy of Dr. M.A. Haid er, University of Toronto, Ontario, Canada.

CHAPTER 5 Pe lvis an d Pe rin e um Fig ure s 5.3C, 5.4B&C, 5.11B, 5.12B, 5.16B–D, 5.18A–D, 5.19, 5.26B, 5.27A&B, 5.28B–D, 5.29A&B, 5.38A&B, 5.39B–D, 5.47B–E, 5.48A–F, 5.51B, 5.52B, an d 5.54C. Modi ed from Moore KL, Agur MR, Dalley AF. Essential Clinical Anatomy, 5th ed. Baltim ore, MD: Lippincott William s & Wilkins, 2015. Fig ure 5.7A&B. Snell R. Clinical Anatom y by Regions, 9th ed. Baltim ore, MD: Lip pincott William s & Wilkins, 2012. Fig ure s 5.24A&B (MRIs), 5.30B, 5.43A, 5.57B&E–H, an d 5.64A–D,F,&H. Courtesy of Dr. M.A. Haider, University of Toronto, Ontario, Canada. Fig ure 5.24C. Modi ed from Bickley LS. Bates’ Guide to Physical Exam ination and History Taking, 10th ed. Philadelp hia, PA: Wolters Kluwer Health, 2009. Fig ure s 5.28A, 5.30E&F, 5.33A–C, 5.39A, 5.40, 5.41, an d 5.59B. Modi ed from Moore KL, Dalley AF, Agur MR. Clinically Oriented Anatom y, 7th ed. Baltim ore, MD: Lippincott William s & Wilkins, 2014. Fig ure s 5.30C an d 5.34A&B. Courtesy of A.M. Arenson, University of Toronto, Ontario, Canada. Fig ure 5.35D. Reprinted with perm ission from Stuart GCE, Reid DF. Diagnostic stud ies. In: Copeland LJ. Textbook of Gynecology. Philadelphia, PA: WB Saunders, 1993. Fig ure s 5.43B an d 5.57C. From the Visible Hum an Project; National Library of Medicine; Visible Wom an Im age Num bers 1870 and 1895.

CHAPTER 6 Lo w e r Lim b Fig ure s 6.2A&B, 6.9A&B, 6.12A, 6.13A, 6.15A&B, 6.17B, 6.19C, 6.29A&B, 6.30A, 6.32B&C, 6.38A, 6.45 (sch e m at ics), 6.48B&C, 6.53A, 6.58A&B, 6.61A&B, 6.63D, 6.65A&B, 6.66D, 6.67B, an d 6.72A–C. Modi ed from Moore KL, Ag ur MR, Dalley AF. Essential Clinical Anatom y, 5th ed. Baltim ore, MD: Lippincott William s & Wilkins, 2015. Fig ure 6.3A&C. Courtesy of P. Babyn, University of Toronto, Ontario, Canada. Fig ure s 6.7A–D, 6.12B, 6.13B, 6.24B&C, 6.33B, 6.59A&E, 6.67E, 6.68B, 6.71A&B, 6.74A, 6.75A, 6.76A, 6.77A, 6.80B&C, 6.81D, an d 6.87A. Modi ed from Moore KL, Dalley AF, Agur MR. Clinically Oriented Anatom y, 7th ed. Baltim ore, MD: Lippincott William s & Wilkins, 2014. Fig ure 6.8A&B. Based on Foerster O. The derm atom es in m an. Brain . 1933;56(1):1–39. Fig ure 6.8C&D. Based on Keegan JJ, Garrett FD. The segm ental distribution of the cutaneous nerves in the lim bs of m an. Anat Rec. 1948;102:409–437. Fig ure 6.14B. Courtesy of Dr. E.L. Lansdown, University of Toronto, Ontario, Canada. Fig ure s 6.22A–E&H, 6.29C–F, 6.30B–D, an d 6.62C&D. Modi ed from Clay JH, Pounds DM. Basic Clinical Massage Therapy. Baltim ore, MD: Lippincott William s & Wilkins, 2002.

x vii

Fig ure 6.34A&B. Modi ed from Tank PW, Gest TR. Lippincott William s & Wilkins Atlas of Anatom y. Baltim ore, MD: Lip pincott William s & Wilkins, 2009. Fig ure 6.39A. Courtesy of E. Becker, University of Toronto, Ontario, Canada. Fig ure s 6.39C, 6.56C&D, 6.92C–E (MRIs), an d 6.94A–D (MRIs). Courtesy of Dr. D. Salonen, University of Toronto, Ontario, Canada. Fig ure 6.49C. Courtesy of Dr. Robert Peroutka, Cockeysville, MD. Fig ure 6.70A. Courtesy of Dr. D. K. Sniderm an, University of Toronto, Ontario, Canada. Fig ure 6.82B. Courtesy of E. Becker, University of Toronto, Ontario, Canada. Fig ure s 6.85B an d 6.86B. Courtesy of Dr. W. Kucharczyk, University of Toronto, Ontario, Canada. Fig ure 6.90E. Courtesy of Dr. P. Bobechko, University of Toronto, Ontario, Canada.

CHAPTER 7 He ad Fig ure s 7.1B,E,&F, 7.76B, 7.103A–F, 7.107A–E (MRIs), 7.108A–F, an d 7.109A–C. Courtesy of Dr. D. Arm strong, University of Toronto, Ontario, Canada. Fig ure s 7.3C, 7.6B, 7.17A&B, 7.19, 7.21B&C, 7.29, 7.31B, 7.44A, 7.45B, 7.60B, 7.63C, 7.64A&C, 7.68B, 7.70A&B, 7.71A&B, 7.72A (t o p ), 7.82A&B, 7.84D, 7.98A&C, an d Tab le 7.15. Modi ed from Moore KL, Dalley AF, Ag ur MR. Clinically Oriented Anatom y, 7th ed. Baltim ore, MD: Lippincott William s & Wilkins, 2014. Fig ure s 7.14A, 7.15A&B, 7.18A&B, 7.20B, 7.21A, 7.22A–D, 7.24B, 7.25A&B, 7.30B&C, 7.33B&C, 7.39B,C,&E, 7.42B–E, 7.43A&B, 7.44B, 7.45D, 7.46B, 7.48A&D, 7.51, 7.52A&B, 7.55B&C, 7.56A–C, 7.57A–D, 7.58A&B, 7.59A–C, 7.67A–C, 7.78A–C, 7.79D&E, 7.85A, 7.86A, 7.89B, 7.90C–E, 7.91A&B, an d 7.92A–D. Modi ed from Moore KL, Agur MR, Dalley AF. Essential Clinical Anatom y, 5th ed. Baltim ore, MD: Lipp incott William s & Wilkins, 2015. Fig ure 7.34A–C. Courtesy of I. Verschuur, Joint Departm ent of Medical Im aging, UHN/ Mount Sinai Hospital, Toronto, Ontario, Canada. Fig ure s 7.35A&B, 7.38D, 7.94B&C, an d 7.95B. Courtesy of Dr. W. Kucharczyk, University of Toronto, Ontario, Canada. Fig ure 7.46A. Courtesy of J.R. Buncic, University of Toronto, Ontario, Canada. Fig ure 7.53A–C. Modi ed from Clay JH, Pounds DM. Basic Clinical Massage Therapy. Baltim ore, MD: Lip pincott William s & Wilkins, 2002. Fig ure 7.56 (MRIs). Langland OE, Langlais RP, Preece JW. Principles of Dental Im aging , 2nd ed. Baltim ore, MD: Lip pincott William s & Wilkins, 2002. Fig ure 7.65D. Courtesy of M.J. Phatoah, University of Toronto, Ontario, Canada. Fig ure 7.66E. Courtesy of Dr. B. Libgott, Division of Anatom y/ Departm ent of Surgery, University of Toronto, Ontario, Canada. Fig ure s 7.76C an d 7.77B. Courtesy of E. Becker, University of Toronto, Ontario, Canada. Fig ure 7.96A&B. Courtesy of the Visible Hum an Project; National Library of Medicine; Visible Man 1107 and 1168. Fig ure s 7.99–7.102, 7.104, 7.105B&C, an d 7.106. Colorized from photog raphs provided courtesy of Dr. C.G. Sm ith, which ap pears in Sm ith CG. Serial Dissections of the Hum an Brain . Baltim ore, MD: Urban & Schwarzenber, Inc and Toronto: Gage Publishing Ltd, 1981. (© Carlton G. Sm ith)

xviii

FIGURE AND TABLE CREDITS

CHAPTER 8 Ne ck Fig ure s 8.2A–C, 8.3A, 8.5A&C–G, 8.6B&C, 8.8B, 8.12B, 8.15A–C, 8.17B, 8.19A, 8.36B–F&H–J, 8.37D, an d 8.39. Modi ed from Moore KL, Ag ur MR, Dalley AF. Essential Clinical Anatom y, 5th ed. Baltim ore, MD: Lippincott William s & Wilkins, 2015. Fig ure s 8.4A&B, 8.8D&E, 8.23A, 8.28C, an d 8.31C. Modi ed from Moore KL, Dalley AF, Agur MR. Clinically Oriented Anatom y, 7th ed. Baltim ore, MD: Lip pincott William s & Wilkins, 2014. Fig ure 8.5B. Courtesy of J. Heslin, University of Toronto, Ontario, Canada. Fig ure s 8.7B&C, 8.12A, an d 8.24A&B. Modi ed from Clay JH, Pounds DM. Basic Clinical Massage Therapy. Baltim ore, MD: Lippincott William s & Wilkins, 2002. Fig ure 8.15D. Courtesy of Dr. D. Arm strong, University of Toronto, Ontario, Canada. Fig ure s 8.28A an d 8.43B. Modi ed from Tank PW, Gest TR. Lippincott Williams & Wilkins Atlas of Anatom y. Baltim ore, MD: Lippincott William s & Wilkins, 2009. Fig ure 8.30B. From Liebgott B. The Anatom ical Basis of Dentistry. Philadelphia, PA: Mosby, 1982.

Fig ure 8.37A. Rohen JW, Yokochi C, Lutjen-Drecoll E, et al. Color Atlas of Anatom y, 5th ed. Baltim ore, MD: Lippincott William s & Wilkins, 2002. Fig ure s 8.37C an d 8.40A–C. Courtesy of Dr. D. Salonen, University of Toronto, Ontario, Canada. Fig ure 8.42A. Courtesy of Dr. E. Becker, University of Toronto, Ontario, Canada. Fig ure 8.43A. Siem ens Medical Solutions USA, Inc.

CHAPTER 9 Cran ial Ne rve s Fig ure s 9.3, 9.5A&B, 9.6A–C, 9.7, 9.8C&D, 9.10A, 9.11B, 9.13B–E, 9.14A, 9.15B&C, 9.16D, 9.17A, 9.18A,B,&D, 9.19A, 9.20B, an d 9.21. Modi ed from Moore KL, Ag ur MR, Dalley AF. Essential Clinical Anatom y, 5th ed. Baltim ore, MD: Lippincott William s & Wilkins, 2015. Fig ure 9.16C. Modi ed from Moore KL, Dalley AF, Agur MR. Clinically Oriented Anatom y, 7th ed. Baltim ore, MD: Lipp incott William s & Wilkins, 2014. Fig ure s 9.23A–F an d 9.24A–C. Courtesy of Dr. W. Kucharczyk, University of Toronto, Ontario, Canada.

https://t.me/MedicalBooksStore

CHAPTER 1

Back Overview of Vertebral Colum n ...............................................2 Cervical Spine ........................................................................8 Craniovertebral Joints ..........................................................12 Thoracic Spine .....................................................................14 Lum bar Spine ......................................................................16 Ligam ents and Intervertebral Discs ......................................18 Bones, Joints, and Ligam ents of Pelvic Girdle .......................23 Anom alies of Vertebrae ........................................................29 Muscles of Back ...................................................................30 Suboccipital Region .............................................................40 Spinal Cord and Meninges...................................................42 Vertebral Venous Plexuses ....................................................50 Com ponents of Spinal Nerves..............................................51 Derm atom es and Myotom es ...............................................54 Autonom ic Nerves ...............................................................56 Im aging of Vertebral Colum n ...............................................60

Back

2

OVERVIEW OF VERTEBRAL COLUMN

Neural arch Foramen transversarium Elements of transverse process

7 cervical vertebrae

Transverse (posterior tubercle) Costal (anterior tubercle) Neurocentral junction Centrum

Tubercle of rib

Rib

Intervertebral foramina

Cervical vertebra

Transverse process

Head of rib Intervertebral discs

12 thoracic vertebrae

Neurocentral junction Centrum Thoracic vertebra

Transverse Elements Costal 5 lumbar vertebrae Centrum Lumbar vertebra Sacrum Hip bone

Coccyx

Elements

Transverse Costal

Centrum Sacral vertebra

A. Lateral View

1.1

B. Superior Views

OVERVIEW OF VERTEBRAL COLUMN

A. Verteb ral colum n showing articulation with skull and hip bone. • The verteb ral colum n usually consists of 24 sep arate (p resacral) verteb rae, 5 fused verteb rae in the sacrum , and variab ly 4 fused or sep arated coccyg eal verteb rae. Of th e 24 sep arate verteb rae, 12 sup p ort the rib s (thoracic verteb rae), 7 are in the neck (cervical verteb rae, and 5 are in the lum b ar reg ion (lum b ar verteb rae).

• The spinal nerves exit the vertebral (spinal) canal via the intervertebral (IV) foram ina. There are 8 cervical, 12 thoracic, 5 lum bar, 5 sacral, and 1 to 2 coccygeal spinal nerves. B. Hom ologous parts of vertebrae. A rib is a free costal elem ent in the thoracic region; in the cervical and lum bar regions, it is represented by the anterior part of a transverse process, and in the sacrum , b y the anterior p art of the lateral m ass.

Back

OVERVIEW OF VERTEBRAL COLUMN

Primary* and secondary** curvatures:

Vertebral regions/levels:

Primary curvature:

3

Vertebral regions/levels: C1

C1

Cervical lordosis**

C7 T1

C7 T1

T12 L1

Thoracic kyphosis* L5 Sacrum Coccyx T12 L1

A. Lateral View

Lumbar lordosis** Halves of neural arch Vertebral arch Vertebral foramen

Neurocentral joint

Centrum

Site of hyaline cartilage

L5

Centrum

B. Superior View

CURVATURES OF VERTEBRAL COLUMN A. Fetus. Note the C-shaped curvature of the fetal spine, which is concave anteriorly over its entire length. B. Developm ent of the vertebrae. At b irth, a vertebra consists of three bony parts (two halves of the neural arch and the centrum ) united by hyaline cartilage. At age 2, the halves of each neural arch begin to fuse, proceeding from the lum bar to the cervical region; at approxim ately age 7, the arches begin to fuse to the centrum , p roceeding from the cervical to lum bar regions. C. Adult. The four curvatures of the adult vertebral colum n includ e the cervical lordosis, which is convex anteriorly and lies between vertebrae C1 and T2; the thoracic

Sacrum

Sacrococcygeal kyphosis*

Coccyx

Body

C. Lateral View

1.2 kyp hosis, which is concave anteriorly, between vertebrae T2 and T12; the lum bar lordosis, convex anteriorly and lying between T12 and the lum bosacral joint; and the sacrococcygeal kyphosis, concave anteriorly and sp anning from the lum bosacral joint to the tip of the coccyx. The anteriorly concave thoracic kyphosis and sacrococcygeal kyp hosis are prim ary curves, and the anteriorly convex cervical lordosis and lum bar lordosis are secondary curves that develop after birth. The cervical lordosis develops when the child begins to hold the head up, and the lum bar kyphosis develops when the child begins to walk.

Back

4

OVERVIEW OF VERTEBRAL COLUMN 1

1 1 2 3 4 5 6 7 1

2

Spinous process (SP)

3 4 5

Cervical vertebrae VB

7 Articular facet (FT)

1 3 4 Thoracic vertebrae

6 Vertebral body (VB)

8

5 6 7 1 2

TVP

3 TVP Thoracic vertebrae

SP

4 5

FT

8

6

9

7 VB

10

8 9

11

10

10 12

11 12

Pedicle (P)

4

TVP VB

7

9 Transverse process (TVP)

SP

6

7 FT

3

Cervical vertebrae

5

5 FT

TVP

2 3 4

2

SP

2

11

1 1

12 TVP

2

1 VB

2

SP

VB

3

3 Lumbar vertebrae

SP

4

2 Lumbar vertebrae

TVP

3

5

4

4

5 5 Sacrum

Sacrum

Coccyx

A. Lateral View

Coccyx (1 – 4)

B. Posterior View

C. Anterior View

Inferior articular process

TVP

1.3

PARTS OF VERTEBRAL COLUMN

A. Lateral view. B. Posterior view. C. Anterior view. D. and E. Parts of a typical vertebra (e.g., the 2nd lum bar vertebra). FT, facet for articulation with the ribs; L, lam ina; P, p ed icle; SP, spinous process; TVP, transverse p rocess; VB, vertebral body.

1 2 3 4 5

Superior articular facet

Spinous process

L P

Vertebral foramen

Vertebral body

D. Superior View

Superior vertebral notch

Lamina (L)

Superior articular process TVP

TVP

P

P

Vertebral body

SP Inferior vertebral notch Inferior E. Lateral View articular process

Inferior articular facet

OVERVIEW OF VERTEBRAL COLUMN

Back

5

Uncus of body (uncinate process) Superior articular facet

Zygapophysial (facet) joint Cervical vertebrae

Foramen transversarium

Inferior articular facet Uncus of body (uncinate process) Superior articular facet

Zygapophysial (facet) joint

Superior articular facet Facet for tubercle of rib

Facets for head of rib

Thoracic vertebrae

Key Flexion Extension Lateral flexion to right

Inferior articular facet

Zygapophysial (facet) joint

Lateral flexion to left Rotation to left Rotation to right Superior articular facet Transverse process Lumbar vertebrae

Inferior articular facet Superior Views - arrows indicate direction of movement of superior adjacent vertebra (not shown) relative to the inferior vertebra (shown here)

VERTEBRAL FEATURES AND MOVEMENTS • In the thoracic and lum bar regions, the articular processes/ facets lie p osterior to the vertebral bodies and in the cervical region posterolateral to the bodies. Superior articular facets in the cervical region face m ainly superiorly, in the thoracic region, m ainly p osteriorly, and in the lum bar region, m ainly m edially. The change in direction is gradual from cervical to thoracic but abrupt from thoracic to lum bar. • Althoug h m ovem ents between adjacent vertebrae are relatively sm all, the sum m ation of all the sm all m ovem ents p roduces a considerab le range of m ovem ent of the vertebral colum n as a whole.

Lateral Views - arrows indicate direction of movement of the superior and inferior vertebra relative to each other

1.4 • Movem ents of the vertebral colum n are freer (have greater rang e of m otion) in the cervical and lum bar regions than in the thoracic region. Lateral bending is freest in the cervical and lum bar regions; exion is greatest in the cervical region; extension is m ost m arked in the lum bar region, but the interlocking articular processes prevent rotation. • The thoracic region is m ost stable because of the external support gained from the articulations of the ribs and costal cartilages with the sternum . The direction of the articular facets perm its rotation, but exion, extension, and lateral bending are severely restricted.

Back

6

OVERVIEW OF VERTEBRAL COLUMN C1

C1

C2 C3 C4 C5 C6 C7

A. Lateral View

B. Lateral Radiograph

C 5

C 4

C 3

C 2

C1

C6

C7

C. Lateral View

D. Lateral Radiograph C2 C3 C4 C5 C6 C7

E. Anterior View

1.5

F. Oblique Radiograph

SURFACE ANATOMY WITH RADIOGRAPHIC CORRELATION OF SELECTED MOVEMENTS OF THE CERVICAL SPINE

A. Extension of the neck. B. Radiograph of the extended cervical spine. C. Flexion of the neck. D. Rad iograph of the exed cervical

sp ine. E. Head rotated (turned) to left. F. Radiograph of cervical sp ine rotated to left.

Back

OVERVIEW OF VERTEBRAL COLUMN

7

L1 L1 L2

Extension (A)

L2

L3 Flexion (C)

L3

L4

L4

L5

S1

L5

B. Lateral View

S1

A. Lateral Radiograph, Lumbar Vertebrae Extended

C. Lateral Radiograph, Lumbar Vertebrae Flexed

xion (E)

l fle era

th 11

t La

th 12

L1

La

rib

ension

l ext a r te

b ri

L2 L3

L4

L5 S1

D. Anterior View E. Anteroposterior

Radiograph, Lumbar Vertebrae Laterally Flexed to Right

SURFACE ANATOMY WITH RADIOGRAPHIC CORRELATION OF SELECTED MOVEMENTS OF THE LUMBAR SPINE A. Radiograph of the extended lum bar spine. B. Schem atic illustration of exion and extension of the trunk. C. Radiograp h of the exed lum bar spine. D. Schem atic illustration of lateral (side) exion of the trunk. E. Radiograph of the lum bar spine during lateral bending.

1.6

The range of movement of the vertebral column is lim ited by the thickness, elasticity, and compressibility of the IV discs; shape and orientation of the zygapophysial joints; tension of the joint capsules of the zygapophysial joints; resistance of the ligaments and back muscles; connection to thoracic (rib) cage and bulk of surrounding tissue.

Back

8

CERVICAL SPINE Posterior tubercle Posterior arch Superior articular facet Foramen transversarium Transverse process Anterior arch Anterior tubercle

Atlas (C1)

Inferior articular process Transverse process Superior articular facet

1.7

CERVICAL SPINE

A. Disarticulated cervical vertebrae. The bodies of the cervical vertebrae can be dislocated in neck injuries with less force than is required to fracture them . Because of the large vertebral canal in the cervical region, som e dislocation can occur without dam aging the spinal cord. When a cervical vertebra is severely dislocated, it injures the spinal cord. If the dislocation d oes not result in “facet jum ping” with locking of the displaced articular processes, the cervical vertebrae m ay self-reduce (“slip back into place”) so that a radiograph m ay not indicate that the cord has been injured. Magnetic resonance im aging (MRI) m ay reveal the resulting soft tissue dam age. Aging of the IV disc com bined with the changing shape of the vertebrae results in an increase in com p ressive forces at the periphery of the vertebral bodies, where the disc attaches. In response, osteophytes (bony spurs) com m only develop around the m arg ins of the verteb ral body, especially along the outer attachm ent of the IV disc. Sim ilarly, as altered m echanics place greater stresses on the zygapophysial joints, osteophytes develop along the attachm ents of the joint capsules, especially those of the superior articular p rocess.

Axis (C2)

Dens (odontoid process)

Transverse process: Posterior tubercle Groove for spinal nerve Anterior tubercle

C3

Foramen transversarium

C4

Spinous process

Uncus of body (uncinate process)

TABLE 1.1

a

Body

TYPICAL CERVICAL VERTEBRAE ( C3 –C7 ) a

Pa rt

Distinctive Cha ra cteristics

Body

Small and wider from side to side than anteroposteriorly; superior surface is concave with an uncus of body (uncinate process bilaterally); inferior surface is convex

Vertebral foramen

Large and triangular

Transverse processes

Foramina transversaria small or absent in vertebra C7; vertebral arteries and accompanying venous and sympathetic plexuses pass through foramina, except C7 foramina, which transmits only small accessory vertebral veins; anterior and posterior tubercles separated by groove for spinal nerve

Articular processes

Superior articular facets directed superoposteriorly; inferior articular facets directed infero-anteriorly; obliquely placed facets are most nearly horizontal in this region

Spinous process

Short (C3–C5) and bi d, only in Caucasians (C3–C5); process of C6 is long but that of C7 is longer; C7 is called “vertebra prominens”

C1 and C2 vertebrae are atypical.

Articular process

C5

Inferior Superior C6

C7

A. Superior Views

CERVICAL SPINE

Atlas (C1): Anterior arch Anterior tubercle

Back

9

C1

C2 Dens Axis (C2) Body

Uncovertebral joint

Uncovertebral joint Transverse process:

External occipital protuberance

C3

Anterior tubercle Posterior tubercle Groove for spinal nerve

C4

Uncus of body (uncinate process)

C5

Posterior atlanto-occipital membrane

C1

Posterior arch of atlas

C6

C7 Nuchal ligament

B. Anterior View

Posterior arch

Anterior tubercle of atlas (C1)

Posterior tubercle

Axis (C2)

Interspinous ligament Ligamentum flavum Spinous process of C7 vertebra Supraspinous ligament

Column of articular processes

Anterior tubercle Groove for spinal nerve

C7 Anterior longitudinal ligament

D. Lateral View

Posterior tubercle

Lamina

Spinous processes C7

Zygapophysial joint

C. Lateral View

CERVICAL SPINE (continued ) B. and C. Articulated cervical vertebrae. D. Ligam ents.

1.7

Back

10

CERVICAL SPINE

D FJ

AT

C3 Uncinate process of body of C5

C1

C2

FJ

Uncovertebral joint Pedicle

TVP

C3 UV

C7

C4

1st rib Transverse process of T2 Clavicle Spinous process of T2

C. Anterior View Key A AA AT C1–C7 D FJ La P

A. Anteroposterior View

AA

Anterior tubercle of transverse process Anterior arch of C1 Anterior tubercle of C1 Vertebrae Dens (odontoid) process of C2 Zygapophysial (facet) joint Lamina Posterior tubercle of transverse process

PA PT SF SP T TVP UV VC

Posterior arch of C1 Posterior tubercle of C1 Superior articular facet of C1 Spinous process Foramen transversarium Transverse process Uncovertebral joint Vertebral canal

D

Posterior arch of atlas (C1)

AT AA C2

Transverse process

C3

Inferior articular process

AA

D

C1 SF

VC PA

C4

Superior articular process Zygapophysial (facet) joint

PT C2

C5

Spinous process of C7

PA

La

C3

La C4

C6

FJ SP

C7

B. Lateral View

1.8

D. Posterior View

IMAGING OF THE CERVICAL SPINE

A. and B. Radiographs. The arrowheads dem arcate the m argins of the (black) colum n of air in the trachea. C. and D. Three-dim ensional reconstructed com puted tom ographic (CT) im ages.

Back

CERVICAL SPINE

Posterior tubercle

11

Posterior arch

Groove for vertebral artery Foramen transversarium

Vertebral foramen (for spinal cord)

Spinous process (bifid)

Transverse ligament of atlas

Transverse process

Foramen for dens Anterior arch

Facet for dens Anterior tubercle

Vertebral foramen

Inferior articular process

Lateral mass

Superior articular facet

Lamina

Transverse process Superior articular facet

A. Atlas

Body

B. Axis

Dens

Facet for atlas

Superior Views Atlantooccipital joints D A

A

A

A D

Median atlanto-axial joint

C2

C2 Lateral atlanto-axial joints

D. Anterior View Key A: Lateral mass of atlas; D: Dens of axis; C2: Axis

C. Anteroposterior View Tectorial membrane Superior longitudinal band of cruciate ligament

Apical ligament of dens Anterior atlanto-occipital membrane Anterior cavity of median atlanto-axial joint Dens of axis Body of axis (C2) Anterior longitudinal ligament

Transverse ligament of atlas/band of cruciate ligament Vertebral artery Posterior atlanto-occipital membrane Inferior longitudinal band of cruciate ligament Posterior atlanto-axial membrane Ligamentum flavum Interspinous ligament

E. Median Section

ATLAS AND AXIS AND THE ATLANTO-AXIAL JOINT

Posterior longitudinal ligament (cut edge and posterior surface)

1.9

A. Atlas. B. Axis. C. Radiograp h taken through the op en m outh. D. Articulated atlas and axis. E. Median section with ligam ents. The structures highlighted in the sam e color are continuous.

12

Back

CRANIOVERTEBRAL JOINTS

Occipital bone

Anterior atlanto-occipital membrane

Joint capsule of atlanto-occipital joint Atlas Joint capsule of lateral atlanto-axial joint

Anterior atlanto-axial membrane

Axis

A. Anterior View

Anterior longitudinal ligament

Occipital bone Posterior atlanto-occipital membrane Foramen for vertebral artery

Groove for vertebral artery

Joint capsule of lateral atlanto-axial joint

Posterior atlanto-axial membrane

Posterior tubercle of atlas Spinous process of axis (bifid)

B. Posterior View

Basilar artery

1.10

Foramen magnum (dashed line)

CRANIOVERTEBRAL JOINTS AND VERTEBRAL ARTERY

A. Anterior atlanto-axial and atlanto-occipital m em branes. The anterior longitudinal ligam ent ascends to blend with, and form a central thickening in, the anterior atlanto-axial and atlantooccipital m em branes. B. Posterior atlanto-axial and atlantooccipital m em branes. Inferior to the axis (C2 vertebra), ligam enta ava occur in this position. C. Tectorial m em brane and vertebral artery. The tectorial m em brane is a superior continuation of the posterior longitudinal ligam ent superior to the body of the axis. After coursing through the foram ina transversaria of vertebrae C6–C1, the vertebral arteries turn m edially, grooving the superior aspect of the posterior arch of the atlas and piercing the posterior atlanto-occipital m em brane (B) . The right and left vertebral arteries traverse the foram en m agnum and m erge intracranially, form ing the basilar artery.

Atlas

Vertebral artery traversing foramina transversaria

C. Posterior View

Tectorial membrane Posterior arch of atlas Axis

CRANIOVERTEBRAL JOINTS

Back

13

Oculomotor nerve (CN III) Dorsum sellae

Trochlear nerve (CN IV) Abducent nerve (CN VI)

Trigeminal nerve (CN V)

Facial nerve (CN VII) Intermediate nerve (CN VII) Vestibulocochlear nerve (CN VIII) Glossopharyngeal nerve (CN IX) Vagus nerve (CN X) Spinal accessory nerve (CN XI)

Tectorial membrane

Cruciform ligament

Hypoglossal nerve (CN XII) Alar ligament

Superior band Transverse ligament of atlas (transverse band)

Spinal nerve C1 Vertebral artery Accessory atlanto-axial ligament

Inferior band

Post ramus of spinal nerve C1 Tectorial membrane (reflected)

Posterior arch of atlas (cut)

A. Posterior View Tectorial membrane (cut edge) Groove for sigmoid sinus

Alar ligament

Cruciform ligament: superior, transverse, and inferior bands

Atlas

Foramen transversarium Axis

B. Posterior View

Tectorial membrane (cut edge)

(Coronal Section)

LIGAMENTS OF ATLANTO-OCCIPITAL AND ATLANTO-AXIAL JOINTS

Anterior tubercle of atlas Dens of axis

Articular cavity Transverse ligament of atlas Superior articular facet of atlas

Foramen transversarium

Groove for vertebral artery Vertebral canal Posterior tubercle of atlas

C. Superior View

Spinous process of axis

1.11

A. Cranial nerves and dura mater of posterior cranial fossa with dura m ater and tentorial membrane incised and removed to reveal the medial atlanto-axial joint. The alar ligam ents serve as check ligam ents for the rotary m ovem ents of the atlanto-axial joints. B. and C. Transverse ligam ent of the atlas. The transverse band of the cruciform ligament, forms the posterior wall of a socket that receives the dens of the axis, forming a pivot joint. Fract ure o f at las. The atlas is a bony ring, with two wedgeshaped lateral m asses, connected by relatively thin anterior and posterior arches and the transverse ligam ent of the atlas (see Figs. 1.12A and C). Vertical forces (e.g., striking the head on bottom of pool) m ay force the lateral m asses apart fracturing one or both of the anterior or posterior arches. If the force is suf cient, rupture of the transverse ligam ent of the atlas will also occur.

Back

14

THORACIC SPINE

C2

Superior articular process

T1

Spinal cord

Superior articular facet

T2

C7

Superior four thoracic vertebrae

T3

T1 Inferior articular process

CSF in subarachnoid space Manubrium

T4

Inferior articular facet T6

T5 Transverse process

Intervertebral disc

T6 Middle four thoracic vertebrae

Transverse costal facet

T7 Spinous process T12

A. Midsagittal MRI

1.12

THORACIC VERTEBRAE

A. MRI of thoracic sp ine. B. Features. Fract ure of th oracic verteb rae. Although the characteristics of the superior aspect of vertebra T12 are distinctly thoracic, its inferior aspect has lumbar characteristics for articulation with vertebra L1. The abrupt transition allowing prim arily rotational movem ents with vertebra T11 while disallowing rotational m ovements with vertebral L1 m akes vertebra T12 especially susceptible to fracture.

TABLE 1.2

T8

Superior costal facet

T9 Inferior costal facet

T10 Spinous process

Inferior four thoracic vertebrae

T11

THORACIC VERTEBRAE

Pa rt

Distinctive Cha ra cteristics

Body

Heart-shaped; has one or two costal facets for articulation with head of rib

Mammillary

Vertebral foramen

Circular and smaller than those of cervical and lumbar vertebrae

Transverse

Transverse processes

Long and extend posterolaterally; length diminishes from T1 to T12; T1–T10 have transverse costal facets for articulation with a tubercle of ribs 1–10 (ribs 11 and 12 have no tubercle and do not articulate with a transverse process)

Articular processes

Superior articular facets directed posteriorly and slightly laterally; inferior articular facets directed anteriorly and slightly medially

Spinous process

Long and slopes postero-inferiorly; tip extends to level of vertebral body below

Processes: Accessory

B. Lateral View

T12

THORACIC SPINE

Back

15

Spinous process Transverse process

Lamina

Vertebral foramen

T1

Pedicle

T2

T3

T4

Vertebral body Superior four thoracic vertebrae (T1–T4)

T5

T6

T7

T8

Middle four thoracic vertebrae (T5–T8)

T9

C. Superior Views

Anterior Anterior longitudinal ligament Radiate ligament of head of rib

T10

T11

T12

Inferior four thoracic vertebrae (T9–T12)

Posterior Tubercle of 6th rib Costotransverse joint

Transverse process Superior costotransverse ligament Joint of head of rib Intra-articular ligament Joint of head of rib

D. Lateral View

Head of 7th rib Tubercle of 7th rib

THORACIC VERTEBRAE (continued )

1.12

C. Disarticulated thoracic vertebrae. The vertebral bodies increase in size as the vertebral colum n d escend s, each b earing an increasing am ount of weight transferred by the vertebra above. D. Intra- and extra-articular ligam ents of the costoverteb ral articulations. Typ ically, the head of each rib articulates with the b od ies of two ad jacent verteb rae and the IV d isc b etween them , and the tubercle of the rib articulates with the transverse p rocess of the inferior verteb ra.

Back

16

LUMBAR SPINE Pedicle Spinous process L1

Vertebral body

T12

P

DS

IV

L1

P Superior articular process

DS

IV

SP

L2

P

Transverse process L2

DS

IV

SP

L3

P Inferior articular facet

Superior vertebral notch

SP IA

L3

SP

IV

DS

P

L4

IV

DS

F P

Inferior vertebral notch

SP

L5

IV DS

L4

B. Lateral Radiograph

Inferior articular process

DS

L5 IA

L2

A. Lateral Views F

DS

1.13

LUMBAR VERTEBRAE TP

A, D, and E. Features. B, C, and F. Radiographs. G. Lam inectom y.

L3

TABLE 1.3

DS

LUMBAR VERTEBRAE SA

Pa rt

Distinctive Cha ra cteristics

Body

Massive; kidney-shaped when viewed superiorly

Vertebral

Triangular; larger than in thoracic vertebrae and foramen smaller than in cervical vertebrae

C. Oblique Radiograph

Transverse

Long and slender; accessory process on posterior surface of base of each transverse process

Key for B, C, and D

Articular processes

Superior articular facets directed posteromedially (or medially); inferior articular facets directed anterolaterally (or laterally); mammillary process on posterior surface of each superior articular process

Spinous process

Short and sturdy; thick, broad, and rectangular

F DS IA IV L

Zygapophysial (facet) joint Intervertebral disc space Inferior articular process Intervertebral foramen Lamina

P SA SP T12–L5 TP

L4

Pedicle Superior articular process Spinous process Vertebral bodies Transverse process

Back

LUMBAR SPINE Process: Spinous (SP) Mammillary (M) Accessory (A) Transverse (TP)

Superior articular process

M A TP

L1 SP

L1

L

Inferior articular process Lamina

F

Superior articular facet

Pedicle

17

L2

Vertebral canal

P Superior articular process Superior articular facet

IA

IA

F

SA

L3 L4 SP

L5

L4

Sacrum

Superior articular facet

L5 D. Superior View

Inferior articular process

E. Posterior View

F. Anteroposterior Radiograph

LUMBAR VERTEBRAE (continued ) Pedicle 2

Vertebral arch

1

Lamina

G. Superior View, Sites of Laminectomy (1 and 2)

1.13

A lam in e ct o m y is the surgical excision of one or m ore spinous processes and their supporting lam inae in a particular region of the vertebral colum n by transecting the interarticular part (Fig. 1.13G, 1). The term is also com m only used to denote the rem oval of m ost of the vertebral arch by transecting the pedicles (Fig. 1.13G, 2). Lam inectom ies p rovide access to the vertebral canal to relieve pressure on the sp inal cord or nerve roots, com m only caused by a tum or or herniated IV disc.

18

Back

LIGAMENTS AND INTERVERTEBRAL DISCS Superior vertebral notch Superior articular process

Intervertebral (IV) foramen

Intervertebral (IV) disc

Joint capsule of zygapophysial (facet) joint Ligamentum flavum Anulus fibrosus of IV disc (dissected to show lamellae)

Inferior articular facet

A. Lateral View Inferior vertebral notch Cauda equina Spinal ganglion in dural sleeve Posterior ramus of spinal nerve

Spinal nerve Recurrent meningeal nerve

Superior articular process

1.14

STRUCTURE AND INNERVATION OF INTERVERTEBRAL DISCS AND ZYGAPOPHYSIAL JOINTS

A. Intervertebral discs and intervertebral foram en. Sections have been rem oved from the super cial layers of the anulus brosus of the inferior IV d isc to show the change in direction of the bers in the concentric layers of the anulus. Note that the IV discs form the inferior half of the anterior boundary of the IV foram en. B. Innervation of zygapophysial joints and the anulus brosus of IV discs. When the zyg ap o p h ysial jo in t s are in jure d or develop osteophytes during aging (osteoarthritis), the related spinal nerves are affected. This causes pain along the distribution pattern of the derm atom es and spasm in the m uscles derived from the associated m yotom es. Denervation of lum bar zygap ophysial joints is a procedure that m ay be used for treatm ent of back pain caused by disease of these joints. The denervation process is directed at the articular branches of two adjacent posterior ram i of the spinal nerves because each joint receives innervation from both the nerve exiting that level and the superjacent nerve.

Articular branches of posterior ramus

Anterior ramus of spinal nerve Anulus fibrosus

Zygapophysial joint Articular branches of posterior ramus

Branch to anulus fibrosus of IVdisc

Transverse process Medial branch of posterior ramus Muscular branch

B. Left Posterolateral View

Lateral branch of posterior ramus Muscular branch

Cutaneous branch

Back

LIGAMENTS AND INTERVERTEBRAL DISCS

19

Anulus fibrosus

Hyaline end-plate (nucleus pulposus removed)

Internal vertebral (epidural) venous plexus Cauda equina

Subarachnoid space

Joint capsule of zygapophysial (facet) joint

Synovial fold Superior articular facet

Ligamentum flavum Interspinous ligament

Supraspinous ligament

C. Transverse Section, Superior View

Inferior vena cava Aorta L4–L5 Intervertebral (IV) disc

Psoas major

Zygapophysial (facet) joints

L3–4 IVdisc

Anulus fibrosus

Superior articular process of L4 vertebra

Superior articular process of L3 vertebra

Cauda equina in lumbar cistern

Lamina (LA)

Inferior articular process of L5 vertebra Facet joint

LA

LA SP

Spinous process (SP)

D. Transverse (Axial) CT Image

Facet joint Inferior articular process of L4 vertebra

E. Transverse (Axial) MRI

STRUCTURE AND INNERVATION OF INTERVERTEBRAL DISCS AND ZYGAPOPHYSIAL JOINTS (continued ) C. Tran sve rse se ct io n . The nucleus pulposus has been rem oved, and the cartilaginous epiphysial p late exposed. There are fewer rings of the anulus brosus posteriorly, and consequently, this

Nucleus pulposus

1.14

portion of the anulus brosus is thinner. The ligam entum avum , interspinous, and supraspinous ligam ents are continuous. D. CT im age of L4/ L5 IV disc. E. MRI.

20

Back

LIGAMENTS AND INTERVERTEBRAL DISCS

Superior articular process

T9 vertebra Zygapophysial (facet) joint

Pedicle (cut) Ligamentum flavum

Lamina

Pedicle (cut)

Posterior longitudinal ligament Anulus fibrosus

Nucleus pulposus

Body

Anterior longitudinal ligament

Intervertebral disc

A. Anterior View

1.15

INTERVERTEBRAL DISCS: LIGAMENTS AND MOVEMENTS

A. Anterior longitudinal ligam ent and ligam enta ava. The pedicles of the superior vertebrae were sawed through to show the ligam enta ava. • The anterior and p osterior longitudinal ligam ents are ligam ents of the vertebral bodies; the ligam enta ava are ligam ents of the vertebral arches. • The anterior longitudinal ligam ent consists of b road , strong , brous bands that are attached to the IV discs and vertebral

bodies anteriorly and are perforated by the foram ina for arteries and veins p assing to and from the vertebral b odies. • The ligam enta ava, com posed of elastic b ers, extend between adjacent lam inae and converge in the m edian p lane. They extend laterally to blend with the joint capsule of the zygapophysial joints.

LIGAMENTS AND INTERVERTEBRAL DISCS

Back

21

Anulus fibrosus Pedicle (cut)

Intervertebral vessels

Posterior longitudinal ligament

B. Posterior View

Nucleus pulposus

Vertebral body

Vertebral body Disc Vertebral body

Anulus fibrosus

Lateral view Recumbent

C.

Lateral view Extension

Lateral view Erect (weight bearing)

Lateral view Flexion

Anterior view Lateral flexion

INTERVERTEBRAL DISCS: LIGAMENTS AND MOVEMENTS (continued ) B. Posterior lon g itud in al lig am en t. Th e p ed icles of verteb ra T9– T11 were sawed throug h and the verteb ral arch rem oved to show the p osterior asp ect of th e verteb ral b od ies. Th e p osterior long itud inal lig am ent is a narrow b and p assing from d isc to d isc,

Anterior view Tension

Anterior view Rotation (torsion)

1.15

sp an n in g th e p osterior surfaces of th e verteb ral b od ies. C. IV d isc d uring load ing and m ovem ent. The m ovem ent or load ing of th e IV d isc ch an g es its sh ap e an d th e p osition of th e n ucleus p ulp osus.

22

Back

LIGAMENTS AND INTERVERTEBRAL DISCS

Median section

L1

Posterior longitudinal ligament

L1 L1

L2

Nucleus pulposus protruding posteriorly

L3 Ligamentum flavum

L4

L2 L2

Interspinous ligament

Cavity for nucleus pulposus Intervertebral foramen Anulus fibrosus Anterior longitudinal ligament Hyaline plate

L3 L3

Supraspinous ligament Spinal nerve

Nucleus pulposus protruding into vertebral bodies

Anterior and posterior nerve roots Bursa

Canal for basivertebral vein Median Section

1.16

L4 L4

Arachnoid mater lining dura mater

LUMBAR REGION OF VERTEBRAL COLUMN

The nucleus p ulp osus of the norm al disc between vertebrae L2 and L3 has been rem oved from the enclosing anulus brosus. The bursa between L3 and L4 spines is presum ably the result of habitual hyperextension, which brings the lum bar spines into contact. The nucleus pulposus of the disc between L1 and L2 has herniated posteriorly through the anulus. He rn iat io n or p ro t rusio n o f t h e g e lat in o us n ucle us p ulp o sus into or through the anulus

brosus is a well-recognized cause of low back and lower lim b pain. If degeneration of the p osterior longitudinal ligam ent and wearing of the anulus brosus has occurred, the nucleus p ulp osus m ay herniate into the vertebral canal and com press the spinal cord or nerve roots of spinal nerves in the cauda equina. Herniations usually occur posterolaterally, where the anulus is relatively thin and d oes not receive supp ort from the ligam ents.

BONES, JOINTS, AND LIGAMENTS OF PELVIC GIRDLE

Back

23

L5 spinous process 18 1 2

3 Anterior and posterior sacro-iliac joint lines

17 16

4 15 5 14 6

13

7 12 8

A. Anteroposterior Radiograph

11

10

9

Iliac crest (18)

Ala of sacrum (1) Ilium (2) Sacro-iliac joint (3)

Anterior superior iliac spine (17) Anterior inferior iliac spine (16)

Ischial spine (4) Superior pubic ramus (5)

Greater trochanter (14) Hip joint (head of femur in acetabular fossa) (15)

Intertrochanteric line (6)

Neck of femur (13) Ischial tuberosity (8) Lesser trochanter (12)

B. Anterior View

Pubic tubercle (11)

Body of pubis

Ischiopubic ramus (9)

Obturator foramen (7)

Pubic symphysis (10)

PELVIS A. Rad iograph of p elvis. B. Bony p elvis with articulated fem ora.

1.17

Back

24

BONES, JOINTS, AND LIGAMENTS OF PELVIC GIRDLE

Iliac crest

Iliac fossa

Anterior superior iliac spine

Iliac tuberosity

Posterior superior iliac spine

Anterior inferior iliac spine Arcuate line

Auricular surface of ilium

Pecten pubis

Greater sciatic notch

Iliopubic eminence

Posterior inferior iliac spine

Body of ischium Superior pubic ramus Body of pubis

Ischial spine Obturator foramen

Lesser sciatic notch Superior articular process

Inferior pubic ramus* Ischial tuberosity

A. Medial View

Ramus of ischium*

*Ischiopubic ramus

Body of S1 segment of sacrum

Sacral tuberosity Lateral sacral crest

Ilium Auricular surface of sacrum Cornua of sacrum and coccyx Pubis

Transverse process of coccyx

1 2

Ischium

B. Medial View

1.18

C. Lateral View

3

4

Tip of coccyx

HIP BONE, SACRUM, AND COCCYX

A. Features of hip bone. B. Ilium , ischium , and pubis. C. Sacrum and coccyx. • Each hip bone consists of three bones: ilium , ischium , and p ubis. • Anterosup eriorly, the auricular, ear-shaped surface of the sacrum articulates with the auricular surface of the ilium ; the sacral and

iliac tuberosities are for the attachm ent of the posterior sacroiliac and interosseous sacro-iliac ligam ents. • The ve sacral vertebrae are fused to form the sacrum .

Back

BONES, JOINTS, AND LIGAMENTS OF PELVIC GIRDLE

25

Superior articular process

Sacral canal

Ala Ala

Body of S1 vertebra

Promontory of sacrum S2 Anterior sacral foramina

S3 Lateral mass S4 Inferolateral angle S5 Apex of sacrum

Transverse process of coccyx 1

A. Anterior View

2 3 4

Base of coccyx

1

2 Apex of coccyx 3 Superior sacral notch

Sacral canal

4

Superior articular facet

5

Median crest

Auricular surface

C. Anterior View

Sacral tuberosity

Intermediate crest

Posterior sacral foramina

Lateral crest

Sacral hiatus

Inferolateral angle

Sacrococcygeal notch Cornua of sacrum and coccyx Transverse process of coccyx

B. Posterior View

Apex of coccyx

SACRUM AND COCCYX A. Pelvic (anterior) surface. B. Dorsal (posterior) surface. C. Sacrum in youth. • The bodies of the ve sacral vertebrae are dem arcated in the m ature sacrum by four transverse lines ending laterally in four pairs of anterior sacral foram ina ( A) . The coccyx has four vertebrae

1.19 (segm ents)—the rst having a p air of transverse processes and a pair of cornua (horns). • The ossi cation and fusion of the sacral vertebrae m ay not be com plete until age 35.

Back

26

BONES, JOINTS, AND LIGAMENTS OF PELVIC GIRDLE

Transverse process of L5 vertebra

Anterior longitudinal ligament

Iliac crest Iliolumbar ligament Ilium

L5/S1 intervertebral disc

Greater sciatic foramen

Anterior sacro-iliac ligament

Sacrotuberous ligament Sacrospinous ligament

A. Anterior View

1.20

Sacrum

Coccyx Anterior sacrococcygeal ligament

LUMBAR AND PELVIC LIGAMENTS

The anterior sacro-iliac ligam ent is part of the brous cap sule of the sacro-iliac joint anteriorly and spans between the lateral aspect of the sacrum and the ilium , anterior to the auricular surfaces. During p re g n an cy, the pelvic joints and ligam ents relax, and pelvic m ovem ents increase. The sacro-iliac interlocking m echanism is less effective because the relaxation perm its greater rotation of

the pelvis and contributes to the lordotic posture often assum ed during pregnancy with the change in the center of gravity. Relaxation of the sacro-iliac joints and pubic sym physis perm its as m uch as 10% to 15% increase in diam eters (m ostly transverse), facilitating passage of the fetus through the pelvic canal. The coccyx is also allowed to m ove posteriorly.

Back

BONES, JOINTS, AND LIGAMENTS OF PELVIC GIRDLE

27

Transverse process of L5 vertebra Supraspinous ligament

Iliolumbar ligament

Posterior sacro-iliac ligament

Ilium

Posterior superior iliac spine Sacrospinous ligament Greater sciatic foramen Ischial spine

Posterior sacrococcygeal ligaments

B. Posterior View

Sacrotuberous ligament

LUMBAR AND PELVIC LIGAMENTS (continued ) • The sacrotuberous ligam ents attach the sacrum , ilium , and coccyx to the ischial tuberosity; the sacrospinous ligam ents unite the sacrum and coccyx to the ischial spine. The sacrotuberous and sacrospinous ligam ents convert the sciatic notches of the hip bones into greater and lesser sciatic foram ina. • The bers of the p osterior sacro-iliac ligam ent vary in obliquity; the superior bers are shorter and lie between the ilium and

Lesser sciatic foramen Ischial tuberosity

1.20 superior part of the sacrum ; the longer, obliquely oriented inferior bers span between the posterior superior iliac spine and the inferior part of the sacrum . • The iliolum bar ligam ents unite the ilia and transverse processes of L5.

Back

28

BONES, JOINTS, AND LIGAMENTS OF PELVIC GIRDLE

Interosseous sacro-iliac Sacral S1 Ala of Iliacus Psoas ligament canal nerve sacrum

Ilium

Sacro-iliac joint Sacral tuberosity

Auricular surface Auricular surface

Iliac tuberosity

Hip bone, medial view

Sacrum, lateral view

A.

C. Transverse (Axial) CT Image

Ilium

Sacral canal

Posterior sacro-iliac ligament Interosseous sacro-iliac ligament Sacro-iliac joint Anterior sacro-iliac ligament

Ala of sacrum Sacrum

Posterior joint line Anterior joint line

Sacrospinous ligament Ischial spine

Sacral foramina

Sacrotuberous ligament

Coccyx Lateral mass of sacrum

B. Coronal Section

1.21

D. Anteroposterior Radiograph

ARTICULAR SURFACES OF SACRO-ILIAC JOINT AND LIGAMENTS

A. Articular surfaces. Note the auricular surface (blue) of the sacrum and hip bone and the roughened areas superior and posterior to the auricular areas for the attachm ent of the interosseous sacro-iliac ligam ent. B. Sacro-iliac ligam ents. The interosseous sacro-iliac ligam ent consists of short bers connecting the sacral tuberosity to the iliac

tuberosity. C. CT im age. The sacro-iliac joint is indicated (arrows). Note that the articular surfaces of the ilium and sacrum have irregular shapes that result in partial interlocking of the bones. D. Radiograph. Due to the oblique placem ent of the sacro-iliac joints, the anterior and posterior joint lines appear separately.

ANOMALIES OF VERTEBRAE 1st sacral vertebra (lumbarized)

1

Back

Unfused posterior arch

7 Synostosis

2

29

1 2

Atlas

Bony spur (osteophyte)

Axis (C2)

3

3 4

C3

Hemivertebra

5

4

B. Inferior View

5

C. Lateral View

D. Superior View

6

E. Anterior View

Coccyx Spinous process of L4

A. Anterior View

L5

L5 Defect (spondylolysis) L5 L5 Anterior displacement (spondylolisthesis)

Posterior View

Sacrum Sacral canal

F. Sagittal Section

L4 Defect

Pedicle

L5

S1

Interarticular part (pars interarticularis) Sacral canal

Superior articular process Intact pars at L4 Inferior articular process Pars defect at L5

G. Lateral Radiograph

H. Oblique Radiograph

ANOMALIES OF VERTEBRAE AND SPONDYLOLYSIS AND SPONDYLOLISTHESIS A. Transitional lum bosacral vertebra. Here, the 1st sacral vertebra is partly free (lum barized). Not uncom m only, the 5th lum bar vertebra m ay be partly fused to the sacrum (sacralized). B. Unfused posterior arch of the atlas. C. Synostosis (fusion) of vertebrae C2 (axis) and C3. D. Bony spurs. Sharp bony spurs m ay grow from the lam inae inferiorly into the ligam enta ava. E. Hem ivertebra. The entire right half of vertebra T3 and the corresponding rib are absent. The left lam ina and the spine are fused with those of T4, and the left IV foram en is reduced in size. Observe the associated scoliosis (lateral curvature of the spine). F. Articulated and isolated spondylolytic L5

1.22

vertebra. The vertebra has an oblique defect (spondylolysis) through the interarticular part (pars interarticularis). Also, the vertebral body of L5 has slipped anteriorly (spondylolisthesis). G. and H. Radiographs. The posterior vertebral m argins of L5 (dotted line) and the sacrum shows the anterior displacem ent of L5 (arrow) (G). Note the superim posed outline of a dog: the nose is the transverse process, the eye is the pedicle, the neck is the interarticular part and the ear is the superior articular process ( H). The lucent (dark) cleft across the “neck” of the dog is the sp on d ylolysis; the anterior displacem ent (arrow) is the sp on d ylolist h esis.

Back

30

MUSCLES OF BACK

Site of nuchal ligament

Descending (superior) part of trapezius

Spinal (posterior) part of deltoid

Transverse (middle) part of trapezius Teres major

Ascending (inferior) part of trapezius

Latissimus dorsi

External oblique

Erector spinae

Posterior median furrow

Gluteus medius

Gluteus maximus

Site of posterior superior iliac spine (PSIS)

Intergluteal cleft

Posterior View

1.23

SURFACE ANATOMY OF BACK

• The arm s are abducted, so the scapulae have rotated superiorly on the thoracic wall. • The latissim us dorsi and teres m ajor m uscles form the posterior axillary fold. • The trap ezius m uscle has three p arts: descending, transverse, and ascending.

• Note the deep m edian furrow that separates the longitudinal bulges form ed by the contracted erector spinae group of m uscles. • Dim p les (d ep ressions) ind icate the site of the p osterior sup erior iliac sp in es, wh ich usually lie at th e level of th e sacroiliac join ts.

MUSCLES OF BACK

Back

31

Occipitalis Occipital artery Occipital lymph node Descending (superior) part of trapezius

Greater occipital nerve (posterior ramus of C2 spinal nerve) 3rd occipital nerve (posterior ramus of C3) Lesser occipital nerve (anterior ramus of C2)

Levator scapulae Rhomboid minor Rhomboid major

Cutaneous branches of posterior rami Transverse (middle) part of trapezius

Deltoid

Ascending (inferior) part of trapezius Triangle of auscultation

Subtrapezial plexus (spinal accessory nerve [CN XI] and branches of C3, C4 anterior rami)

Cutaneous branches of posterior rami

Trapezius

Latissimus dorsi

Posterior branches of lateral cutaneous branches External oblique Thoracolumbar fascia Gluteal fascia (covering gluteus medius)

Lateral cutaneous branch of iliohypogastric nerve (anterior ramus of L1) Cutaneous branches of posterior rami of L1 to L3 (superior clunial nerves)

Gluteus maximus

Posterior View

SUPERFICIAL MUSCLES OF BACK The left trap ezius m uscle is re ected . Observe two layers: the trapezius and latissim us dorsi m uscles, and the levator scapulae and

1.24 rhom boids m inor and m ajor. These axio-app endicular m uscles help attach the upper lim b to the trunk.

32

Back

MUSCLES OF BACK

Nuchal ligament Sternocleidomastoid Splenius Trapezius Levator scapulae Posterior scalene

Semispinalis capitis Sternocleidomastoid Splenius Levator scapulae Rhomboid minor

Serratus posterior superior Trapezius (cut surface) Rhomboid minor

Deltoid

Rhomboid major Rhomboid major

Teres major Serratus anterior

Serratus anterior 8th rib

Thoracolumbar fascia

Angle of rib

10th rib Serratus posterior inferior (aponeurosis)

External oblique

Serratus posterior inferior (belly)

Latissimus dorsi External oblique

Internal oblique Aponeurosis of internal oblique

Lumbar triangle Gluteal fascia (covering gluteus medius)

Iliac crest

Gluteus maximus

Posterior View

1.25

INTERMEDIATE MUSCLES OF BACK

The trapezius and latissim us dorsi m uscles are largely cut away on both sides. The left rhom boid m uscles have been re ected, allowing the vertebral border of the scapula to be raised from the thoracic wall. The serratus posterior superior and inferior form the interm ediate layer of m uscles, passing from the vertebral spines to the ribs; the

two m uscles slope in opposite directions and are accessory m uscles of respiration. The thoracolum bar fascia extends laterally to the angles of the ribs, becom ing thin superiorly and passing deep to the serratus posterior superior m uscle. The fascia gives attachm ent to the latissim us dorsi and serratus posterior inferior m uscles (see Fig. 1.30).

MUSCLES OF BACK

Sternocleidomastoid

Back

33

Semispinalis capitis Sternocleidomastoid

Splenius capitis

Levator scapulae Levator scapulae Iliocostalis cervicis

Splenius cervicis

Longissimus thoracis

Spinalis Three columns Longissimus of erector spinae

Iliocostalis thoracis Spinalis

Iliocostalis

Posterior rami of spinal nerves 10th rib

Iliocostalis lumborum Aponeurosis of transversus abdominis

Gluteal fascia (covering gluteus medius)

Gluteus maximus Posterior View

DEEP MUSCLES OF BACK: SPLENIUS AND ERECTOR SPINAE Th e rig h t erector sp in ae m uscles are in situ, lyin g b etween th e sp in ous p rocesses m ed ially an d th e an g les of th e rib s laterally. Th e erector sp in ae are sp lit in to th ree lon g itud inal colum n s: iliocostalis laterally, lon g issim us in th e m id d le, an d sp in alis

1.26

m ed ially. Th e left lon g issim us m uscle is p ulled laterally to sh ow th e in sertion in to th e tran sverse p rocesses an d rib s; n ot sh own h ere are its exten sion s to th e n eck an d h ead , lon g issim us cervicis an d cap itis.

34

Back

MUSCLES OF BACK

Splenius capitis (cut end) Semispinalis capitis

Semispinalis capitis

Splenius capitis and cervicis (cut edge)

Suboccipital triangle Longissimus capitis Splenius cervicis (cut end) Semispinalis cervicis

Semispinalis thoracis Spinous process

Levatores costarum Posterior ramus of spinal nerve

Transverse process Multifidus thoracis

External intercostal

Middle layer of thoracolumbar fascia

Erector spinae (cut end)

Gluteal fascia (covering gluteus medius)

Multifidus lumborum Gluteus maximus

Posterior View

1.27

DEEP MUSCLES OF BACK: SEMISPINALIS AND MULTIFIDUS

• The sem isp inalis, m ulti dus, and rotatores m uscles constitute the transversospinalis group of deep m uscles. In general, their bundles pass obliquely in a sup erom edial direction, from transverse processes to spinous processes in successively deeper layers. The bundles of sem isp inalis sp an app roxim ately ve interspaces, those of m ulti dus, ap proxim ately three, and those of rotatores, one or two.

• The sem ispinalis (thoracis, cervicis, and capitis) m uscles span the lower thoracic region to the cranium . • The m ulti dus m uscle extends from the sacrum to the spinous process of the axis. In the lum bosacral region, it em erges from the aponeurosis of the erector spinae and extends from the sacrum , and m am m illary processes of the lum bar vertebrae, to insert into spinous processes approxim ately three segm ents higher.

MUSCLES OF BACK

Back

35

Superior costotransverse ligament Transverse process Posterior ramus of spinal nerve Neck of rib Rotatores brevis Tubercle of rib Rotatores longus

External intercostal Superior costotransverse ligament Levator costarum longus

Levator costarum brevis Lateral costotransverse ligaments

Dura mater

Spinal cord

Posterior costotransverse ligament

Posterior longitudinal ligament

Posterior View

ROTATORES AND COSTOTRANSVERSE LIGAMENTS • Of the three layers of transversospinalis muscles, the rotatores are the deepest and shortest. They pass from the root of one transverse process superomedially to the junction of the transverse process and lamina of the vertebra above. Rotatores longus span two vertebrae. • The levatores costarum pass from the tip of one transverse process inferiorly to the rib below (brevis); som e span two ribs (longus).

1.28 • The p osterior ram us p asses posterior to the superior costotransverse lig am ent. • The lateral costotransverse ligam ent is strong and joins the tubercle of the rib to the tip of the transverse process. It form s the posterior aspect of the joint capsule of the costotransverse joint.

Back

36

MUSCLES OF BACK

Spinous processes:

Transverse processes:

T 11

Levator costarum

Lumbar rib

T 12

Intertransversarii

L1

Lumbocostal ligament 12th rib

L1

L2

Posterior layer of thoracolumbar fascia (cut edge)

Transverse process Middle layer of thoracolumbar fascia

Middle layer of thoracolumbar fascia

L2

L3

Posterior ramus of spinal nerve

L3 L4

Quadratus lumborum

Posterior layer of thoracolumbar fascia

External oblique Iliolumbar ligament Aponeurotic origin of erector spinae

L4

L5

Iliac crest

L5 S1

Posterior superior iliac spine

Multifidus

Aponeurosis of erector spinae

Posterior View

1.29

BACK: MULTIFIDUS, QUADRATUS LUMBORUM, AND THORACOLUMBAR FASCIA

After rem oval of right erector spinae at the L1 level, the m iddle layer of thoracolum bar fascia is seen to extend from the tip of each lum bar transverse process in a fan-shaped m anner. A short lum bar rib is present at the level of L1.

After rem oval of the left posterior and m iddle layers of thoracolum bar fascia, the lateral bord er of the quad ratus lum borum m uscle is oblique, and the m edial border is in continuity with the intertransversarii.

Back

MUSCLES OF BACK

Lumbar intervertebral disc

Anulus fibrosus Nucleus pulposus

37

Vertebral canal Psoas fascia Ligamentum flavum

Psoas

Interspinous ligament Anterior layer of thoracolumbar fascia (quadratus lumborum fascia) Aponeurosis of transversus abdominis

Internal oblique

External oblique

Latissimus dorsi Quadratus lumborum

Iliocostalis lumborum Longissimus

Intertransversarius

Interspinalis

Multifidus

Erector spinae, aponeurosis of origin

Tip of transverse process

Layers of Middle thoracolumbar Posterior fascia

Transverse Section (Dissected), Superior View

TRANSVERSE SECTION OF BACK MUSCLES AND THORACOLUMBAR FASCIA • The left m uscles are seen in their fascial sheaths or com partm ents; the right m uscles have b een rem oved from their sheaths. • The aponeurosis of transversus abdom inis and posterior aponeurosis of internal obliq ue m uscles split into two strong sheets, the m iddle and p osterior layers of thoracolum bar fascia. The anterior layer of thoracolum bar fascia is the deep fascia of the q uadratus lum borum (quadratus lum borum fascia). The posterior layer of the thoracolum bar fascia provides proxim al attachm ent for

1.30

the latissim us dorsi m uscle and, at a higher level, the serratus posterior inferior m uscle. Back st rain is a com m on back problem that usually results from extrem e m ovem ents of the vertebral colum n, such as extension or rotation. Back strain refers to som e stretching or m icroscopic tearing of m uscle bers and/ or ligam ents of the back. The m uscles usually involved are those producing m ovem ents of the lum bar IV joints.

Back

38

MUSCLES OF BACK

Transversospinalis

Multifidus

Mastoid process

Transverse process of C4

Rotatores Semispinalis

Angle of 2nd rib

Spinalis Longissimus

Erector spinae

Longissimus capitis

Iliocostalis cervicis

Iliocostalis

Angle of rib Longissimus thoracis

Iliocostalis thoracis Serratus posterior

Longissimus Iliocostalis lumborum

Latissimus dorsi

Thoracic spinous process

Trapezius

Iliocostalis

A. Transverse Section

Iliac crest

Key for A: Back muscles Superficial extrinsic Intermediate extrinsic

Erector spinae (intermediate intrinsic) Transversospinales (deep intrinsic)

Posterior superior iliac spine

B.

C.

Posterior Views Nuchal ligament

Mastoid process Spinalis cervicis

Nuchal ligament Splenius capitis

Spinous process (T1)

1.31

SUPERFICIAL AND INTERMEDIATE LAYERS OF INTRINSIC BACK MUSCLES

3

Spinalis thoracis

A. Transverse section. The erector spinae consists of three colum ns and the transversospinalis consists of three layers. B. Iliocostalis. C. Longissim us. D. Spinalis. E. Splenius capitis and cervicis.

Splenius cervicis Spinous process (T4)

Spinalis

D. TABLE 1.4

2

Spinous process (T6)

Spinous process (L2)

E.

SUPERFICIAL AND INTERMEDIATE LAYERS OF INTRINSIC BACK MUSCLES

Muscles Supe r cial laye r Splenius

Int e rm e diat e laye r Erector spinae

Caudal (Inferior) Attachment

Rostra l (Superior) Atta chment

Nuchal ligament and spinous processes of C7–T6 vertebrae

Splenius capitis: bers run superolaterally to mastoid process of temporal bone and lateral third of superior nuchal line of occipital bone Splenius cervicis: posterior tubercles of transverse processes of C1– C3/C4 vertebrae

Arises by a broad tendon from posterior part of iliac crest, posterior surface of sacrum, sacral and inferior lumbar spinous processes, and supraspinous ligament

Iliocostalis (lumborum, thoracis, and cervicis): bers run superiorly to angles of lower ribs and cervical transverse processes Longissimus (thoracis, cervicis, and capitis): bers run superiorly to ribs between tubercles and angles to transverse processes in thoracic and cervical regions, and to mastoid process of temporal bone Spinalis (thoracis, cervicis, and capitis): bers run superiorly to spinous processes in the upper thoracic region and to skull

Nerve Supply

Ma in Actions Acting unilaterally: laterally ex neck and rotate head to side of active muscles Acting bilaterally: extend head and neck

Posterior rami of spinal nerves

Acting unilaterally: laterally bend vertebral column to side of active muscles Acting bilaterally: extend vertebral column and head; as back is exed, control movement by gradually lengthening their bers

Back

MUSCLES OF BACK Superior nuchal line

External occipital protuberance

Mastoid process

Obliquus capitis superior*

Semispinalis capitis Semispinalis thoracis

Cervical interspinales

Semispinalis capitis Multifidus

Cervical intertransversarii

Spinalis cervicis

Rectus capitis posterior major*

39

Obliquus capitis inferior* Rotatores

Rotatores

Levatores costarum

Spinalis thoracis Levatores costarum

Lumbar interspinales Lumbar intertransversarii

B. Multifidus Multifidus

Lumbar intertransversarii

C.

Posterior Views

D.

DEEP LAYER OF INTRINSIC BACK MUSCLES

A.

1.32

A. Overview. B. Sem ispinalis. C. Multi dus and rotatores. D. Interspinalis, intertransversarii, and levatores costarum .

TABLE 1.5 Muscles De e p laye r Transversospinalis

DEEP LAYERS OF INTRINSIC BACK MUSCLES Ca uda l (Inferior) Atta chment

Rostra l (Superior) Atta chment

Semispinalis: arises from thoracic and cervical transverse processes

Semispinalis: thoracis, cervicis, and capitis: bers run superomedially and attach to occipital bone and spinous processes in thoracic and cervical regions, spanning four to six segments Multi dus (lumborum, thoracis, and cervicis): bers pass superomedially to spinous processes, spanning two to four segments

Multi dus: arises from sacrum and ilium, transverse processes of T1–L5, and articular processes of C4–C7 Rotatores: arise from transverse processes of vertebrae; best developed in thoracic region Mino r deep layer Interspinales

a

Rotatores (thoracis and cervicis): Pass superomedially and attach to junction of lamina and transverse process of vertebra of origin or into spinous process above their origin, spanning one to two segments

Nerve Supply a

Posterior rami of spinal nerves

Ma in Actions Ext e nsio n Semispinalis: extends head and thoracic and cervical regions of vertebral column and rotates them contralaterally Multifidus: stab ilizes vertebrae during local m ovem ent of vertebral colum n Rotatores: stabilize vertebrae and assist with local extension and rotary movements of vertebral column; may function as organ of proprioception

Superior surfaces of spinous processes of cervical and lumbar vertebrae

Inferior surfaces of spinous processes of vertebrae superior to vertebrae of origin

Intertransversarii

Transverse processes of cervical and lumbar vertebrae

Transverse processes of adjacent vertebrae

Posterior and anterior rami of spinal nerves

Aid in lateral exion of vertebral column Acting bilaterally: stabilize vertebral column

Levatores costarum

Me dial at t achm e nt : tips of transverse processes of C7 and T1–T11 vertebrae

Lat e ral at t achm e nt : pass inferolaterally and insert on rib between its tubercle and angle

Posterior rami of C8–T11 spinal nerves

Elevate ribs, assisting inspiration Assist with lateral exion of vertebral column

Most back muscles are innervated by posterior rami of spinal nerves, but a few are innervated by anterior and posterior rami.

Aid in extension and rotation of vertebral column

40

Back

SUBOCCIPITAL REGION Superior nuchal line

Epicranial aponeurosis Occipitalis

Occipital artery External occipital protuberance

Obliquus capitis superior Digastric

Greater occipital nerve (C2)

Longissimus capitis

Obliquus capitis superior

Semispinalis capitis

Rectus capitis posterior minor

Suboccipital nerve (C1) Obliquus capitis inferior

Posterior tubercle of atlas Semispinalis capitis

Posterior rami C2

Rectus capitis posterior major Spinous process of axis Longissimus capitis

Posterior rami C3

Posterior rami C4 Interspinales Deep cervical vein Semispinalis cervicis

Spinous process of C7 vertebra

A. Posterior View

Intertransversarius Middle scalene Vertebral artery

Internal jugular vein

Anterior ramus of C2 spinal nerve

Levator scapulae Splenius cervicis

Axis

1.33

Sternocleidomastoid

SUBOCCIPITAL REGION I

A. Super cial dissection. The trapezius, sternocleidom astoid, and splenius m uscles are rem oved. The right sem isp inalis cap itis m uscle is cut and re ected laterally. B. Transverse section at the level of the axis. • The sem isp inalis cap itis, the great extensor m uscle of the head and neck, form s the posterior wall of the suboccipital region. It is pierced by the greater occipital nerve (posterior ram us of C2) and has free m edial and lateral borders at this level. • The greater occip ital nerve, when followed caudally, leads to the inferior border of the obliq uus capitis inferior m uscle, around which it turns. Following the inferior border of the obliquus capitis inferior m uscle m edially from the nerve leads to the spinous process of the axis; followed laterally, this leads to the transverse p rocess of the atlas.

Longissimus capitis Greater occipital nerve (C2) Splenius capitis Rectus capitis posterior major Semispinalis capitis Descending (superior) part of trapezius Posterior ramus (C3) Nuchal ligament

B. Transverse Section

Back

SUBOCCIPITAL REGION

41

External occipital protuberance Occipital artery and vein Posterior auricular vein Rectus capitis posterior minor Occipital veins

Splenius capitis (cut end) Rectus capitis posterior major

Nuchal ligament

Obliquus capitis superior

Descending branch of occipital artery

Suboccipital nerve (C1) Posterior tubercle of atlas

Posterior arch of atlas

Greater occipital nerve (C2)

Obliquus capitis inferior

Spinous process of axis

Greater occipital nerve (C2) Longissimus capitis

Semispinalis capitis

Semispinalis cervicis Posterior ramus of C3 spinal nerve Semispinalis capitis Deep cervical vein and artery

Nuchal ligament

Posterior ramus of C4

Splenius capitis

Posterior ramus of C5 Semispinalis cervicis Trapezius

A. Posterior View

Rectus capitis lateralis Longissimus capitis Foramen magnum

Posterior belly of digastric Splenius capitis Posterior atlanto-occipital membrane Tendon of sternocleidomastoid Obliquus capitis superior Rectus capitis posterior major Rectus capitis posterior minor Nuchal ligament Semispinalis capitis Tendon of trapezius

B. Inferior View

SUBOCCIPITAL REGION II

1.34

A. Deep dissection. The left sem isp inalis cap itis is re ected and the right m uscle is rem oved; neck is exed. B. Muscle attachm ents on the inferior aspect of the cranium . • The suboccipital region contains four pairs of structures: two straight m uscles, the rectus capitis posterior m ajor and m inor; two oblique m uscles, the obliquus capitis superior and obliq uus capitis inferior; two nerves (posterior ram i), C1 suboccip ital (m otor) and C2 greater occipital (sensory); and two arteries, the occipital and vertebral. • The nuchal ligam ent, which represents the cervical part of the supraspinous ligam ent, is a m edian, thin, brous partition attached to the spinous processes of cervical vertebrae and the external occipital protuberance.

42

Back

SPINAL CORD AND MENINGES

Foramen magnum Spinal accessory nerve (CN XI) C2 spinal nerve Arachnoid mater (lining dura mater) Spinal (posterior root) ganglion Spinal cord (cervical enlargement) Pedicle (cut)

Posterior rootlets C8 spinal nerve

External intercostal Denticulate ligament

Intercostal nerve T5 spinal nerve Parietal pleura Intercostal nerve (anterior ramus)

Rami communicantes

LEFT

RIGHT

Sympathetic trunk

Posterior ramus

Innermost intercostal Spinal cord (lumbar enlargement)

L1 spinal nerve

Conus medullaris

Transversus abdominis Cauda equina

Psoas major Termination of dural sac

Cut edge of sacrum revealing sacral canal Anterior sacral foramina transmitting anterior rami Filum terminale externum Posterior View

1.35

SPINAL CORD IN SITU

SPINAL CORD AND MENINGES

Back

43

Posterior rootlets Anterior rootlets Denticulate ligament

Denticulate ligament Anterior root

Posterior rootlets (cut) Spinal cord

Dura mater

Arachnoid mater

A. Posterior View

Prominence due to dens of axis Edge of foramen magnum

Jugular tubercle

Glossopharyngeal nerve (CN IX) Hypoglossal nerve (CN XII) Hypoglossal nerve (CN XII) Vertebral artery

Spinal accessory nerve (CN XI) Anterior rootlets of C1 spinal nerve

Spinal cord

Denticulate ligament Posterior rootlets of C2 spinal nerve

B. Superior View

SPINAL CORD AND MENINGES A. Dural sac cut open. The denticulate ligam ent anchors the cord to the dural sac between successive nerve roots by m eans of strong, toothlike processes. The anterior nerve roots (rootlets) lie anterior to the denticulate ligam ent, and the posterior nerve roots (rootlets)

1.36 lie posterior to the ligam ent. B. Structures of vertebral canal seen through foram en m agnum . The spinal cord, vertebral arteries, spinal accessory nerve (CN XI), and m ost superior part of the denticulate ligam ent pass through the foram en m agnum within the m eninges.

44

Back

SPINAL CORD AND MENINGES

Pedicle (cut end) Anterior ramus

L2 spinal nerve

Posterior ramus Body of vertebra Intervertebral disc Dura mater Spinal ganglion (dorsal root) Spinal nerves: L5

S1 Inferior end of dural sac S2

Spinal ganglion of S2 Posterior ramus spinal nerve

S3

S4

Anterior ramus S5 Filum terminale externum

Coccygeal (Co)

Posterior View

1.37

INFERIOR END OF DURAL SAC I

The posterior parts of the lum bar vertebrae and sacrum were rem oved, along with the fat and internal (epidural) venous plexus that occupy the epidural space. Note that the inferior lim it of the dural sac is at the level of the posterior superior iliac spine (body of 2nd sacral vertebra); the dura continues as the lum term inale externum .

Ep id ural an e st h e sia (b lo ck). An anesthetic can be injected into the extradural sp ace. The anesthetic has direct effect on the spinal nerve roots in the epidural space. The patient loses sensation inferior to the level of the block (see Fig. 1.38C).

SPINAL CORD AND MENINGES Spinal cord

Back

45

Dura mater Arachnoid mater

Posterior root Radicular branch of spinal vein T12 spinal nerve

Bright contrast-enhanced CSF within subarachnoid space in the lumbar cistern

Denticulate ligament

Anterior and posterior roots joining to form: L1 spinal nerve

Conus medullaris Darker “filling defects” surrounded by CSF are nerve roots of the cauda equina

Dura mater

L2 spinal nerve

Dural sleeve containing L4 nerve root

Filum terminale internum

Posterior root Anterior root L3 spinal nerve

Cauda equina Arachnoid mater

L4 spinal nerve

Subarachnoid space L5 pedicle Pedicle of L5 vertebra

L5 spinal nerve (in dural sleeve)

Superior articular process of sacrum

A. Posterior View B. Frontal Myelogram Conus medullaris Interspinous ligament

L2

Epidural space

CSF in lumbar cistern

Lumbar spinal puncture for spinal anesthesia

Filum terminale internum Spinous process of L4

Lumbar injection for epidural anesthesia S2 Sacrum

Spinal dural sac Epidural space in sacral canal

Filum terminale externum

C. Sagittal Section

INFERIOR END OF DURAL SAC II

1.38

A. Inferior dural sac and lum bar cistern of subarachnoid space (opened). B. Myelogram of the lum bar region of the vertebral colum n. Contrast m edium was injected into the subarachnoid space. C. Lum bar spinal puncture and epidural anesthesia. • The conus m edullaris continues as a glistening thread, the lum term inale internum , which descends with the nerve roots, constituting the cauda equina. • In the adult, the spinal cord usually ends at the level of the disc between vertebrae L1 and L2. Variations: 95% of cords end within the lim its of the b odies of L1 and L2, whereas 3% end posterior to the inferior half of T12, and 2% posterior to L3. To obtain a sam p le o f CSF fro m t h e lum b ar cist e rn , a lum bar puncture needle, tted with a stylet, is inserted into the subarachnoid space. Flexion of the vertebral colum n facilitates insertion of the needle by stretching the ligam enta ava and spreading the lam inae and sp inous processes apart. The needle is inserted in the m idline between the spinous processes of the L3 and L4 (or the L4 and L5) verteb rae. At these levels in adults, there is little danger of dam aging the spinal cord.

46

Back

SPINAL CORD AND MENINGES

Spinal cord Dural sleeve Spinal nerve

Pia mater (denticulate ligament) Dura mater

Anterior rootlets

Posterior ramus Arachnoid mater Anterior ramus Internal vertebral venous plexus Epidural fat Hemi-azygos vein

Posterior intercostal artery Spinal nerve

Anterior longitudinal ligament

Intervertebral foramen

Aorta

Rami communicantes Thoracic duct Transverse process

Azygos vein

Posterior Vein intercostal Artery Intercostal nerve White ramus communicans Gray ramus communicans Sympathetic trunk Right Anterolateral View

1.39

SPINAL CORD AND PREVERTEBRAL STRUCTURES

The vertebrae have been rem oved superiorly to expose the sp inal cord and m eninges. • The aorta descends to the left of the m idline, with the thoracic duct and azygos vein to its right. • Typically, the azygos vein is on the right side of the vertebral bodies, and the hem i-azygos vein is on the left.

• The thoracic sym pathetic trunk and ganglia lie lateral to the thoracic vertebrae; the ram i com m unicantes connect the sym pathetic ganglia with the spinal nerve. • A sleeve of dura m ater surrounds the spinal nerves and blends with the sheath (epineurium ) of the spinal nerve. • The dura m ater is separated from the walls of the vertebral canal by epidural fat and the internal vertebral venous plexus.

Back

SPINAL CORD AND MENINGES

47

Central canal Posterior funiculus (PF) Posterior horn of gray matter Lateral funiculus (LF)

Posterior

Anterior horn of gray matter

Dura Arachnoid Mater Pia Cervical nerves

Anterior funiculus (AF)

Anterior

Anterior median fissure

Cervical cord

Dural sleeve

Dura Mater Arachnoid

PF LF

Posterior rootlets Spinal ganglion

Posterior horn

Lateral horn

AF

Anterior horn

Thoracic cord Thoracic nerves

Subarachnoid space Denticulate ligament

Posterior horn PF LF Anterior horn AF Lumbar cord Posterior horn

Cauda equina

Anterior horn

Lumbar nerves Sacral cord

B. Transverse Sections through the Spinal Cord

Sacral and coccygeal nerves

A. Posterior View

ISOLATED SPINAL CORD AND SPINAL NERVE ROOTS WITH COVERINGS AND REGIONAL SECTIONS

1.40

A. The spinal dural sac has been op ened to reveal arachnoid and p ia m ater as well as spinal cord and p osterior nerve roots. B. Cervical, thoracic, lum bar, and sacral spinal cord.

Back

48

SPINAL CORD AND MENINGES

Basilar artery Anterior inferior cerebellar artery Posterior inferior cerebellar artery

Vertebral artery

Posterior inferior cerebellar artery Vertebral artery

Anterior spinal artery

Posterior spinal arteries

Anterior segmental medullary arteries

Cervical vertebrae

Posterior segmental medullary arteries

Ascending cervical artery

Ascending cervical artery

Deep cervical artery

Deep cervical artery Vertebral artery

Vertebral artery Right subclavian artery

Right subclavian artery

Anterior segmental medullary artery Spinal branch

Posterior radicular arteries (purple)

Dorsal branch

Spinal branch

Posterior intercostal artery Descending aorta

Posterior intercostal arteries

Thoracic vertebrae

Anterior radicular arteries (purple)

Posterior segmental medullary artery

Posterior intercostal artery Anterior segmental medullary artery

Dorsal branch

Dorsal branch

Posterior intercostal artery

Spinal branch

Spinal branch Posterior intercostal artery Great anterior segmental medullary artery (of Adamkiewicz)

Posterior segmental medullary artery Conus medullaris

Anterior segmental medullary artery

Dorsal branch Spinal branch

Dorsal branch

Lumbar artery

Spinal branch Lumbar vertebrae

Lumbar artery

Filum terminale

Cauda equina Median sacral artery Internal iliac artery Lateral sacral artery

Lateral sacral artery

Spinal branch

A.

1.41

Sacral vertebrae

Anterior View

Spinal branches

Posterior View

BLOOD SUPPLY OF SPINAL CORD

A. Arteries of sp in al cord . The seg m ental reinforcem ents of b lood sup p ly from the seg m ental m ed ullary arteries are im p ortant in sup p lying b lood to the anterior and p osterior sp inal arteries.

Fractures, dislocations, and fracture-d islocations m ay interfere with the b lood sup p ly to the sp inal cord from the sp in al and m ed ullary arteries.

SPINAL CORD AND MENINGES

Back

49

POSTERIOR Posterior spinal artery

Posterior spinal veins

Posterior radicular artery

Posterior internal vertebral venous plexus

Pial arterial plexus

Pial venous plexus

Spinal nerve

Spinal nerve

Intervertebral vein

Spinal branch

Anterior internal vertebral venous plexus

Anterior segmental medullary artery

Anterior spinal veins

Anterior spinal artery

Basivertebral vein

B. Transverse Section ANTERIOR

Sulcal artery in anterior median fissure

Posterior radicular artery

Spinal ganglion Spinal branch*

Anterior spinal artery

Anterior segmental medullary artery Posterior radicular artery Spinal nerve Anterior radicular artery Posterior segmental medullary artery

* Spinal branches arise from the vertebral, intercostal, lumbar, or sacral artery, depending on level of spinal cord.

C. Anterolateral View

BLOOD SUPPLY OF SPINAL CORD (continued )

1.41

B. Arterial supp ly and venous drainage. C. Segm ental m edullary and radicular arteries. • The spinal arteries run longitudinally from the brainstem to the conus m edullaris of the spinal cord. By them selves, the anterior and posterior spinal arteries supply only the short superior part of the spinal cord. • The anterior and posterior segm ental m edullary arteries enter the IV foram en to unite with the spinal arteries to supply blood to the spinal cord. The great anterior segm ental m edullary artery (Adam kiewicz artery) occurs on the left side in 65% of people. It reinforces the circulation to two thirds of the spinal cord. • Posterior and anterior roots of the spinal nerves and their coverings are supp lied by posterior and anterior radicular arteries, which run along the nerve roots. These vessels do not reach the posterior or anterior spinal arteries. • The anterior and posterior spinal veins are arranged longitudinally; they com m unicate freely with each other and are drained by anterior and posterior m edullary and radicular veins. The veins draining the spinal cord join the internal vertebral plexus in the epidural space. Isch e m ia. De ciency of blood supp ly (ischem ia) of the spinal cord can lead to m uscle weakness and p aralysis. The sp inal cord m ay also suffer circulatory im pairm ent if the segm ental m edullary arteries, particularly the great anterior segm ental m edullary artery (of Adam kiewicz), are narrowed by obstructive arterial disease or aortic clam ping during surgery.

50

Back

VERTEBRAL VENOUS PLEXUSES

Basivertebral vein

Anterior internal vertebral venous plexus

Posterior external vertebral venous plexus

Anterior external vertebral venous plexus

Spinous process Vertebral body Intervertebral disc Posterior internal vertebral venous plexus

A. Median Section

1.42

VERTEBRAL VENOUS PLEXUSES

A. Median section of lum bar spine. B. Superior view of lum bar vertebra with the vertebral body sectioned transversely. • There are internal and external vertebral venous plexuses, com m unicating with each other and with both system ic veins and the portal system . In fe ct io n an d t um o rs can sp re ad from the areas drained by the system ic and portal veins to the vertebral venous system and lodge in the vertebrae, spinal cord, brain, or skull. • The internal vertebral venous p lexus, located in the vertebral canal, consists of a plexus of thin-walled, valveless veins that surround the dura m ater. Cranially, the internal venous plexus com m unicates through the foram en m agnum with the occipital and basilar sinuses; at each spinal segm ent, the plexus receives veins from the sp inal cord and a basivertebral vein from the vertebral body. The plexus is drained by IV veins that pass through the intervertebral and sacral foram ina to the vertebral, intercostal, lum bar, and lateral sacral veins. • The anterior external vertebral venous plexus is form ed by veins that course through the body of each vertebra. Veins that pass through the ligam enta ava form the posterior external vertebral venous p lexus. In the cervical region, these plexuses com m unicate with the occipital and deep cervical veins. In the thoracic, lum bar, and pelvic regions, the azygos (or hem i-azygos), ascending lum bar, and lateral sacral veins, respectively, further link segm ent to segm ent.

Posterior external vertebral venous plexus Posterior internal vertebral venous plexus Anterior internal vertebral venous plexus Intervertebral vein

Lumbar vein Ascending lumbar vein

Basivertebral vein Vertebral body

B. Superior View

Anterior external vertebral venous plexus

COMPONENTS OF SPINAL NERVES

Back

51

Posterior root and rootlets

Nerves carrying somatic and sympathetic nerve fibers to the body wall and limbs: All dorsal rami and: Cervical plexus (C1–C4)

Sympathetic trunk

Brachial plexus (C5–T1)

Spinal nerve C7

Posterior ramus

T1

Gray ramus communicans

Anterior root and rootlets

Sympathetic ganglion

Anterior ramus

White ramus communicans

B. Parts of spinal nerves

Intercostal nerves (T1–T11) and subcostal nerve (T12)

T12 L1

C. Somatic sensory (green) and motor (blue) fibers

Presynaptic sympathetic neuron in lateral horn

Lumbar plexus (L1–L4) L5 S1

Sacral plexus (L4–S4)

Coccygeal plexus (S4–Co)

D. Sympathetic fibers at T1–L2(3) spinal levels Co

A. Anterior View

OVERVIEW OF THE INNERVATION OF THE LIMBS AND BODY WALL

1.43

A. Overview. B. Parts of spinal nerve. C. Som atic sensory and m otor bers. D. Sym pathetic bers at T1–L2 levels. E. Parasym pathetic bers at S1–S4 levels coursing with pudendal nerve.

Pelvic splanchnic nerve

E. Parasympathetic fibers at S2–4 spinal cord levels B–E. Anterolateral Views

52

Back

COMPONENTS OF SPINAL NERVES

Spinal nerves:

Spinal Vertebral nerves: body: C1 C1

Regions of spinal cord: Cervical

C1

Regions of spinal cord:

C4

C3 C5 C6 C7 C8 T1 T1 T2 T3

Cervical

C2

C6 C7 C8 T1 T1

Thoracic

T4 T5 T6

T2 T3 T4

Regions of spinal cord/spinal nerves:

T5 T6 T7 T8

T7

Cervical

Sacral

T8

Thoracic

Coccygeal

T9

Lumbar

T9 T10

T10 T11 Lumbar

T12

T11

L1

Sacral

T12

L1

L1 Coccygeal

L1 L2

L2

Cauda equina

L3

L3

Filum terminale internum L4

L4 L5

S1 S1

Sacral

S2

L5 S5 Co1

Filum terminale externum

A. Sagittal Section

S2 S4 S5

Coccygeal

1.44

C2

C4

C5

Thoracic

C1

C2

C2 C3

Lumbar

Vertebral body:

S1

S1

S3

Co1

B. Sagittal Section

SPINAL CORD AND SPINAL NERVES

A. Sp inal cord at 12 weeks gestation. B. Spinal cord of an adult. • Early in developm ent, the sp inal cord and vertebral (sp inal) canal are nearly eq ual in length. The canal grows longer, so sp inal nerves have an increasingly longer course to reach the IV foram en at the correct level for their exit. The spinal cord of adults term inates between vertebral bodies L1–L2. The rem aining

sp inal nerves, seeking their IV foram en of exit, form the cauda eq uina. • All 31 pairs of sp inal nerves—8 cervical (C), 12 thoracic (T), 5 lum bar (L), 5 sacral (S), and 1 coccygeal (Co)—arise from the sp inal cord and exit through the IV foram ina in the vertebral colum n.

Back

COMPONENTS OF SPINAL NERVES

53

Spinal nerves: C1 Anterior ramus

Anterior ramus Posterior ramus (cut end)

C5 T1

Peripheral nerves: Axillary nerve

Peripheral nerves: Musculocutaneous nerve

Radial nerve

Median nerve

Ulnar nerve

Radial nerve T12 L1

Ulnar nerve

Superficial branch of radial nerve

Deep branch of radial nerve

Posterior interosseous nerve L5 S1

Ulnar nerve

Superficial branch of radial nerve

S5 Co

Ulnar nerve

Obturator nerve

Median nerve

Femoral nerve

Sciatic nerve Saphenous nerve

Common fibular (peroneal) nerve Common fibular (peroneal) nerve Tibial nerve

Superficial fibular (peroneal) nerve

Superficial fibular (peroneal) nerve Deep fibular (peroneal) nerve

Deep fibular (peroneal) nerve

Lateral plantar nerve Medial plantar nerve

C. Posterior View

SPINAL CORD AND SPINAL NERVES (continued ) C. and D. Perip heral nerves. • The anterior ram i sup ply nerve bers to the anterior and lateral regions of the trunk and upp er and lower lim bs.

D. Anterior View

1.44 • The posterior ram i supply nerve bers to synovial joints of the vertebral colum n, deep m uscles of the back, and overlying skin.

Back

54

DERMATOMES AND MYOTOMES

C2

C2

C3

C6

C4 C5

C4

C4

T2 T3

T2

T2 T1 C6 C8 C7

T11

C6

T1

T12

L1

L1 C8

C6

S3

C6 C7

L3

C7 C8

S3

L2

T2

T1

C6

L3 S3

S4

S3

L2

C5

L4

S3

C4

T2

T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 L1 L2

T2

T6 T7 T8 T9 T10

T1

T2

C5

T5

C6

C4

C5

T4 T2

C3

C5

Co S5

S3

C6 C8 C7

L2 S4 S2

S2

S2

S2

L3 L3

L3

L5

S2

L5

S1 S2

L4

L5

L4

S2

S1 L5

S2 L4

L4 L5

L5 S1 S1

L5

Inferior View

L5

Anterolateral View

S1

A.

L5

S1

Posterior View

Skeletal muscle: Skin: myotome dermatome

1.45

DERMATOMES

A. Derm atom e m ap. From clinical studies of lesions in the posterior roots or spinal nerves, derm atom e m aps have been devised that indicate the typical patterns of innervation of the skin by speci c spinal nerves. (Based on Foerster O. The derm atom es in m an. Brain. 1933;56:1.) B. Schem atic illustration of a derm atom e and m yotom e. The unilateral area of skin innervated by the general sensory bers of a single spinal nerve is called a derm atom e.

Spinal nerve

Anterior (motor) root

B.

Posterior (sensory) root

Back

DERMATOMES AND MYOTOMES

55

Flexion (elbow)

C5, C6 Lateral rotation (shoulder) C5

Extension (elbow)

Medial rotation (shoulder) C6, C7, C8

C6, C7 Abduction (shoulder)

Finger flexion C7, C8

C6, C7

C5

Adduction (shoulder)

Lateral external rotation (hip) L5, S1

Extension (wrist)

Flexion (wrist) C6, C7

B. Lateral View

C6, C7, C8

Extension (shoulder)

Medial internal rotation (hip) L4, L5 Finger extension C7, C8

C5

Flexion (shoulder)

Supination (forearm) C6 Extension (hip)

Pronation (forearm) C7, C8

C. Anterior View 40º

C6, C7, C8

Flexion (hip)

L4, L5

L2, L3

50º Flexion Flesion (knee) 0º Adduction (hip)

A. Anterior View The movements associated with each bolded segment are most commonly tested to determine the neurologic level of a lesion.

L2, L3, L4

L5, S1

Extension (knee)

Abduction (hip)

L5, S1 Abduction

Abduction T1

T1 Adduction Abduction and Adduction of Digits (Metacarpophalangeal Joints)

D. Anterior View

MYOTOMES Som atic m otor (general som atic efferent) bers transm it im pulses to skeletal (voluntary) m uscles. The unilateral m uscle m ass receiving innervation from the som atic m otor bers conveyed by a single spinal nerve is a m yotom e. Each skeletal m uscle is innervated by the

L3, L4

Dorsiflexion (ankle) L4, L5

E. Lateral View Plantarflexion (ankle)

S1, S2

1.46 som atic m otor bers of several spinal nerves; therefore, the m uscle m yotom e will consist of several segm ents. The m uscle m yotom es have been grouped by joint m ovem ent to facilitate clinical testing. The intrinsic m uscles of the hand constitute a single m yotom e—T1.

56

Back

AUTONOMIC NERVES

Ciliary ganglion

CN III

Innervation via cranial outflow

Pterygopalatine ganglion CN VII Otic ganglion Submandibular ganglion

CN IX

Lacrimal gland Nasal, palatine, and pharyngeal glands

Eye (iris, ciliary muscles)

CN X

Cranial parasympathetic outflow (via four cranial nerves)

Parotid gland Sublingual and submandibular glands Heart

Larynx Trachea Bronchi Lungs Liver Gallbladder

Stomach Pancreas

Kidney Small intestine Proximal large intestine

Left colic (splenic) flexure, dividing cranial and sacral parasympathetic supply

S2 S3 S4

Distal large intestine Rectum

Sacral parasympathetic outflow (via pelvic splanchnic nerves) Bladder Penis (or clitoris)

Parasympathetic fibers Presynaptic Postsynaptic

1.47

Innervation via sacral outflow

DISTRIBUTION OF PARASYMPATHETIC NERVE FIBERS

The presynaptic nerve cell bodies of the parasym pathetic system are located in two sites: the gray m atter of the brainstem (cranial

parasym pathetic out ow) and in the gray m atter of the sacral segm ents of the sp inal cord (sacral parasym pathetic out ow).

Back

AUTONOMIC NERVES Parietal distribution

Visceral distribution

(via gray rami communicans)

(via splanchnic nerves and peri-arterial plexuses)

57

Medulla

Blood vessels, sweat glands, and arrector muscles of hairs of skin Eyeball (iris) and blood vessels of visceral structures

Cephalic arterial ramus

C1 C2

Carotid peri-arterial plexus

C3 C4

Cardiopulmonary splanchnic nerves

C5 C6

Gray rami via anterior rami of all parts of spinal nerves for distribution to body walls and limbs (vasomotion, sudomotion, and pilomotion)

WRC

C7 C8

Heart WRC

T1

Larynx Trachea Bronchi Lungs

T2 T3 T4 T5

Abdominopelvic splanchnic nerves

T6 T7 T8 T9

Liver Gallbladder

Diaphragm

1 2

T10

Celiac ganglion Stomach Pancreas Spleen

T11 T12

3

L1

4

L2

Aorticorenal ganglion

L3 L4 L5

Superior mesenteric ganglion

Large intestine Small intestine Kidney Suprarenal (adrenal) gland Rectum Internal anal sphincter

S1 S2 S3 S4

Inferior mesenteric ganglion

S5

Bladder Penis (or clitoris) Gonad

Sympathetic fibers Presynaptic Postsynaptic WRC White rami communicantes

1 = Greater splanchnic nerve 2 = Lesser splanchnic nerve 3 = Least splanchnic nerve 4 = Lumbar splanchnic nerves

DISTRIBUTION OF SYMPATHETIC NERVE FIBERS The cell bodies of p resynaptic neurons of the sym p athetic system are located in the interm ediolateral cell colum n and extend

1.48 between the rst thoracic and the second lum bar segm ents of the sp inal cord.

58

Back

AUTONOMIC NERVES

V fibers Visceral isceral fibers Visceral afferent Presynaptic sympathetic Postsynaptic sympathetic Presynaptic parasympathetic Postsynaptic parasympathetic

Spinal ganglion

Visceral parasympathetic pathway (via Vagus nerve—CN X)

Spinal nerve Posterior ramus

Anterior ramus Visceral afferent (reflex) fiber

Gray ramus communicans Sympathetic ganglion Splanchnic nerve White ramus communicans

Parasympathetic ganglion

Visceral sympathetic pathway (via cardiopulmonary splanchnic nerve) Visceral afferent (pain) fiber

A.

1.49

VISCERAL AFFERENT AND VISCERAL EFFERENT (MOTOR) INNERVATION

A. Schem atic illustration. Visceral afferent b ers have im p ortant relationship s to the central nervous system (CNS), b oth anatom ically and functionally. We are usually un aware of the sensory inp ut of these b ers, which p rovid es inform ation ab out the cond ition of the b od y’s internal environm ent. This inform ation is integ rated in the CNS, often trig g ering visceral or som atic re exes or b oth. Visceral re exes reg ulate b lood p ressure and chem istry b y altering such functions as heart and resp iratory rates and vascular resistance. Visceral sensation th at reaches a conscious level is g enerally categ orized as p ain that is usually p oorly localized and m ay b e p erceived as hung er or nausea. However, ad eq uate stim ulation m ay elicit true p ain. Most visceral/ re ex (unconscious) sensation and som e p ain travel in visceral afferent b ers that accom p any the p arasym p athetic b ers retrog rad e. Most visceral p ain im p ulses (from the heart and m ost org ans of the p eritoneal cavity) travel along visceral afferent b ers accom p anyin g sym p athetic b ers.

Visceral efferen t (m ot or) in n ervat io n . The efferent nerve bers and ganglia of the ANS are organized into two system s or divisions. 1. Sym p at h e t ic (t h o raco lum b ar) d ivisio n . In general, the effects of sym pathetic stim ulation are catabolic (p reparing the body for “ ight or ght”). 2. Parasym p at h e t ic (cran io sacral) d ivisio n . In general, the effects of parasym p athetic stim ulation are anabolic (prom oting norm al function and conserving energ y). Conduction of im p ulses from the CNS to the effector organ involves a series of two neurons in both sym pathetic and parasym pathetic system s. The cell body of the presynaptic (preganglionic) neuron ( rst neuron) is located in the gray m atter of the CNS. Its ber (axon) synapses on the cell body of a postsynaptic (postganglionic) neuron, the second neuron in the series. The cell bodies of such second neurons are located in autonom ic ganglia outside the CNS, and the postsynap tic bers term inate on the effector organ (sm ooth m uscle, m odi ed cardiac m uscle, or glands).

AUTONOMIC NERVES

Head (e.g., dilator muscle of iris) via cephalic arterial branch and peri-arterial plexus

Cephalic arterial branch (to head)

T1

White ramus communicans 1 Posterior ramus T3

2. Synapse at level of exit. Postsynaptic fibers are distributed by: • Thoracic cardiopulmonary splanchnic nerves • Spinal nerves to middle trunk

2

Cardiopulmonary splanchnic nerve Viscera of thoracic cavity (e.g., heart) via cardiopulmonary splanchnic nerves

Presynaptic Postsynaptic

1. Ascend and then synapse. Postsynaptic fibers are for: • Innervation of the head • Cervical cardiopulmonary splanchnic nerves • Spinal nerves to neck, upper trunk, and upper limb

T2

Anterior ramus

Sympathetic nerve fibers

Courses taken by presynaptic sympathetic fibers within the sympathetic trunks:

Gray ramus communicans

Body wall via branches of spinal nerves (vasomotion, sudomotion, and pilomotion)

59

Intermediolateral cell column (IML, lateral horn)

Superior cervical ganglion

Carotid arteries with peri-arterial plexus

Back

T4 3

3. Descend and then synapse. Postsynaptic fibers are distributed by: • Spinal nerves to lower trunk and lower limb T5

4. Pass through sympathetic trunk without synapsing to enter abdominopelvic splanchnic nerve for: • Innervation of abdominopelvic viscera

Sympathetic trunk with paravertebral ganglia 4 L4 Abdominopelvic splanchnic nerve

Lower limb via branches of spinal nerves (vasomotion, sudomotion, and pilomotion)

B. Anterolateral View

Prevertebral ganglion

Viscera of abdominopelvic cavity (e.g., stomach and intestines) via abdominopelvic splanchnic nerves

3

VISCERAL AFFERENT AND VISCERAL EFFERENT (MOTOR) INNERVATION (continued ) B. Courses taken by sym pathetic m otor bers. Presynaptic bers all follow the sam e course until they reach the sym pathetic trunks. In the sym pathetic trunks, they follow one of four possible courses. Fibers involved in providing sym pathetic innervation to the body wall and lim bs or viscera above the level of the diaphragm follow

1.49

paths 1 to 3. They synapse in the paravertebral ganglia of the sym pathetic trunks. Fibers involved in innervating abdom inopelvic viscera follow path 4 to prevertebral ganglion via abdom inopelvic splanchnic nerves. Postsynaptic bers usually do not ascend or descend within the sym pathetic trunks, exiting at the level of synapse.

Back

60

40

IMAGING OF VERTEBRAL COLUMN

40

1 9

4 10

14 16

27

13 31

2

3 17 11

19

22

15 25 23

5

6 7

20

9

8 18 12 21

4 13

5 18

19

20

30

24

25

3

6

7

12

16

17

15 25

28

26

8

31

14

27

24

2

10

26 28

28 29

29 29

A. Inferior View

B. Transverse CT Image

Key 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

Site of retropharyngeal space Longus colli Longus capitis Parotid gland Retromandibular vein Stylopharyngeus Styloglossus Stylohyoid muscle and ligament/process Internal carotid artery Internal jugular vein Rectus capitis lateralis Posterior belly of digastric Anterior arch of atlas (C1 vertebra) Lateral mass of atlas (C1) Posterior arch of atlas (C1) Vertebral artery Transverse ligament of atlas (C1) Transverse process of atlas (C1) Spinal cord Rectus capitis posterior major Obliquus capitis inferior Obliquus capitis superior Spinous process of atlas (C1) Longissimus capitis Rectus capitis posterior minor Semispinalis capitis Sternocleidomastoid Splenius capitis Trapezius Fatty mass Dens of axis (C2 vertebra) Anterior tubercle of atlas (C1) Inferior articular facet of atlas (C1) Foramen magnum Foramen transversarium Posterior tubercle of atlas (C1) Mastoid process Occipital bone of skull External occipital protuberance Ramus of mandible

32

13

13

37 35

ANTERIOR

33

33

RIGHT

34

LEFT 15

36

15

POSTERIOR

38

38

39

C. Reconstructed CT Image

1.50

IMAGING OF SUPERIOR NUCHAL REGION AT LEVEL OF ATLAS

A. Transverse section of specim en. B. Transverse CT im age. C. Three-dim ensional CT im age of the base of the skull and atlas.

Back

IMAGING OF VERTEBRAL COLUMN

61

1 1

2 2

ANTERIOR 7

8

5 4 3

3 4 5 18

18

14

15

6 19 17

11 16 9

LEFT

RIGHT

6

19

3

4 6

POSTERIOR

18

14

5 19

15

17 12 16 11 13 10 9

12 10

7

8

13

B. Transverse CT Image

A. Inferior View Key 1 2 3 4 5

Linea alba Rectus abdominis External oblique Internal oblique Transversus abdominis

6 7 8 9 10

Latissimus dorsi Descending aorta Inferior vena cava Spinalis Longissimus

11 12 13 14 15

Multifidus Rotatores Iliocostalis 4th lumbar vertebra Transverse process

16 17 18 19

Spinous process Cauda equina Psoas major Quadratus lumborum

1.51

IMAGING OF LUMBAR SPINE AT L4 A. Transverse section of specim en. B. Transverse CT im age.

1 2 3

3 4

15

4

4

6 8

16

17

15

6

5 7

12 13 14

4

10

7

8

LEFT

RIGHT

4

4

15

16

9

2 3

ANTERIOR

2

1

POSTERIOR

7

16

11

9

11

10

17 17

14

A. Inferior View

12 13

B. Transverse CT Image Key 1 2 3 4 5

Rectus abdominis External oblique Internal oblique Iliopsoas Internal iliac artery

6 7 8 9

Internal iliac vein Anterior rami Superior gluteal vessels Body of ilium

IMAGING OF SACRO-ILIAC JOINT A. Transverse section of specim en. B. Transverse CT im age.

10 11 12 13

2nd sacral vertebra Sacro-iliac joint Sacral nerve root Multifidus

14 15 16 17

Erector spinae Gluteus minimus Gluteus medius Gluteus maximus

1.52

62

Back

IMAGING OF VERTEBRAL COLUMN

Medulla oblongata

Dens C1

C1

Mastoid process

C2

Mastoid process

Cerebrospinal fluid in subarachnoid space

C2 C3 C3

C4

Vertebral artery

C5

C4

C6

C5

C7

C6

T1

Right lung

Left lung

B. Coronal MRI

A. Coronal MRI

Left lung

Right lung

Left lung

Intervertebral disc

Spinal nerve Cerebrospinal fluid

Vertebral body

Stomach

Liver

Posterior ramus

Spleen

Right crus

Anterior ramus

Suprarenal gland

Spinal cord

Left kidney

Right kidney

Splenic flexure

Small intestine

C. Coronal MRI

Left kidney

Right kidney

Psoas

D. Coronal MRI

1.53

Spinal cord

CORONAL MRIs OF CERVICAL AND THORACIC SPINE

A. and B. Cervical sp ine. C. and D. Thoracic spine.

CHAPTER 2

Up p e r Lim b System ic Overview of Upper Lim b .......................................64 Bones ..............................................................................64 Nerves .............................................................................72 Arteries ............................................................................76 Veins and Lym phatics ......................................................78 Musculofascial Com partm ents .........................................82 Pectoral Region ....................................................................84 Axilla, Axillary Vessels, and Brachial Plexus ...........................91 Scapular Region and Super cial Back .................................102 Arm and Rotator Cuff ........................................................106 Joints of Shoulder Region ...................................................120 Elbow Region .....................................................................128 Elbow Joint ........................................................................134 Anterior Forearm ...............................................................140 Anterior Wrist and Palm of Hand ........................................148 Posterior Forearm ..............................................................164 Posterior Wrist and Dorsum of Hand ..................................167 Lateral Wrist and Hand ......................................................172 Medial Wrist and Hand ......................................................175 Bones and Joints of Wrist and Hand ...................................176 Function of Hand: Grips and Pinches .................................183 Im aging and Sectional Anatom y ........................................184

64

Up p e r Lim b

SYSTEMIC OVERVIEW OF UPPER LIMB: BONES

Clavicle

Shoulder region (scapula and proximal humerus)

Shoulder joint

Scapula

Arm

Humerus

Elbow joint

Ulna Forearm

Radius

Wrist joint Carpal bones

1 2

Metacarpal bones (1–5)

3 4

5

Hand Phalanges

A. Anterior View

Key Palpable features of upper limb bones

2.1

REGIONS, BONES, AND MAJOR JOINTS OF UPPER LIMB

Joints divide the up per lim b into four m ain regions: the shoulder, arm , forearm , and hand.

SYSTEMIC OVERVIEW OF UPPER LIMB: BONES

Up p e r Lim b

Shoulder joint

65

Shoulder region (scapula and proximal humerus)

Scapula

Arm Humerus

Elbow joint

Forearm Ulna

Radius

Wrist joint

5

4

3

1

Carpal bones

2

Metacarpal bones (1–5) Hand Phalanges

B. Posterior View

Key Palpable features of upper limb bones

REGIONS, BONES, AND MAJOR JOINTS OF UPPER LIMB (continued )

2.1

Up p e r Lim b

66

SYSTEMIC OVERVIEW OF UPPER LIMB: BONES

Clavicle LATERAL

MEDIAL

B. Clavicle, Superior View

Scapula

Coracoid process

Acromion Shaft (body) of humerus

Medial border

Radius

Inferior angle

Ulna

C. Proximal Humerus,

D. Scapula, Anterior View

Anterior View

Metacarpals

Phalanges Capitulum

A. Anterior View

2.2

Medial epicondyle Trochlea E. Distal Humerus, Anterior View

F. Proximal Radius, Anterior View

G. Proximal Ulna, Medial View

OSSIFICATION AND SITES OF EPIPHYSES OF BONES OF UPPER LIMB

A. Upper lim b bones at birth. Only the diaphyses of the long bones and scapula are ossi ed. The ep iphyses, carpal bones, coracoid process, m edial border of the scapula, and acrom ion are still cartilaginous. B–I. Sites of ep iphyses (darker orange regions). The ends of the long bones are ossi ed by the form ation of one or m ore secondary centers of ossi cation; these epiphyses develop from birth to approxim ately 20 years of age in the clavicle, hum erus, radius, ulna, m etacarpals, and phalanges. Ep ip h yse s. Without knowledge of bone growth and the appearance of bones in radiographic and other diagnostic im ages at various ages, a displaced epiphysial plate could be m istaken for a fracture, and separation of an epiphysis could be interpreted as a displaced piece of fractured bone. Knowledge of the patient’s age and the location of epiphyses can prevent these errors.

H. Distal Radius, Anterior View

I. Distal Ulna,

Anterior View

Up p e r Lim b

SYSTEMIC OVERVIEW OF UPPER LIMB: BONES

67

Distal phalanx

Middle phalanx

Proximal phalanx

4

5

3

2

1 H

C

Tq L

3

4

2

R

5 1

H

C

Tz

Metacarpal

Td

P L

S

Tq

J . Anterior View (Right Hand)

5

Capitate (C)

Hamate (H)

1

2 1

Trapezoid (Td) 1

7

Td

H

6

Tz

C S

5 12 3 Pisiform (P) 4 Triquetrum (Tq) Lunate (L)

3

4

Tq

Trapezium (Tz)

L

R

P

Scaphoid (S)

U

Numbers: approximate age of ossification of carpal bones in years

K. Anterior View

L. Anteroposterior View, Right Hand Epiphyses in radiographs appear as radiolucent lines

OSSIFICATION AND SITES OF EPIPHYSES OF BONES OF UPPER LIMB (continued ) J. Ossi cation of bones of hand. Note the phalanges have a single proxim al epiphysis and m etacarpals 2, 3, 4, and 5 have single distal epiphyses. The 1st m etacarpal behaves as a phalanx by having proxim al epiphysis. Short-lived epiphyses m ay appear at the other ends of m etacarpals 1 and/ or 2. There are individual and gender differences in sequence and tim ing of ossi cation. K. Sequence of

2.2

ossi cation of carpal bones. L. Radiographs of stages of ossi cation of wrist and hand. A 2½ -year-old child (top); the lunate is ossifying, and the distal radial epiphysis (R) is present (C, capitate; H, ham ate; L, lunate; Tq, triquetrum ). An 11-year-old child (bottom). All carpal bones are ossi ed (S, scaphoid; Td, trapezoid; Tz, trapezium ; arrowhead, pisiform ), and the distal epiphysis of the ulna (U) has ossi ed.

Up p e r Lim b

68

Acromial end

SYSTEMIC OVERVIEW OF UPPER LIMB: BONES

Acromial end of clavicle

Sternal facet (articular surface)

Clavicle

Lesser tubercle Coracoid process Superior border

Acromion of scapula Greater tubercle

Shaft

Superior angle Sternal end

Clavicle

Crest of lesser tubercle Crest of greater tubercle

Deltoid tubercle

Suprascapular notch

Scapula

Intertubercular sulcus (bicipital groove)

Medial (vertebral) border

Surgical neck

A. Superior Surface

Subscapular fossa Body of scapula Inferior angle

Acromial facet (articular surface)

Clavicle

Deltoid tuberosity

Impression for costoclavicular ligament

Deltoid tubercle

Lateral border

Shaft of humerus

Subclavian groove Trapezoid line*

Humerus

Conoid tubercle*

B. Inferior Surface

Sternal end

Lateral supra-epicondylar ridge

*Tuberosity for coracoclavicular ligament (conoid and trapezoid parts)

Medial supra-epicondylar ridge

Radial fossa Lateral epicondyle

Coronoid fossa Medial epicondyle

Capitulum Humerus

Radial fossa

Trochlea

Head of radius Neck of radius Tuberosity of radius

Coronoid process Tuberosity of ulna

Coronoid fossa Anterior oblique line Medial epicondyle

Lateral epicondyle

Ulna

Trochlea

Capitulum

Shaft of radius

Shaft of ulna

Radius

Trochlear notch

Olecranon

Radial notch Head Neck

Coronoid process

Head of ulna articulating with ulnar notch of radius

Styloid process of radius

Styloid process of ulna Carpal bones

Tuberosity of ulna Tuberosity

Supinator fossa

Anterior oblique line Radius

Ulna

1 Proximal phalanx Distal phalanx

2

3

4

5

Metacarpal bones Proximal Middle

C. Anterior View

2.3

D. Anterior View

Phalanges

Distal

FEATURES OF BONES OF UPPER LIMB

A. and B. Clavicle. C. Anterior aspect of disarticulated distal end of hum erus and p roxim al end of radius and ulna. D. Anterior aspect of articulated upp er lim b.

Up p e r Lim b

SYSTEMIC OVERVIEW OF UPPER LIMB: BONES

Superior border

Spine of scapula Acromioclavicular joint

Superior angle

Acromion

Supraspinous fossa

Supraspinous fossa Supraglenoid tubercle

Acromion

Acromial angle

Head of scapula

Coracoid process

Greater tubercle

Neck of scapula

Head of humerus

Infraspinous fossa

Surgical neck of humerus Anatomical neck of humerus

Medial (vertebral) border Lateral border

Scapula

69

Deltoid tuberosity Radial groove

Inferior angle

Spine

Infraspinous fossa

Glenoid cavity Infraglenoid tubercle

Scapula Lateral border

Shaft of humerus Humerus Inferior angle Medial supra-epicondylar ridge

Lateral supra-epicondylar ridge

F. Lateral View

Lateral epicondyle Medial epicondyle

Humerus

Head of radius

Olecranon articulating with olecranon fossa of humerus Olecranon fossa

Posterior oblique line Posterior border

Medial epicondyle

Ulna

Head of ulna

Dorsal radial tubercle

Styloid process

Head

5

4

3

2

Proximal Middle

Neck Supinator crest

1

Metacarpal bones

Proximal phalanx Distal phalanx

Trochlea

Olecranon

Styloid process of radius

Carpal bones

Phalanges

Groove for ulnar nerve

Radius

Lateral epicondyle

Tuberosity

Posterior border

Ulna

Distal

Posterior oblique line Radius

G. Posterior View E. Posterior View

FEATURES OF BONES OF UPPER LIMB (continued )

2.3

E. Posterior asp ect of articulated upp er lim b bones. F. Lateral asp ect of scapula. G. Posterior aspect of disarticulated distal end of hum erus and p roxim al ends of radius and ulna.

Up p e r Lim b

70

SYSTEMIC OVERVIEW OF UPPER LIMB: BONES

C4 C5 C6 C7

Lateral cord of brachial plexus

C5 C6

C6

C7

C7

C7 C8

C8

T1

T1 T1

T1

T2

T2 Medial cord of brachial plexus

Medial cord of brachial plexus

Coracobrachialis Musculocutaneous nerve

Anterior compartment of arm

Biceps brachii Median nerve

Brachialis Ulnar nerve

Pronator teres Pronator teres Flexor carpi radialis

Anterior compartment of forearm

Anterior interosseous nerve Flexor pollicis longus Pronator quadratus

Palmaris longus

Anterior compartment of forearm

Flexor digitorum superficialis

Flexor carpi ulnaris

Flexor digitorum profundus (medial half to digits 4, 5)

Anterior compartment of forearm

Flexor digitorum profundus (lateral half to digits 2, 3)

Recurrent branch of median nerve

Palmar interossei Deep head, flexor pollicis brevis

Thenar muscles Lumbricals to digits 2, 3

Adductor pollicis

Deep branch of ulnar nerve Palmaris brevis Hypothenar muscles Innervation of arm:

Dorsal interossei

A. Anterior View

2.4

OVERVIEW OF MOTOR INNERVATION OF UPPER LIMB

Lumbricals to digits 4, 5

B. Anterior View

Anterior compartment of arm Anterior compartment of forearm Posterior compartment of arm Posterior compartment of forearm

SYSTEMIC OVERVIEW OF UPPER LIMB: BONES

Up p e r Lim b

71

C2 C3 C4 C5 Spinal C6 nerves C7 C8

C3 C4

Levator scapulae

C5

Dorsal scapular nerve - rhomboids Suprascapular nerve

C6

Supraspinatus

C7

T1

T1

Shoulder region Infraspinatus

T2 Deltoid

Posterior cord of brachial plexus

Teres minor

Subscapularis

Axillary nerve Shoulder region

Teres major Radial nerve Latissimus dorsi Triceps brachii (lateral head)

Triceps brachii (long head)

Posterior compartment of arm

Triceps brachii (medial head) Superficial branch of radial nerve (sensory) Brachioradialis Anconeus

Deep branch of radial nerve Extensor carpi radialis longus Extensor carpi radialis brevis

Posterior compartment of forearm

Posterior interosseous nerve

Supinator

Extensor carpi ulnaris Extensor digiti minimi Extensor digitorum

Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus Extensor indicis

C. Posterior View

OVERVIEW OF MOTOR INNERVATION OF UPPER LIMB (continued )

2.4

A. Musculocutaneous and m edian nerves. The m usculocutaneous nerve innervates all the m uscles of the anterior com partm ent of the arm . The m edian nerve innervates m uscles of the anterior com partm ent of the forearm (with 1½ exceptions that are innervated by the ulnar nerve), the lum bricals to digits 2 and 3, and the intrinsic m uscles of the thum b (thenar m uscles). B. Ulnar nerve. The ulnar nerve innervates the exor carp i ulnaris and ulnar half of the exor digitorum p rofundus in the forearm , the hypothenar and interosseous m uscles of the hand, the lum bricals to digits 3 and 4, and 1½ thenar m uscles (adductor pollicis and the deep head of the exor pollicis brevis). C. Radial nerve. The radial nerve innervates all m uscles of the posterior com partm ents of the arm and forearm .

Up p e r Lim b

72

SYSTEMIC OVERVIEW OF UPPER LIMB: NERVES

Supraclavicular nerves (C3, C4)

Supraclavicular nerves (C3, C4)

Superior lateral cutaneous nerve of arm (from axillary nerve)

Intercostobrachial nerve (from 2nd/3rd intercostal nerve)

Intercostobrachial nerve

Posterior cutaneous nerve of arm (from radial nerve)

Medial cutaneous nerve of arm (from medial cord of brachial plexus) Inferior lateral cutaneous nerve of arm (from radial nerve)

Inferior lateral cutaneous nerve of arm

Medial cutaneous nerve of forearm

Posterior cutaneous nerve of forearm (from radial nerve) Lateral cutaneous nerve of forearm (from musculocutaneous nerve)

Medial cutaneous nerve, of forearm, posterior branches

Radial nerve, superficial branch

From radial nerve

Posterior cutaneous nerve of forearm

Lateral cutaneous nerve of forearm, posterior branch

Anterior branch

Dorsal (cutaneous) branch of ulnar nerve Ulnar nerve Median nerve

Palmar (cutaneous) branches of

Dorsal (cutaneous) branch of ulnar nerve

Radial nerve, superficial branch

Dorsal digital branches

Median nerve

Median nerve, palmar digital branches

Ulnar nerve, superficial branch

A. Anterior View

2.5

Posterior cutaneous nerve of forearm

Posterior branch Medial cutaneous nerve of forearm (from medial cord of brachial plexus)

Lateral cutaneous nerve of forearm Posterior branch (from musculoAnterior branch cutaneous nerve)

Superior lateral cutaneous nerve of arm (from axillary nerve)

B. Posterior View

CUTANEOUS NERVES OF UPPER LIMB

Sum m ary of distribution of the peripheral (nam ed) cutaneous nerves in upper lim b. Most nerves are branches of nerve plexuses and therefore contain bers from m ore than one sp inal nerve.

SYSTEMIC OVERVIEW OF UPPER LIMB: NERVES

TABLE 2.1

Up p e r Lim b

73

CUTANEOUS NERVES OF UPPER LIMB

Nerve Supraclavicular nerves Superior lateral cutaneous nerve of arm Inferior lateral cutaneous nerve of arm Posterior cutaneous nerve of arm Posterior cutaneous nerve of forearm

Spina l Nerve Components

Source

Course/Distribution

C3–C4

Cervical plexus

Pass anterior to clavicle, immediately deep to platysma, and supply the skin over the clavicle and superolateral aspect of the pectoralis major muscle

Axillary nerve (posterior cord of brachial plexus)

Emerges from posterior margin of deltoid to supply skin over lower part of this muscle and the lateral side of the midarm

C5–C6

Arises with the posterior cutaneous nerve of forearm; pierces lateral head of triceps brachii to supply skin over the inferolateral aspect of the arm Arises in axilla and supplies skin on posterior surface of the arm to olecranon

C5–C8

Radial nerve (posterior cord of brachial plexus)

Super cial branch of radial nerve

Arises with the inferior lateral cutaneous nerve of the arm; pierces lateral head of triceps brachii to supply skin over the posterior aspect of the arm Arises in cubital fossa; supplies lateral (radial) half of the dorsal aspect of hand and thumb, and proximal portion of the dorsal aspects of digits 2 and 3, and the lateral (radial) half of dorsal aspect of digit 4

Lateral cutaneous nerve of forearm

C6–C7

Musculocutaneous nerve (lateral cord of brachial plexus)

Arises between biceps brachii and brachialis muscle as continuation of musculocutaneous nerve distal to branch to brachialis; emerges in cubital fossa lateral to biceps tendon and median cubital vein; supplies skin along radial (lateral) border of forearm to base of thenar eminence

Median nerve

C6–C7 (via lateral root); C8–T1 (via medial root)

Lateral and medial cords of brachial plexus

Courses with brachial artery in arm and deep to exor digitorum super cialis in forearm; distal to origin of palmar cutaneous branch, traverses carpal tunnel to supply skin of palmar aspect of radial 3½ digits and adjacent palm, plus distal dorsal aspects of same, including nail beds

Ulnar nerve

(C7), C8–T1

Medial cutaneous nerve of forearm

C8–T1

Medial cutaneous nerve of arm

C8–T2

Intercostobrachial nerve

T2

Courses with brachial, superior ulnar collateral, and ulnar arteries; supplies skin of palmar and dorsal aspects of medial (ulnar) 1½ digits and palm and dorsum of hand proximal to those digits Medial cord of brachial plexus

Pierces deep fascia with basilic vein in midarm; divides into anterior and posterior branches supplying skin over anterior and medial surfaces of forearm to wrist Smallest and most medial branch of brachial plexus; communicates with intercostobrachial nerve and then descends medial to brachial artery and basilic vein to innervate skin of distal medial arm

Lateral cutaneous branch of 2nd intercostal nerve

Arises distal to angle of 2nd rib; supplies skin of axilla and proximal medial arm

Up p e r Lim b

74

SYSTEMIC OVERVIEW OF UPPER LIMB: NERVES

Glenohumeral (shoulder) joint

Elbow joint

Glenohumeral (shoulder) joint

Extension C6, C7

Medial rotation C6, C7, C8

Lateral rotation C5

Flexion C5, C6

Adduction C6, C7, C8 Anterior View

Extension C6, C7, Abduction C8 C5

Flexion C5

Wrist joint Flexion C6, C7

Extension C6, C7

Lateral View Movements at elbow and wrist joints Lateral View Movements at glenohumeral joint

Superior radio-ulnar joint Inferior radio-ulnar joint Supination C6 Pronation C7, C8

Anterior View

Movements at radio-ulnar joints

2.6

MCP joints Digital flexion C7, C8 Digital extension C7, C8

IP joints

Anterior Views

Lateral abduction

Movements at metacarpophalangeal and interphalangeal (IP) joints

T1

Medial abduction

Abduction of 3rd digit

Abduction T1 Adduction

T1 Abduction and Adduction of digits 2–5

Movements at metacarpophalangeal (MCP) joints

MYOTOMES AND MYOTATIC (DEEP TENDON STRETCH) REFLEXES

Myo t o m e s. Som atic m otor (g eneral som atic efferent) b ers transm it im p ulses to skeletal (voluntary) m uscles. Th e unilateral m uscle m ass receivin g in form ation from th e som atic m otor b ers con veyed b y a sin g le sp in al n erve is a m yotom e. Th e m ovem en ts associated with each b old ed seg m en t in Tab le 2.2 are m ost com m on ly tested to d eterm in e th e n eurolog ic level

TABLE 2.2

of a lesion . Myo t at ic re e xe s. A m yotatic re ex (d eep ten d on or stretch re ex) is an involuntary contraction of a m uscle in resp onse to sud d en stretchin g . Myotatic re exes are elicited b y b riskly tap p in g th e ten d on with a re ex h am m er. Each ten d on re ex is m ed iated b y sp eci c sp in al nerves. Stretch re exes con trol m uscle ton e.

CLINICAL MANIFESTATIONS OF NERVE ROOT COMPRESSION: UPPER LIMB

Hernia ted Disc Between

Compressed Nerve Root

Derma tome Affected

Muscles Affected

Movement Wea kness

Nerve a nd Myota tic Re ex Involved

C4 and C5

C5

C5 Shoulder Lateral surface UL

Deltoid

Abduction of shoulder

Axillary nerve ↓ Biceps jerk

C5 and C6

C6

C6 Thumb

Biceps Brachialis Brachioradialis

Flexion of elbow Supination/pronation of forearm

Musculocutaneous nerve ↓ Biceps jerk ↓ Brachioradialis jerk

C6 and C7

C7

C7 Posterior surface UL Middle and index ngers

Triceps Wrist extensors

Extension of elbow Extension of wrist

↓ Triceps re ex

UL, upper limb.

Up p e r Lim b

SYSTEMIC OVERVIEW OF UPPER LIMB: NERVES

75

Key Pre-axial (C3–C7)

Postaxial (C8–T4)

C4

C5

C6 C6

T2

T1

C8

T2

T1

C8

A.

T3

T3 T4

Anterior View C3 C3 C4

C3

C5

C7

C7

C3

C4

T4

C4 C5 T2

C6

C5

C6

T3 T3 T4

T4

B.

C7 C8

T1 T2

T1

C8

Posterior View C4

C5 C6

C5

C6 C7

T1

C7 C8

T1

C8

C.

C7

C4 C4 C5

Anterior View

C4

C3

T2 T3 T4

T2 T3 T4

C5 C6 C7

C6 C6

C8

D.

C3

T1 T2 T3 T4

C7 T1 T2 T3 T4

C8

C7

C8 Posterior View

2.7

DERMATOMES OF UPPER LIMB Two different derm atom e m aps are com m only used. A. and B. The derm atom e pattern according to Foerster (1933) is preferred by m any because of its correlation with clinical ndings. In the Foerster schem a, d erm atom es C6–T1 are d isp laced from the trunk

TABLE 2.3

a

to lim b s. C. and D. The derm atom e p attern according to Keegan and Garrett (1948) is p referred b y others for its correlation with develop m ent. Althoug h d ep icted as d istinct zones, adjacent d erm atom es overlap considerably except along the axial line.

DERMATOMES OF UPPER LIMB

Spina l Segment/Nerve(s)

Description of Derma tome(s)

C3, C4

Region at base of neck extending laterally over shoulder

C5

Lateral aspect of arm (i.e., superior aspect of abducted arm)

C6

Lateral forearm and thumb

C7

Middle and ring ngers (or middle three ngers) and center of posterior aspect of forearm

C8

Little nger, medial side of hand and forearm (i.e., inferior aspect of abducted arm)

T1

Medial aspect of forearm and inferior arm

T2

Medial aspect of superior arm and skin of axilla a

Not indicated on the Keegan and Garrett map. However, pain experienced during a heart attack, considered to be mediated by T1 and T2, is commonly described as “radiating down the medial side of the left arm.”

76

Up p e r Lim b

SYSTEMIC OVERVIEW OF UPPER LIMB: ARTERIES

Cervicodorsal Right trunk* subclavian Suprascapular artery artery Axillary artery (begins lateral to border 1st rib)

Inferior thyroid artery Thyrocervical trunk Vertebral artery Right and left common carotid arteries

Thoraco-acromial artery

Left subclavian artery

Quadrangular space

Brachiocephalic trunk Circumflex humeral artery

Posterior

Arch of aorta

Anterior

Internal thoracic artery Superior thoracic artery (branch of axillary artery)

Subscapular artery Circumflex scapular artery Brachial artery (begins at inferior border of teres major muscle Deltoid (ascending) branch Thoracodorsal artery

Lateral thoracic artery

Profunda brachii artery (deep artery of arm) Radial collateral artery Medial collateral artery

Superior and inferior ulnar collateral arteries

Radial recurrent artery

Brachial artery Anterior and posterior ulnar recurrent arteries

Radial artery Recurrent interosseous artery Posterior interosseous artery

Radial artery

Ulnar artery Common interosseous artery Anterior interosseous artery Ulnar artery

Palmar carpal arch Deep palmar arch

Palmar carpal branch of ulnar artery Superficial palmar arch

A. Palmar View

2.8

ARTERIES AND ARTERIAL ANASTOMOSES OF UPPER LIMB

A. The arteries often anastom ose or com m unicate to form networks to ensure blood sup ply distal to the joint throughout the range of m ovem ent. Art e rial o cclusio n . If a m ain channel is occluded, the sm aller alternate channels can usually increase in size, p roviding a collateral circulation that ensures the blood supply to structures distal to the blockage. However, collateral pathways require tim e to develop; they are usually insuf cient to com pensate for sudden occlusions.

SYSTEMIC OVERVIEW OF UPPER LIMB: ARTERIES

Up p e r Lim b

77

Dorsal scapular artery Teres major

Suprascapular artery Levator scapulae

Deltoid branch

Rhomboid minor

Brachial artery Profunda brachii artery (deep artery of arm)

Axillary artery Subscapular artery Circumflex scapular artery

Anastomoses with intercostal arteries

Superior ulnar collateral artery

Thoracodorsal artery Brachial artery

Collateral Middle arteries Radial

Teres major

B. Posterior View

Inferior ulnar collateral artery

Anterior

Ulnar recurrent Posterior arteries

Radial recurrent artery Ulnar artery Recurrent interosseous artery Radial artery

C. Anterior View

Common Anterior Posterior

Interosseous arteries

Radial artery

Ulnar artery

Posterior interosseous artery

Anterior interosseous artery

Anterior interosseous artery

Superficial palmar branch Radial artery Princeps pollicis

Palmar carpal arch

Dorsal carpal arch Deep palmar arch Palmar metacarpal arteries Superficial palmar arch

Perforating branches

Dorsal carpal branch Dorsalis pollicis

Dorsal digital arteries

Proper palmar digital artery gives rise to a dorsal branch Anterior View (Palmar Aspect)

Radial artery

Dorsal metacarpal arteries

Common palmar digital arteries

Radialis indicis

D

Dorsal carpal branch of ulnar artery

Dorsal branches of proper palmar digital arteries Lateral View (Isolated Third Digit)

ARTERIES AND ARTERIAL ANASTOMOSES OF UPPER LIMB (continued )

Dorsalis indicis

Posterior View (Dorsum of Hand)

2.8

B. Scap ular anastom oses. C. Anastom oses of the elbow. D. Anastom oses of the hand . Joints receive b lood from articular arteries that arise from vessels around joints.

Up p e r Lim b

78

SYSTEMIC OVERVIEW OF UPPER LIMB: VEINS AND LYMPHATICS

Suprascapular vein Cephalic vein

External jugular vein

Internal jugular vein External jugular vein

Internal jugular vein

Suprascapular vein

Subclavian vein

Thoraco-acromial vein

Right and left brachiocephalic veins

Axillary vein Posterior circumflex humeral vein

Axillary vein Posterior circumflex humeral vein

Anterior circumflex humeral vein Subscapular vein Basilic vein

Superior vena cava

Thoracodorsal vein Lateral thoracic vein Profunda brachii vein Brachial veins

Dorsal scapular vein Superior thoracic vein

Collateral veins of elbow joint

Radial recurrent vein

Anterior circumflex humeral vein Subscapular vein

Subclavian vein

Dorsal scapular vein

Circumflex scapular vein Thoracodorsal vein

Basilic vein Profunda brachii vein Brachial veins

Collateral veins of elbow joint

Anterior Ulnar recurrent veins Posterior Posterior interosseous veins

Anterior interosseous vein Radial veins Ulnar veins

Radial veins Dorsal venous network of hand Deep venous palmar arch Superficial venous palmar arch Palmar digital vein

Proper palmar digital veins

Proper palmar digital veins

A. Anterior View

2.9

B. Posterior View

OVERVIEW OF DEEP VEINS OF UPPER LIMB

Deep veins lie internal to the deep fascia and occur as p aired, continually interanastom osing accom panying veins (e.g., venae

com itantes) surrounding and sharing the nam e of the artery they accom pany.

SYSTEMIC OVERVIEW OF UPPER LIMB: VEINS AND LYMPHATICS

Up p e r Lim b

79

Apical axillary lymph nodes Deltopectoral lymph nodes Pectoralis minor muscle

To subclavian lymphatic trunk

Central axillary lymph nodes Axillary vein Humeral (lateral) axillary lymph nodes Pectoral (anterior) axillary lymph nodes Subscapular (posterior) lymph nodes Brachial veins Cephalic vein of arm

Basilic vein of arm Cubital lymph nodes Median cubital vein Basilic vein of forearm

Cephalic vein of forearm

Lymphatic plexus of palm Digital lymphatic vessels

Anterior (Palmar) View

SUPERFICIAL VENOUS AND LYMPHATIC DRAINAGE OF UPPER LIMB Super cial lym phatic vessels arise from lym phatic plexuses in the digits, palm , and dorsum of the hand and ascend with the super cial veins of the upper lim b. The super cial lym phatic vessels ascend through the forearm and arm , converging toward the cephalic and especially to the basilic vein to reach the axillary lym ph

2.10

nodes. Som e lym p h p asses through the cubital nodes at the elbow and the deltopectoral (infraclavicular) nodes at the shoulder. Deep lym phatic vessels accom pany the neurovascular bundles of the upp er lim b and end p rim arily in the hum eral (lateral) and central axillary lym ph nodes.

Up p e r Lim b

80

SYSTEMIC OVERVIEW OF UPPER LIMB: VEINS AND LYMPHATICS

Dorsal digital veins Deltoid

Dorsal digital venous arches Pectoralis major Clavipectoral (deltopectoral) triangle

Cephalic vein Superficial dorsal veins Dorsal venous network of hand

Basilic vein

Basilic vein Cephalic vein

Median cubital vein

B. Posterior View Median vein of forearm

Palmar digital veins Cephalic vein of forearm

Basilic vein of forearm Transverse anastomoses

Key Perforating veins

A. Anterior View

Basilic vein Cephalic vein

C. Anterior View

2.11

SUPERFICIAL VENOUS DRAINAGE OF UPPER LIMB

A. Forearm , arm , and pectoral region. B. Dorsal surface of hand. C. Palm ar surface of hand. Arrows indicate where p erforating veins penetrate the deep fascia. Blood is continuously shunted from

these super cial veins in the subcutaneous tissue to deep veins via the perforating veins.

SYSTEMIC OVERVIEW OF UPPER LIMB: VEINS AND LYMPHATICS

Up p e r Lim b

81

Deltoid

Clavipectoral (deltopectoral) triangle

Cephalic vein

Biceps brachii Superficial dorsal veins Cephalic vein

Basilic vein Median cubital vein Cephalic vein

Dorsal venous network of hand

Medial epicondyle

Median vein of forearm

E. Posterior View

D. Anterior View

SUPERFICIAL VENOUS DRAINAGE OF UPPER LIMB (continued ) D. Surface anatom y of veins of forearm and arm . E. Surface anatom y of veins of the dorsal surface of hand. Because of the p rom inence and accessibility of the sup er cial veins, they are com m only used for ve n ip un ct ure (p uncture of a vein to draw b lood or inject a solution). By ap plying a tourniquet to the arm , the venous return is occluded, and the veins d istend and usually are visible and/ or palpab le. Once a vein is p unctured, the tourniquet is rem oved so that when the needle is rem oved the

2.11

vein will not bleed extensively. The m edian cubital vein is com m only used for venipuncture. The veins form ing the dorsal venous network of the hand and the cep halic and basilic veins arising from it are com m only used for long-term introduction of uids (in t rave n o us fe e d in g ). The cubital veins are also a site for the in t ro d uct io n o f card iac cat h e t e rs to secure blood sam ples from the great vessels and cham bers of the heart.

82

Up p e r Lim b

SYSTEMIC OVERVIEW OF UPPER LIMB: MUSCULOFASCIAL COMPARTMENTS

Deltoid fascia Brachial fascia

Axillary fossa

Axillary fascia

Pectoral fascia Deep cervical fascia

Deep fascia over serratus anterior

Omohyoid Clavicle

Subcutaneous tissue

A. Right Anterior Oblique Views

Subclavius Costocoracoid membrane

Fascia

Pectoralis minor Pectoral fascia

Deep cervical Clavipectoral Pectoral Axillary

Pectoralis major Suspensory ligament of axilla Axillary fascia Axillary fossa

B. Lateral View of Sagittal Section

2.12

DEEP FASCIA OF UPPER LIMB—AXILLARY AND CLAVIPECTORAL FASCIA

A. Axillary fascia. The axillary fascia form s the oor of the axillary fossa and is continuous with the p ectoral fascia covering the pectoralis m ajor m uscle and the b rachial fascia of the arm . B. Clavipectoral fascia. The clavip ectoral fascia extend s from the axillary fascia to enclose the pectoralis m inor and subclavius m uscles and then attaches to the clavicle. The part of the clavipectoral fascia sup erior to the p ectoralis m inor is the costocoracoid

m em brane, and the p art of the clavip ectoral fascia inferior to the pectoralis m inor is the susp ensory ligam ent of the axilla. The suspensory ligam ent of the axilla, an extension of the axillary fascia, supp orts the axillary fascia and p ulls the axillary fascia and the skin inferior to it superiorly when the arm is abducted, form ing the axillary fossa or “arm pit.”

Up p e r Lim b

SYSTEMIC OVERVIEW OF UPPER LIMB: MUSCULOFASCIAL COMPARTMENTS

83

Fascia Anterior fascial compartment Posterior fascial compartment

Anterior Shaft of humerus

Brachial fascia Medial intermuscular septum

LATERAL

MEDIAL Lateral intermuscular septum

Deltoid fascia

Posterior

Skin

Pectoral fascia

A Interosseous membrane

Brachial fascia Anterior LATERAL Bicipital aponeurosis

Antebrachial fascia

MEDIAL Skin

Shaft of radius

Posterior

Antebrachial fascia

Palmar carpal ligament

B Palmar carpal ligament

Tendon of palmaris longus

Trapezium Superficial transverse metacarpal ligament

Palmar aponeurosis

Shaft of ulna

Flexor retinaculum Carpal tunnel Hamate

LATERAL

MEDIAL

Extensor retinaculum

Capitate

C

Right Anterior Oblique View

Trapezoid Inferior Views

DEEP FASCIA OF UPPER LIMB, BRACHIAL AND ANTEBRACHIAL FASCIA A. Brachial fascia. The brachial fascia is the deep fascia of the arm and is continuous sup eriorly with the p ectoral and axillary layers of fascia. Medial and lateral interm uscular septa extend from the deep aspect of the brachial fascia to the hum erus, dividing the arm into anterior and posterior m usculofascial com partm ents. B. Antebrachial fascia. The antebrachial fascia surrounds the forearm and is continuous with the brachial fascia and deep fascia of the hand. The interosseous m em brane separates the forearm into

2.13

anterior and posterior m usculofascial com partm ents. Distally, the fascia thickens to form the palm ar carpal ligam ent, which is continuous with the exor retinaculum and dorsally with the extensor exp ansion. The deep fascia of the hand is continuous with the antebrachial fascia, and on the palm ar surface of the hand, it thickens to form the palm ar aponeurosis. C. Flexor retinaculum (transverse carp al ligam ent). The exor retinaculum extends between the m edial and lateral carpal bones to form the carpal tunnel.

Up p e r Lim b

84

PECTORAL REGION

Supraclavicular nerves (C3 and C4) Platysma (reflected superiorly) Clavicle Deltoid Platysma

Clavipectoral (deltopectoral) triangle Cephalic vein Cephalic vein in deltopectoral groove

Pectoral fascia covering pectoralis major

Clavicular head of pectoralis major Intercostobrachial nerve (T2)

Subcutaneous tissue

Sternocostal head of pectoralis major Posterior branch of lateral pectoral cutaneous branch of intercostal nerve

Lateral mammary branches of lateral pectoral cutaneous branches of intercostal nerves

Lateral mammary branch of lateral pectoral cutaneous branches of intercostal nerve Serratus anterior Abdominal part of pectoralis major

Medial mammary branches of anterior pectoral cutaneous branches of intercostal nerves

Anterior View

2.14

SUPERFICIAL DISSECTION, MALE PECTORAL REGION

• The p latysm a m uscle, which usually descends to the 2nd or 3rd rib, is cut short on the right side and, together with the sup raclavicular nerves, is re ected on the left side. • The exposed interm uscular bony strip of the clavicle is subcutaneous and subplatysm al. • The cephalic vein p asses deep ly to join the axillary vein in the clavipectoral (deltopectoral) triangle.

• The cutaneous innervation of the pectoral region is by the supraclavicular nerves (C3 and C4) and upper thoracic nerves (T2–T6); the brachial plexus (C5–T1) does not supply cutaneous branches to the pectoral region.

PECTORAL REGION

Anterior axillary fold Deltoid

Posterior axillary fold

Deltopectoral groove

Clavipectoral (deltopectoral) triangle

Suprasternal (jugular) notch

85

Clavicle

Clavicular head of pectoralis major

Serratus anterior

Axillary fossa

Clavicle

Up p e r Lim b

Sternocostal head of pectoralis major Abdominal part of pectoralis major

SURFACE ANATOMY, MALE PECTORAL REGION The clavipectoral (deltop ectoral) triangle is the depressed area just inferior to the lateral part of the clavicle, bounded by the clavicle superiorly, the deltoid laterally, and the clavicular head of pectoralis m ajor m edially. The clavipectoral triangle and the interm uscular deltopectoral groove extending from its inferior apex dem arcate an “internervous plane” (p lane not crossed by m otor nerves) for an an t e rio r o r d e lt o p e ct o ral surg ical in cisio n to ap proach the axilla, shoulder joint, or proxim al hum erus.

2.15 When the arm is abducted and then adducted against resistance, the two heads of the pectoralis m ajor are visible and palpable. As this m uscle extends from the thoracic wall to the arm , it form s the anterior axillary fold. Digitations of the serratus anterior ap pear inferolateral to the p ectoralis m ajor. The coracoid p rocess of the scapula is covered by the anterior part of deltoid ; however, the tip of the p rocess can be felt on deep p alp ation in the clavipectoral triangle. The d eltoid form s the contour of the shoulder.

86

Up p e r Lim b

PECTORAL REGION

Intercostobrachial nerve (T2) (lateral cutaneous branch of 2nd intercostal nerve) Sternum

Pectoralis major S

S

Long thoracic nerve

Nipple

S Serratus anterior (S) Latissimus dorsi

S S

Posterior branches of lateral abdominal cutaneous branches of thoraco-abdominal nerves

S

Abdominal part of pectoralis major Anterior branches of lateral abdominal cutaneous branches of thoraco-abdominal nerves (T7, T8)

External oblique Anterior rectus sheath overlying rectus abdominis

Umbilicus Lateral cutaneous branch of iliohypogastric nerve Lateral cutaneous branch of subcostal nerve (T12)

Anterior superior iliac spine

Lateral View

2.16

SUPERFICIAL DISSECTION OF TRUNK

• The slip s of the serratus anterior interdigitate with the external oblique. • The long thoracic nerve (nerve to serratus anterior) lies on the lateral (super cial) aspect of the serratus anterior; this nerve is vulnerable to dam age from st ab wo un d s and during surgery (e.g., radical m astectom y).

• The anterior and posterior branches of the lateral thoracic and abdom inal cutaneous branches of intercostal and thoracoabdom inal nerves are dissected.

PECTORAL REGION

Up p e r Lim b

87

Axillary fossa Clavicular head of pectoralis major Posterior axillary fold Sternocostal head of pectoralis major Body of sternum

Anterior axillary fold Latissimus dorsi

Nipple

Serratus anterior

Abdominal part of pectoralis major

External oblique

External oblique

Site of anterior rectus sheath overlaying rectus abdominis Umbilicus

Linea semilunaris

Anterior superior iliac spine

Anterolateral View

SURFACE ANATOMY OF ANTEROLATERAL ASPECT OF TRUNK When the arm is abducted and then adducted against resistance, the sternocostal part of the pectoralis m ajor can be seen and palpated. If the anterior axillary fold bounding the axilla is grasped between the ngers and thum b, the inferior border of the sternocostal head

2.17

of the pectoralis m ajor can be felt. Several digitations of the serratus anterior are visible inferior to the anterior axillary fold. The posterior axillary fold is com posed of skin and m uscular tissue (latissim us dorsi and teres m ajor) bounding the axilla posteriorly.

88

Up p e r Lim b

PECTORAL REGION

Manubrium

Sternum Clavicle

Coracoid process of scapula

Clavicular head

Of pectoralis major

Sternocostal head

Pectoralis minor

Abdominal part

Pectoralis major (cut)

A

Costochondral joints

Clavicle Subclavius

B

C Anterior Views

Acromion

Clavicle

2 3 Serratus anterior

Subscapularis

4 5

Humerus

Attachment site of serratus anterior to medial border of scapula

6 7 9

8

Teres major Latissimus dorsi

D. Right Anterolateral View

2.18

E. Anterior View

PECTORALIS MAJOR AND MINOR AND SERRATUS ANTERIOR

A. Pectoralis m ajor. B. Pectoralis m inor. C. Subclavius. D. and E. Serratus anterior and its scapular attachm ent.

Up p e r Lim b

PECTORAL REGION

Deltoid

Clavicular part

Descending part of trapezius

Acromial part

89

Sternocleidomastoid Pectoralis major (clavicular head)

Jugular (suprasternal) notch

Biceps brachii (short head) Coracobrachialis Supraspinatus

Manubrium

Subscapularis Manubriosternal joint (site of sternal angle) Second costal cartilage Pectoralis major

Pectoralis major (sternocostal) head

Latissimus dorsi Teres major

Body of sternum

Pectoralis minor

Pectoralis minor Deltoid

Xiphisternal joint Anterior View

7th costal cartilage Xiphoid process

Serratus anterior

Pectoralis major

2.19

ANTERIOR ATTACHMENTS OF ANTERIOR AND POSTERIOR AXIO-APPENDICULAR AND SCAPULOHUMERAL MUSCLES

a

TABLE 2.4

ANTERIOR AXIO-APPENDICULAR MUSCLES

Muscle

Proxima l Atta chment (red)

Dista l Atta chment (blue)

Innerva tion a

Ma in Actions

Pectoralis major

Clavicular head: anterior surface of medial half of clavicle Sternocostal head: anterior surface of sternum, superior six costal cartilages Abdominal part: aponeurosis of external oblique muscle

Crest of greater tubercle of intertubercular sulcus (lateral lip of bicipital groove)

Lateral and medial pectoral nerves; clavicular head (C5 and C6 ), sternocostal head (C7 , C8 , and T1)

Adducts and medially rotates humerus at shoulder joint; draws scapula anteriorly and inferiorly Acting alone: clavicular head exes shoulder joint, and sternocostal head extends it from the exed position

Pectoralis minor

3rd to 5th ribs near their costal cartilages

Medial border and superior surface of coracoid process of scapula

Medial pectoral nerve (C8 and T1)

Stabilizes scapula by drawing it inferiorly and anteriorly against thoracic wall

Subclavius

Junction of 1st rib and its costal cartilage

Inferior surface of middle third of clavicle

Nerve to subclavius (C5 and C6)

Anchors and depresses clavicle at sternoclavicular joint

Serratus anterior

External surfaces of lateral parts of 1st to 8th–9th ribs

Anterior surface of medial border of scapula (see Fig. 2.18E)

Long thoracic nerve (C5, C6 , and C7 )

Protracts scapula and holds it against thoracic wall; rotates scapula

Numbers indicate spinal cord segmental innervation (e.g., C5 and C6 indicate that nerves supplying the clavicular head of pectoralis major are derived from 5th and 6th cervical segments of spinal cord). Boldface numbers indicate the main segmental innervation. Damage to these segments or to motor nerve roots arising from them results in paralysis of the muscles concerned.

90

Up p e r Lim b

PECTORAL REGION

Pectoralis minor Deltoid branch of thoraco-acromial artery

Acromial branches of thoraco-acromial vein and artery

Thoraco-acromial artery Lateral pectoral nerve

Clavicular branch of thoraco-acromial artery

Deltoid

Clavipectoral fascia (costocoracoid membrane) Cephalic vein Medial pectoral nerve

Clavicular head of pectoralis major

Posterior tendon

Pectoral branches of thoraco-acromial artery Sternocostal head of pectoralis major

Anterior tendon

Latissimus dorsi

Anterior View

2.20

ANTERIOR WALL OF AXILLA AND CLAVIPECTORAL FASCIA

An t e rio r wall o f axilla. The clavicular head of the pectoralis m ajor is excised, except for two cubes of m uscle that rem ain to identify the b ranches of the lateral pectoral nerve. • The clavipectoral fascia superior to the p ectoralis m inor (costocoracoid m em brane) is pierced by the cephalic vein, the lateral pectoral nerve, and the thoraco-acrom ial vessels.

• The pectoralis m inor and clavipectoral fascia are pierced by the m edial p ectoral nerve. • Observe the insertion of the pectoralis m ajor from deep to super cial: inferior part of the sternocostal head, superior part of the sternocostal head (posterior tendon), and clavicular head (anterior tendon).

AXILLA, AXILLARY VESSELS, AND BRACHIAL PLEXUS

External jugular vein Suprascapular veins

Up p e r Lim b

91

Sternocleidomastoid

Dorsal scapular vein

Pectoralis minor Cephalic vein

Omohyoid

Deltoid

Internal jugular vein

Pectoralis major

Anterior jugular vein

Axillary artery

Subclavian vein

Cephalic vein

Sternal end of clavicle Subclavius (cut end)

2nd rib

Biceps brachii Basilic vein Brachial artery Brachial veins

Axillary vein

Anterior View

VEINS OF AXILLA • The basilic vein joins the brachial veins to becom e the axillary vein near the inferior border of teres m ajor, the axillary vein becom es the subclavian vein at the lateral border of the 1st rib, and the subclavian joins the internal jugular to becom e the brachiocephalic vein posterior to the sternal end of the clavicle.

Pectoralis minor

Pectoralis major

2.21 • Num erous valves, enlargem ents in the vein, are shown. • The cephalic vein in this specim en bifurcates to end in the axillary and external jugular veins.

Up p e r Lim b

92

AXILLA, AXILLARY VESSELS, AND BRACHIAL PLEXUS

Anterior branches of lateral cutaneous branches of 2nd and 3rd intercostal nerves

Pectoralis major

Axillary sheath Coracobrachialis

Pectoralis minor Lateral cutaneous branch of 3rd intercostal nerve

Biceps brachii, short head

A

Lateral thoracic artery Serratus anterior Upper subscapular nerve

Median nerve

Long thoracic nerve Musculocutaneous nerve

Subscapularis Thoracodorsal nerve

Cephalic vein

Latissimus dorsi

Biceps brachii, long head

Thoracodorsal artery

Deltoid

Lower subscapular nerve Brachialis

Circumflex scapular artery

Coracobrachialis

Posterior branches of lateral cutaneous branches of 3rd and 4th intercostal nerves

Radial nerve Teres major

Profunda brachii artery

A. Inferior View

Lateral Heads of Medial triceps brachii Long

Nerve to long head of triceps (from radial nerve) Ulnar nerve Basilic vein Brachial artery

Apex of axilla (cervico-axillary canal)

Intercostobrachial nerves

1st rib

Clavicle

Intertubercular sulcus

Axillary Boundaries: Lateral wall

Apex Base Anterior wall Lateral wall Medial wall Posterior wall

Posterior wall

Anterior wall Base of axilla

Medial wall

B. Anterior View

2.22

WALLS AND CONTENTS OF THE AXILLA

A. Dissection. B. Location and walls of axilla. • The walls of the axilla are anterior (form ed by the pectoralis m ajor, p ectoralis m inor, and subclavius m uscles), posterior (form ed by subscapularis, latissim us dorsi, and teres m ajor m uscles), m edial (form ed by the serratus anterior m uscle), and

lateral (form ed by the intertubercular sulcus [bicipital groove] of the hum erus [concealed by the bicep s and coracobrachialis m uscles]). • The axillary sheath surrounds the nerves and vessels (neurovascular bundle) of the upper lim b.

Up p e r Lim b

AXILLA, AXILLARY VESSELS, AND BRACHIAL PLEXUS

93

ANTERIOR Coracobrachialis Coracobrachial bursa Biceps brachii Long head

Pectoralis minor

Pectoralis major Clavicle

Short head Axillary sheath

Crest of greater tubercle

Axillary artery Axillary vein

* **

Subacromial (subdeltoid) bursa LATERAL

A

Cords of brachial plexus* Long thoracic nerve

MEDIAL

Subtendinous bursa of subscapularis

Head of humerus

Glenoid labrum

Teres minor

Subscapularis Deltoid

Serratus anterior

Scapula

Subtendinous bursa of infraspinatus Infraspinatus branches of suprascapular vessels and nerve

Infraspinatus

A. Transverse Section, Inferior View

Articular cartilage of glenoid fossa of scapula

POSTERIOR

Pectoralis major Pectoralis minor

ANTERIOR

Anterior wall

ANTERIOR Axillary fat

Pectoral Medial nerve Lateral Axillary lymph nodes (green)

Lateral Intertubercular wall sulcus

Coracobrachialis Serratus anterior Medial wall

Axilla Rib

Humerus Teres major Posterior wall

Biceps brachii (short and long heads)

Axillary sheath

** *

Subscapularis

Long thoracic nerve Upper subscapular nerve

Axillary artery

Latissimus dorsi

Axillary vein

Cords of brachial plexus *

Scapula POSTERIOR

B. Transverse Section, Inferior View

POSTERIOR

C. Transverse Section, Inferior View

TRANSVERSE SECTIONS THROUGH SHOULDER JOINT AND AXILLA A. Anatomical section. B. Walls of axilla. C. Walls and contents of axilla. • The intertubercular sulcus (bicip ital groove) containing the tendon of the long head of the biceps brachii m uscle is directed anteriorly; the short head of the biceps m uscle and the coracobrachialis and pectoralis m inor m uscles are sectioned just inferior to their attachm ents to the coracoid process. • The sm all g lenoid cavity is deep ened by the glenoid labrum .

2.23

• Bursae include the subdeltoid (subacrom ial) bursa, between the deltoid and greater tubercle; the subtendinous bursa of subscapularis, between the subscapularis tendon and scapula; and coracobrachial bursa, between the coracobrachialis and subscapularis. • The axillary sheath encloses the axillary artery and vein and the three cords of the brachial plexus to form a neurovascular bundle, surrounded by axillary fat.

Up p e r Lim b

94

AXILLA, AXILLARY VESSELS, AND BRACHIAL PLEXUS

Suprascapular artery Axillary artery Thoraco-acromial artery

Cervicodorsal trunk Inferior thyroid artery Thyrocervical trunk Subclavian artery Vertebral artery Right and left common carotid arteries

Supreme thoracic artery Pectoralis minor

Brachiocephalic trunk

Circumflex Anterior humeral artery Posterior

Arch of aorta Internal thoracic artery

Subscapular artery Circumflex scapular artery Inferior border of teres major Ascending branch Thoracodorsal artery Brachial artery Profunda brachii artery Inferior ulnar collateral artery

Lateral thoracic artery

Dorsal scapular artery

Superior ulnar collateral artery

Suprascapular artery

Levator scapulae Rhomboid minor

A. Anterior View

Axillary artery Circumflex scapular branch of subscapular artery

Anastomoses with intercostal arteries

Thoracodorsal artery

2.24

ARTERIES OF PROXIMAL UPPER LIMB

B. Posterior View

Teres major

A. and B. Schem atic illustrations.

TABLE 2.5 Artery

ARTERIES OF PROXIMAL UPPER LIMB ( SHOULDER REGION AND ARM) Origin

Internal thoracic

Thyrocervical trunk

Suprascapular

a

Subclavian artery

Cervicodorsal trunk from thyrocervical trunk (or as direct branch of subclavian arterya)

Course Descends, inclining anteromedially, posterior to sternal end of clavicle and 1st costal cartilage; enters thorax to descend in parasternal plane; gives rise to perforating branches, anterior intercostal, musculophrenic, and superior epigastric arteries Ascends as a short, wide trunk, often giving rise to the suprascapular artery and/or cervicodorsal trunk and terminating by bifurcating into the ascending cervical and inferior thyroid arteries Passes inferolaterally over anterior scalene muscle and phrenic nerve, subclavian artery and brachial plexus running laterally posterior and parallel to clavicle; next passes over transverse scapular ligament to supraspinous fossa and then lateral to scapular spine (deep to acromion) to infraspinous fossa

See Weiglein AH, Moriggl B, Schalk C, et al. Arteries in the posterior cervical triangle in man. Clin Anat. 2005;18:553–557.

AXILLA, AXILLARY VESSELS, AND BRACHIAL PLEXUS

Up p e r Lim b

95

Thoraco-acromial artery Axillary artery EKG lead Circumflex humeral artery

Posterior Anterior

1

Subclavian artery

2

Catheter

Circumflex scapular artery

3

Subscapular artery

Lateral thoracic artery Deltoid branch of profunda brachii artery Profunda brachii artery (deep artery of arm)

Internal thoracic (mammary) artery

Thoracodorsal artery Brachial artery

C. Anteroposterior View 1: First part of the axillary artery between lateral border of 1st rib and medial border of pectoralis minor. 2: Second part of the axillary artery posterior to pectoralis minor. 3: Third part of the axillary artery from lateral border of pectoralis minor to inferior border of teres major, where it becomes brachial artery.

2.24

ARTERIES OF PROXIMAL UPPER LIMB (continued ) C. Axillary arteriogram .

TABLE 2.5

ARTERIES OF PROXIMAL UPPER LIMB ( SHOULDER REGION AND ARM) ( cont inued )

Artery

Origin

Course

Supreme thoracic

1st part (as only branch)

Runs anteromedially along superior border of pectoralis minor; then passes between it and pectoralis major to thoracic wall; helps supply 1st and 2nd intercostal spaces and superior part of serratus anterior

Thoraco-acromial

2nd part (medial branch)

Curls around superomedial border of pectoralis minor, pierces costocoracoid membrane (clavipectoral fascia), and divides into four branches: pectoral, deltoid, acromial, and clavicular

Lateral thoracic

2nd part (lateral branch)

Circum ex humeral (anterior and posterior)

3rd part (sometimes via a common trunk)

Encircle surgical neck of humerus, anastomosing with each other laterally; larger posterior branch traverses quadrangular space

Subscapular

3rd part (largest branch)

Descends from level of inferior border of subscapularis along lateral border of scapula, dividing within 2–3 cm into terminal branches, the circum ex scapular and thoracodorsal arteries

Circum ex scapular

Subscapular artery

Curves around lateral border of scapula to enter infraspinous fossa, anastomosing with subscapular artery

Thoracodorsal

Near its origin

Continuation of subscapular artery; accompanies thoracodorsal nerve to enter latissimus dorsi

Profunda brachii (deep brachial) artery

Near middle of arm

Superior ulnar collateral

Inferior to teres major

Accompanies ulnar nerve to posterior aspect of elbow; anastomoses with posterior ulnar recurrent artery

Inferior ulnar collateral

Superior to medial epicondyle of humerus

Passes anterior to medial epicondyle of humerus to anastomose with anterior ulnar collateral artery around elbow joint

Axillary artery

Brachial artery

Descends along axillary border of pectoralis minor; follows it onto thoracic wall, supplying lateral aspect of breast

Accompanies radial nerve through radial groove of humerus, supplying posterior compartment of arm and participating in peri-articular arterial anastomosis around elbow joint

Up p e r Lim b

96

AXILLA, AXILLARY VESSELS, AND BRACHIAL PLEXUS

Spinal ganglion (dorsal root ganglion) Three trunks—superior, middle, and inferior Three anterior divisions—superior, middle, and inferior

C5

Coracoclavicular ligament C6 C7

Coraco-acromial ligament

Anterior rami

C8 T1

Pectoralis minor

Articular disc of sternoclavicular joint

Costoclavicular ligament

Three posterior divisions Radial nerve

Medial Posterior Cords Median nerve

A. Anterior View

Lateral

Ulnar nerve

Axillary nerve

Musculocutaneous nerve

Dorsal scapular nerve

C5

Terminal branches Suprascapular nerve

Musculocutaneous nerve Radial nerve

Median nerve

Ulnar nerve Medial root of median nerve

.

Ant.

La

d cor

C7 Anterior rami

Po st

. Ant

Axillary nerve al te r

C6

r erio Sup nk tru

Lateral pectoral nerve

Lateral root of median nerve

Subclavian nerve

et Middl

runk

Pos t. d cor ior r e t Pos

ia l c Med

Post.

C8 r trunk Inferio

Ant. ord

Long thoracic nerve Medial pectoral nerve Upper subscapular nerve

Thoracodorsal nerve Lower subscapular nerve Medial cutaneous nerve of arm Medial cutaneous nerve of forearm

T1 Key Roots (anterior rami) Trunks Divisions: anterior (to flexors) or posterior (to extensors) Cords Supraclavicular branches

B. Anterior View

Infraclavicular branches Terminal branches (infraclavicular)

2.25

BRACHIAL PLEXUS

A. Dissection. B. Schem atic illustration.

AXILLA, AXILLARY VESSELS, AND BRACHIAL PLEXUS

TABLE 2.6 Nerve

Up p e r Lim b

97

BRACHIAL PLEXUS Origin

Course

Distribution/Structure(s) Supplied

Supraclavicular branche s Dorsal scapular

Anterior ramus of C5 with a frequent contribution from C4

Pierces scalenus medius, descends on deep surface of rhomboids

Rhomboids and occasionally supplies levator scapulae

Long thoracic

Anterior rami of C5–C7

Descends posterior to C8 and T1 rami and passes distally on external surface of serratus anterior

Serratus anterior

Descends posterior to clavicle and anterior to brachial plexus and subclavian artery

Subclavius and sternoclavicular joint

Passes laterally across posterior triangle of neck, through suprascapular notch deep to superior transverse scapular ligament

Supraspinatus, infraspinatus, and glenohumeral (shoulder) joint

Pierces clavipectoral fascia to reach deep surface of pectoral muscles

Primarily pectoralis major but sends a loop to medial pectoral nerve that innervates pectoralis minor

Pierces coracobrachialis and descends between biceps brachii and brachialis

Coracobrachialis, biceps brachii, and brachialis; continues as lateral cutaneous nerve of forearm

Lateral and medial roots merge to form median nerve lateral to axillary artery; crosses anterior to brachial artery to lie medial to artery in cubital fossa

Flexor muscles in forearm (except exor carpi ulnaris, ulnar half of exor digitorum profundus), 3½ thenar and lateral 2 lumbrical muscles in hand, and skin of palm and 3½ digits lateral to a line bisecting 4th digit and the dorsum of the distal halves of these digits

Passes between axillary artery and vein and enters deep surface of pectoralis minor

Pectoralis minor and part of pectoralis major

Runs along the medial side of axillary vein and communicates with intercostobrachial nerve

Skin on medial side of arm

Runs between axillary artery and vein

Skin over medial side of forearm

Subclavian Suprascapular

Superior trunk receiving bers from C5 and C6 and often C4

Infraclavicular branche s Lateral pectoral Musculocutaneous Median

Lateral cord receiving bers from C5–C7

Lateral root of median nerve is a terminal branch of lateral cord (C6, C7); medial root of median nerve is a terminal branch of medial cord (C8, T1)

Medial pectoral Medial cutaneous nerve of arm

Medial cord receiving bers from C8, T1

Medial cutaneous nerve of forearm

a

Ulnar

Terminal branch of medial cord receiving bers from C8, T1, and often C7

Passes down medial view of arm and runs posterior to medial epicondyle to enter forearm

Innervates 1½ exor muscles in forearm (see Median nerve), 1½ thenar, 2 medial lumbricals, all interossei and adductor pollicis muscles in hand, and skin of hand medial to a line bisecting 4th digit (ring nger) anteriorly and posteriorly

Upper subscapular

Branch of posterior cord receiving bers from C5

Passes posteriorly and enters subscapularis

Superior portion of subscapularis

Thoracodorsal

Branch of posterior cord receiving bers from C6 to C8

Arises between upper and lower subscapular nerves and runs inferolaterally to latissimus dorsi

Latissimus dorsi

Lower subscapular

Branch of posterior cord receiving bers from C6

Passes inferolaterally, deep to subscapular artery and vein, to subscapularis and teres major

Inferior portion of subscapularis and teres major

Axillary

Terminal branch of posterior cord receiving bers from C5 and C6

Passes to posterior aspect of arm through quadrangular space a with posterior circum ex humeral artery and then winds around surgical neck of humerus; gives rise to lateral cutaneous nerve of arm

Teres minor and deltoid, glenohumeral (shoulder) joint, and skin of superolateral arm

Radial

Terminal branch of posterior cord receiving bers from C5 to T1

Descends posterior to axillary artery; enters radial groove to pass between long and medial heads of triceps brachii

Triceps brachii, anconeus, brachioradialis, and extensor muscles of forearm; supplies skin on posterior and inferolateral aspect of arm and forearm and dorsum of hand lateral to axial line of digit 4

Quadrangular space is bounded superiorly by subscapularis and teres minor, inferiorly by teres major, medially by long head of triceps brachii, and laterally by humerus.

Up p e r Lim b

98

Cephalic vein

AXILLA, AXILLARY VESSELS, AND BRACHIAL PLEXUS

Musculocutaneous Lateral root nerve of median nerve Axillary artery

Deltoid

Pectoralis major

Lateral cord of brachial plexus Lateral pectoral nerve Coracoid process

Axillary artery (1st part)

Thoraco-acromial artery

Axillary vein Subclavius

Biceps Long head brachii Short head

1st rib

Coracobrachialis

Median nerve

Medial root of median nerve

Ulnar nerve

Medial cutaneous nerve of forearm Lower subscapular nerve Medial cord of brachial plexus Thoracodorsal nerve (to latissimus dorsi) Subscapularis Lateral thoracic artery Medial pectoral nerve Anterior View

2.26

Long thoracic nerve (to serratus anterior)

Serratus anterior

Pectoralis major (sternocostal head)

Pectoralis minor

Pectoralis major

STRUCTURES OF AXILLA: DEEP DISSECTION I

• The pectoralis m ajor m uscle is re ected, and the clavipectoral fascia is rem oved; the cube of m uscle superior to the clavicle is cut from the clavicular head of the pectoralis m ajor m uscle. • The subclavius and pectoralis m inor are the two deep m uscles of the anterior wall. • The second part of the axillary artery passes posterior to the pectoralis minor muscle, a ngerbreadth from the tip of the coracoid process; the axillary vein lies anterior and then medial to the axillary artery.

• The m edian nerve, followed proxim ally, leads by its lateral root to the lateral cord and m usculocutaneous nerve and by its m edial root to the m edial cord and ulnar nerve. These four nerves and the m edial cutaneous nerve of the forearm are derived from the anterior divisions of the brachial plexus and are raised on a stick. The lateral root of the m edian nerve m ay occur as several strands. • The m usculocutaneous nerve enters the exor com partm ent of the arm by piercing the coracobrachialis m uscle.

Up p e r Lim b

AXILLA, AXILLARY VESSELS, AND BRACHIAL PLEXUS

Subscapular artery

99

Axillary artery Medial pectoral nerve Suprascapular nerve

Pectoralis major

Lateral pectoral nerve

Circumflex Posterior humeral arteries Anterior

Subclavius Posterior cord of brachial plexus Superior thoracic artery Lateral thoracic artery (cut end) Intercostobrachial nerve Upper subscapular nerve

Basilic vein

Subscapularis Thoracodorsal nerve

Axillary nerve

Triceps brachii Posterior cutaneous nerve of arm Radial nerve

Subscapularis

Circumflex scapular artery

Long thoracic nerve

Lower subscapular nerve

Serratus anterior

Teres major Latissimus dorsi

A. Anterior View

Axillary artery (AA) Posterior circumflex humeral artery (PCH)

Teres major (TM)

PCH

AA

Subscapular artery

TM

Anastomosis (AN)

AN

PB

PCH

AN

AA

AA TM

TM PCH

PB

PB

AN

Profunda brachii artery (PB) Brachial artery (BR) BR

B. Anterior Views

59.6%

16.6%

14.5%

POSTERIOR AND MEDIAL WALLS OF AXILLA: DEEP DISSECTION II A. Dissection. The p ectoralis m inor m uscle is excised, the lateral and m edial cords of the brachial p lexus are retracted, and the axillary vein is rem oved. B. Variations of the posterior circum ex

BR

BR 6.4%

2.27

hum eral artery and profunda brachii artery. Percentages are based on 235 sp ecim ens dissected in Dr. Grant’s laboratory.

Up p e r Lim b

100

AXILLA, AXILLARY VESSELS, AND BRACHIAL PLEXUS

Musculocutaneous nerve

Quadrangular space

Posterior circumflex humeral artery Axillary nerve

Pectoralis minor Lateral cord Suprascapular nerve

Lateral cord (retracted)

Pectoralis major

Medial cord (retracted) Subclavius

Coracobrachialis Musculocutaneous nerve

Posterior divisions Posterior cord Biceps brachii (deep surface)

Upper subscapular nerve Long thoracic nerve (to serratus anterior) Subscapularis Radial nerve

Brachialis

Medial head of triceps brachii and one of its nerves

Long head of triceps brachii and its nerve

Posterior cutaneous nerve of arm Profunda brachii artery

Anterior View

2.28

Serratus anterior Thoracodorsal nerve (to latissimus dorsi)

Teres major Triangular interval Circumflex scapular artery Latissimus dorsi

Lower subscapular nerve (branch to teres major)

POSTERIOR WALL OF AXILLA, MUSCULOCUTANEOUS NERVE, AND POSTERIOR CORD: DEEP DISSECTION III

• The p ectoralis m ajor and m inor m uscles are re ected laterally; the lateral and m edial cords of the brachial plexus are re ected sup eriorly; and the arteries, veins, and m edian and ulnar nerves are rem oved. • Coracobrachialis arises with the short head of the bicep s b rachii m uscle from the tip of the coracoid process and attaches halfway down the m edial aspect of the hum erus. • The m usculocutaneous nerve p ierces the coracobrachialis m uscle and supp lies it, the biceps, and the brachialis b efore becom ing the lateral cutaneous nerve of the forearm . • The posterior cord of the plexus is formed by the union of the three posterior divisions; it supplies the three muscles of the posterior wall of the axilla and then bifurcates into the radial and axillary nerves.

• In the axilla, the radial nerve gives off the nerve to the long head of the triceps brachii m uscle and a cutaneous branch; in this sp ecim en, it also gives off a branch to the m ed ial head of the triceps. It then enters the radial groove of the hum erus with the profunda brachii (deep brachial) artery. • The axillary nerve passes through the quadrangular space along with the posterior circum ex hum eral artery. The borders of the quadrangular space are superiorly, the lateral border of the scapula; inferiorly, the teres m ajor; laterally, the hum erus (surgical neck); and m edially, the long head of triceps brachii. The circum ex scapular artery traverses the triangular interval.

AXILLA, AXILLARY VESSELS, AND BRACHIAL PLEXUS

Up p e r Lim b

101

Clavicle (lateral cut end) Acromion

Spinal accessory nerve (CN XI)

Coracoid process

Levator scapulae

Glenoid fossa Superior angle of scapula

Middle scalene

Upper subscapular nerve Triceps brachii, long head

Anterior rami of C5 and C6 Anterior scalene

Lower subscapular nerve

Subclavian artery and vein

Origin of serratus anterior from medial (vertebral) border of scapula

Clavicle (medial cut end)

Subscapularis Teres major

Intercostobrachial nerve 2nd rib

Inferior angle of scapula

Long thoracic nerve

Serratus anterior 4th rib

Posterior and anterior branches of lateral thoracic cutaneous branches of 5th intercostal nerve

Serratus posterior inferior

11th rib

A. Lateral View

8th rib

Superior angle

SERRATUS ANTERIOR AND SUBSCAPULARIS Serratus anterior

Subscapularis

Anterior View

Inferior angle

B. Sites of Muscle Attachment to Scapula

2.29

A. The serratus anterior m uscle, which form s the m edial wall of the axilla, has a eshy belly extending from the sup erior 8 or 9 ribs in the m idclavicular line to the m edial border of the scapula ( B) . Win g e d scap ula. When the serratus anterior is paralyzed because of injury to the long thoracic nerve, the m edial bord er of the scapula m oves laterally and posteriorly, away from the thoracic wall. When the arm is abducted, the m edial border and the inferior angle of the scapula pull away from the posterior thoracic wall, a deform ation known as a winged scapula. In addition, the arm cannot be abducted above the horizontal p osition b ecause the serratus anterior is unable to rotate the glenoid cavity superiorly.

102

Up p e r Lim b

SCAPULAR REGION AND SUPERFICIAL BACK

Descending (superior) part of trapezius Vertebra prominens (C7) Infraspinatus Spinal part of deltoid

Transverse (middle) part of trapezius Medial border of scapula Posterior axillary fold

Teres major Rhomboids Latissimus dorsi

Triangle of auscultation Ascending (inferior) part of trapezius

Location of thoracolumbar fascia

Site of posterior superior iliac spine

Posterior View

2.30

SURFACE ANATOMY OF SUPERFICIAL BACK

The superior b order of the latissim us dorsi and a part of the rhom boid m ajor are overlapped by the trapezius. The area form ed by the superior border of latissim us dorsi, the m edial border of the scapula, and the inferolateral border of the trapezius is called the t rian g le o f auscult at io n . This gap in the thick back m usculature is a good place to exam ine posterior segm ents of the lungs with

a stethoscope. When the scapulae are drawn anteriorly by folding the arm s across the thorax and the trunk is exed, the auscultatory triangle enlarges. The teres m ajor form s a raised oval area on the inferolateral third of the posterior aspect of the scapula when the arm is adducted against resistance. The posterior axillary fold is form ed by the teres m ajor and the tendon of the latissim us dorsi.

Up p e r Lim b

SCAPULAR REGION AND SUPERFICIAL BACK

Levator scapulae Parts of deltoid Acromial Spinal Clavicular

103

Acromion

Rhomboid minor

Deltoid:

Rhomboid major

Clavicular (anterior) part

Deltoid

Acromial (middle) part Spinal (posterior) part

Trapezius:

Deltoid tuberosity

Descending

Teres major

B. Lateral View

Transverse Ascending

Latissimus dorsi

Latissimus dorsi

Serratus posterior inferior

Teres major

Transverse processes, C1–C4 Levator scapulae Superior angle of scapula

A. Posterior View

C. Lateral View

D. Anterior View

2.31

SUPERFICIAL BACK AND DELTOID MUSCLES A. Overview. B. Deltoid. C. Levator scapulae. D. Latissim us dorsi and teres m ajor.

TABLE 2.7

SUPERFICIAL BACK ( POSTERIOR AXIO-APPENDICULAR) AND DELTOID MUSCLES

Muscle

Proxima l Atta chment

Dista l Atta chment

Innerva tion

Ma in Actions

Trapezius

Medial third of superior nuchal line; external occipital protuberance, nuchal ligament, and spinous processes of C7–T12 vertebrae

Lateral third of clavicle, acromion, and spine of scapula

Spinal accessory nerve (CN XI—motor) and cervical nerves (C3–C4—sensory)

Elevates, retracts, and rotates scapula; descending part elevates, transverse part retracts, and ascending part depresses scapula; descending and ascending part act together in superior rotation of scapula

Latissimus dorsi

Spinous processes of inferior six thoracic vertebrae, thoracolumbar fascia, iliac crest, and inferior three or four ribs

Intertubercular sulcus (bicipital groove) of humerus

Thoracodorsal nerve (C6 , C7 , C8)

Extends, adducts, and medially rotates shoulder joint; elevates body toward arms during climbing

Levator scapulae

Posterior tubercles of transverse processes of C1–C4 vertebrae

Superior part of medial border of scapula

Dorsal scapular (C5) and cervical (C3–C4) nerves

Elevates scapula and tilts its glenoid cavity inferiorly by rotating scapula

Rhomboid minor and major

Minor: inferior part of nuchal ligament and spinous processes of C7 and T1 vertebrae Major: spinous processes of T2–T5 vertebrae

Medial border of scapula from level of spine to inferior angle

Dorsal scapular nerve (C4–C5 )

Retract scapula and rotate it to depress glenoid cavity; x scapula to thoracic wall

Deltoid

Lateral third of clavicle (clavicular part), acromion (acromial part), and spine (spinal part) of scapula

Deltoid tuberosity of humerus

Axillary nerve (C5 –C6)

Clavicular (anterior) part: exes and medially rotates shoulder joint Acromial (middle) part: abducts shoulder joint Spinal (posterior) part: extends and laterally rotates shoulder joint

Up p e r Lim b

104

SCAPULAR REGION AND SUPERFICIAL BACK

Occipitalis Occipital artery Occipital lymph node Descending (superior) part of trapezius

Greater occipital nerve (posterior ramus of C2 spinal nerve) 3rd occipital nerve (posterior ramus of C3) Lesser occipital nerve (anterior ramus of C2)

Levator scapulae Rhomboid minor Rhomboid major

Cutaneous branches of posterior rami Transverse (middle) part of trapezius

Deltoid

Ascending (inferior) part of trapezius Triangle of auscultation

Subtrapezial plexus (spinal accessory nerve [CN XI] and branches of C3, C4 anterior rami)

Cutaneous branches of posterior rami

Trapezius

Latissimus dorsi

Thoracolumbar fascia

Posterior branches of lateral cutaneous branches of thoraco-abdominal nerves (anterior rami)

External oblique Lumbar triangle Gluteal fascia (covering gluteus medius)

Lateral cutaneous branch of iliohypogastric nerve (anterior ramus of L1) Cutaneous branches of posterior rami of L1 to L3 (superior clunial nerves)

Gluteus maximus

Posterior View

2.32

CUTANEOUS NERVES OF SUPERFICIAL BACK AND POSTERIOR AXIO-APPENDICULAR MUSCLES

The trapezius m uscle is cut and re ected on the left side. A super cial or rst m uscle layer consists of the trapezius and latissim us dorsi m uscles, and a second layer of the levator scapulae and rhom boids.

Cutaneous branches of posterior ram i penetrate but do not supply the super cial back m uscles.

Up p e r Lim b

SCAPULAR REGION AND SUPERFICIAL BACK TABLE 2.8

SCAPULAR MOVEMENTS

Scapula moves on the thoracic wall at the conceptual “scapulothoracic joint.” Dotted lines, starting position for each movement. Boldface, prime movers. Descending (superior) trapezius

Pectoralis minor Ascending (inferior) trapezius

Levator scapulae

Serratus anterior (inferior part)

Rhomboids Posterior View

Anterior View

A. Elevation

Posterior View

B. Depression Middle (transverse) trapezius

Pectoralis minor

Rhomboids

Superior View

Superior View

Latissimus dorsi Anterior View

Posterior View Serratus anterior

C. Protraction

D. Retraction

Descending (superior) trapezius

Levator scapulae Rhomboids

Axis of rotation Inferior trapezius

Pectoralis minor

Latissimus dorsi

Serratus anterior (inferior part) Posterior View

E. Rotation Elevating Glenoid Cavity

Anterior View

F. Rotation Depressing Glenoid Cavity

Posterior View

105

Up p e r Lim b

106

Clavicular facet of acromion Acromion Fibrous capsule of shoulder joint

ARM AND ROTATOR CUFF

Levator scapulae

Superior angle

Coracoid process

Rhomboid minor

Supraspinatus

Rhomboid major Subscapularis

Transverse humeral ligament

Lesser tubercle of humerus

Tendon of long head of biceps brachii

Subscapularis

Teres major Latissimus dorsi

A

Attachment of serratus anterior

B Inferior angle

Anterior Views

Superior angle Supraspinatus

Spine of scapula Supraspinatus Acromion Infraspinatus Teres minor

Infraspinatus

Teres minor Teres major

D C

Inferior angle Posterior Views

2.33

ROTATOR CUFF

A. and B. Subscapularis. C. and D. Sup rasp inatus, infraspinatus, and teres m inor. Four of the scapulohum eral m uscles (sup raspinatus, infrasp inatus, teres m inor, and subscapularis) are called rotator cuff m uscles

because they form a m usculotendinous rotator cuff around the glenohum eral (shoulder) joint. All except the supraspinatus are rotators of the hum erus.

Up p e r Lim b

ARM AND ROTATOR CUFF

107

Fibrous capsule of shoulder joint (overlying biceps tendon) Subscapularis tendon Deltoid (cut edge) Coracoid process

Greater tubercle Supraspinatus tendon Coracohumeral ligament

Pectoralis minor

Coraco-acromial ligament

ANTERIOR Infraspinatus tendon

Subscapularis Superior transverse scapular ligament

Clavicular facet of acromion

Acromial angle Superior angle

Deltoid (cut edge)

POSTERIOR Supraspinatus

E. Superior View

Spine of scapula

2.33

ROTATOR CUFF (continued ) E. Supraspinatus. The sup raspinatus, also p art of the rotator cuff, initiates and assists the deltoid in abducting the shoulder joint. The tendons of the rotator cuff m uscles blend with and reinforce the joint capsule of the glenohum eral joint, protecting the joint and giving it stability.

a

Injury or disease m ay dam age the rotator cuff, producing instability of the g lenohum eral joint. Rup t ure o r t e ar o f t h e sup rasp in at us t e n d o n is the m ost com m on injury of the rotator cuff. De g e n e rat ive t e n d in it is o f t h e ro t at o r cuff is com m on, especially in older people.

TABLE 2.9

SCAPULOHUMERAL MUSCLES

Muscle

Proxima l Atta chment

Dista l Atta chment

Innerva tion

Ma in Actions

Supraspinatus (S)

Supraspinous fossa of scapula

Superior facet on greater tubercle of humerus

Suprascapular nerve (C4, C5 , and C6)

Initiates abduction at shoulder joint and acts with rotator cuff musclesa

Infraspinatus (I)

Infraspinous fossa of scapula

Middle facet on greater tubercle of humerus

Suprascapular nerve (C5 and C6)

Teres minor (T)

Superior part of lateral border of scapula

Inferior facet on greater tubercle of humerus

Axillary nerve (C5 and C6)

Laterally rotates shoulder joint; helps to hold humeral head in glenoid cavity of scapula

Subscapularis (S)

Subscapular fossa

Lesser tubercle of humerus

Upper and lower subscapular nerves (C5, C6 , and C7)

Medially rotates shoulder joint and adducts it; helps to hold humeral head in glenoid cavity

Teres majorb

Posterior surface of inferior angle of scapula

Crest of lesser tubercle (medial lip of bicipital groove) of humerus

Lower subscapular nerve (C6 and C7)

Adducts and medially rotates shoulder joint

Collectively, the supraspinatus, infraspinatus, teres minor, and subscapularis muscles are referred to as the rotator cuff muscles or “SITS” muscles. They function together during all movements of the shoulder joint to hold the head of the humerus in the glenoid cavity of scapula. b Not a rotator cuff muscle.

Up p e r Lim b

108

ARM AND ROTATOR CUFF

Supraglenoid tubercle Acromion

Coracoid process

Anatomical neck (green)

Biceps brachii (short head) and coracobrachialis

Superior angle

Lesser tubercle

Suprascapular notch

Greater tubercle Crest of greater tubercle (lateral lip)

Scapula

Pectoralis minor

Supraspinatus Subscapularis

Intertubercular groove

Latissimus dorsi

Crest of lesser tubercle (medial lip)

Medial border

Surgical neck (green)

Teres major

Subscapular fossa

Pectoralis major

Infraglenoid tubercle

Triceps (long head) Subscapularis

Lateral border

Inferior angle

Serratus anterior

Deltoid

Deltoid tuberosity Coracobrachialis Humerus

Brachialis Brachioradialis

Lateral supra-epicondylar ridge

Medial supra-epicondylar ridge

Radial fossa

Coronoid fossa

Lateral epicondyle

Extensor carpi radialis longus Pronator teres

Medial epicondyle

Capitulum Trochlea

Head of radius

Common flexor origin

Common extensor origin

Brachialis

Coronoid process Tuberosity of radius

A. Anterior View

Radius

Tuberosity of ulna Ulna

Flexor digitorum superficialis

Biceps brachii and bursa

Pronator teres, ulnar head

B. Anterior View Spine of scapula

Levator scapulae

Scapula Trapezius

Acromion

2.34

Inferior belly of omohyoid Long head of biceps brachii

BONES OF PROXIMAL UPPER LIMB

A. Bony features, anterior asp ect. B. Muscle attachm ent sites, anterior aspect. C. Muscle attachm ent sites, clavicle and scapula. Fract ure s o f t h e clavicle are com m on, often caused by indirect force transm itted from an outstretched hand through the bones of the forearm and arm to the shoulder during a fall. A fracture m ay also result from a fall directly on the shoulder. The weakest part of the clavicle is at the junction of its m iddle and lateral thirds.

Supraspinatus in supraspinous fossa

Clavicle

Sternocleidomastoid (SCM)

Deltoid

C. Superior View

Coracobrachialis and short head of biceps brachii

Pectoralis major

Coracoid process

ARM AND ROTATOR CUFF Superior angle

Supraspinous fossa Spine of scapula Clavicle

Supraspinatus Trapezius

Acromioclavicular joint Acromion

Up p e r Lim b

Levator scapulae

Rhomboid minor Teres minor

Head Infraspinous fossa

Deltoid Infraspinatus

Acromial angle Greater tubercle

109

Surgical neck

Long head Infraspinatus

Triceps brachii

Lateral head Infraglenoid tubercle Rhomboid major Scapula

Teres minor

Deltoid tuberosity Deltoid Teres major

Inferior angle

Radial groove Brachialis

Humerus

Triceps brachii, medial head

Groove for ulnar nerve

Lateral supra-epicondylar ridge Triceps brachii Lateral epicondyle

Medial epicondyle

Anconeus

Head of radius

Olecranon Radius

Ulna

D. Posterior View

E. Posterior View

Acromioclavicular joint Acromion Supraglenoid tubercle

Clavicle Coracoclavicular ligament Coracoid process

Spine Supraspinous fossa Infraspinous fossa

Infraglenoid tubercle Scapula Lateral border

Inferior angle

F. Lateral View

BONES OF PROXIMAL UPPER LIMB (continued )

2.34

D. Bony features, p osterior aspect. E. Muscle attachm ent sites, posterior aspect. F. Lateral aspect of scap ula. Fract ure s o f t h e surg ical n e ck o f t h e h um e rus are esp ecially com m on in elderly peop le with o st e o p o ro sis (degeneration of bone). Even a low energy fall on the hand, with the force being transm itted up the forearm bones of the extended lim b, m ay result in a fracture. Tran sve rse fract ure s o f t h e sh aft o f h um e rus frequently result from a d irect blow to the arm . Fracture of the distal part of the hum erus, near the supra-epicondylar ridges, is a sup ra-e p ico n d ylar (sup raco n d ylar) fract ure .

Up p e r Lim b

110

Acromion process

Coracoid process

Pectoralis minor

ARM AND ROTATOR CUFF

Supraglenoid tubercle

Deltoid Biceps brachii: Short head Coracobrachialis Long head

Coracobrachialis

Glenoid fossa Brachialis

Attachment of biceps brachii to radial tuberosity Infraglenoid tubercle of scapula

Bicipital aponeurosis

A. Anterior View

B. Anterior View

Humerus Triceps brachii: Lateral head

Triceps brachii: Long head (cut) Lateral head Medial head

Long head

Long head (cut)

Medial head Attachment to olecranon process of ulna

C. Posterior View

2.35

Radial groove of humerus

D. Posterior View

ARM MUSCLES

TABLE 2.10

ARM MUSCLES

Muscle

Proxima l Atta chment

Dista l Atta chment

Innerva tion

Ma in Actions

Biceps brachii

Short head: tip of coracoid process of scapula Long head: supraglenoid tubercle of scapula and glenoid labrum

Tuberosity of radius and fascia of forearm through bicipital aponeurosis

Musculocutaneous nerve (C5, C6 , C7)

Supinates forearm and, when forearm is supine, exes elbow joint; short head exes shoulder joint; long head helps to stabilize shoulder joint during abduction.

Brachialis

Distal half of anterior surface of humerus

Coronoid process and tuberosity of ulna

Musculocutaneous nerve (C5–C7) and radial (C5–C7)

Flexes elbow joint in all positions

Coracobrachialis

Tip of coracoid process of scapula

Middle third of medial surface of humerus

Musculocutaneous nerve (C5, C6 , C7)

Assists with exion and adduction of shoulder joint

Triceps brachii

Long head: infraglenoid tubercle of scapula Lateral head: posterior surface of humerus, superior to radial groove Medial head: posterior surface of humerus, inferior to radial groove

Proximal end of olecranon of ulna and fascia of forearm

Radial nerve (C6, C7 , C8 )

Extends the elbow joint; long head steadies head of humerus when shoulder joint is abducted

Anconeus

Lateral epicondyle of humerus

Lateral surface of olecranon and superior part of posterior surface of ulna

Radial nerve (C7–T1)

Assists triceps in extending elbow joint; stabilizes elbow joint; abducts ulna during pronation

ARM AND ROTATOR CUFF

Up p e r Lim b

111

ANTERIOR (flexor compartment) Brachialis Biceps brachii

Short head

Brachial artery

Long head

Median nerve

Cephalic vein

Basilic vein Musculocutaneous nerve

MEDIAL

Lateral cutaneous nerve of forearm

LATERAL

Coracobrachialis Brachialis

Medial cutaneous nerve of forearm Medial intermuscular septum

Humerus

Superior ulnar collateral artery

Posterior cutaneous nerve of forearm

Tributary of basilic vein

Lateral intermuscular septum

Ulnar nerve

Profunda brachii artery and veins Medial head Lateral head Triceps brachii Long head

Radial nerve

A. Transverse Section POSTERIOR (extensor compartment)

Olecranon Medial epicondyle of humerus Biceps brachii Medial bicipital groove

Triceps brachii

Deltoid

Lateral head Long head Clavicular (anterior) part Spinal (posterior) part

Axillary fossa Teres major

B. Anterolateral View Latissimus dorsi

ANTERIOR AND POSTERIOR COMPARTMENTS OF ARM

2.36

A. Anatom ical section. B. Surface anatom y. • Three m uscles, the biceps brachii, brachialis, and coracobrachialis, lie in the anterior com partm ent of the arm ; the tricep s brachii lies in the posterior com p artm ent. • The m edial and lateral interm uscular sep tum separates these two m uscle groups. • The radial nerve and profunda brachii artery and veins serving the posterior com partm ent lie in contact with the radial groove of the hum erus. • The m usculocutaneous nerve serving the anterior com partm ent lies in the plane between the bicep s and the brachialis m uscles. • The m edian nerve crosses to the m edial side of the brachial artery. • The ulnar nerve passes p osteriorly onto the m edial sid e of the triceps m uscle.

112

Up p e r Lim b

ARM AND ROTATOR CUFF

Coracoid process of scapula Supraspinatus

Fibrous capsule of shoulder joint Greater tubercle of humerus

Tendon of pectoralis minor Deltoid Short head of biceps brachii

Subscapularis

Long head of biceps brachii Coracobrachialis

Pectoralis major

Teres major

Medial border of scapula Inferior angle Latissimus dorsi Biceps brachii Long head of triceps brachii Medial head

Brachialis

Brachioradialis Bicipital aponeurosis

Tendon of biceps brachii Pronator teres

Extensor muscles of forearm

Flexor muscles of forearm

A. Anterior View

2.37

MUSCLES OF ANTERIOR ASPECT OF ARM I

• The bicep s brachii has two heads: a long head and a short head. • When the elbow joint is exed app roxim ately 90 degrees, the biceps is a exor from the sup inated position of the forearm but a very powerful supinator from the pronated position.

• A triangular m em branous band, the bicipital aponeurosis, runs from the biceps tendon across the cubital fossa and m erges with the antebrachial (deep) fascia covering the exor m uscles on the m edial side of the forearm .

Up p e r Lim b

ARM AND ROTATOR CUFF

Coraco-acromial ligament

113

Coracoid process Supraspinatus

Supraspinatus

Superior angle of scapula

Fibrous capsule of shoulder joint Short head of biceps brachii

Pectoralis minor

Transverse humeral ligament Tendon of subscapularis

Subscapularis (cut edges)

Tendon of long head of biceps brachii Subscapular fossa

Pectoralis major

Coracobrachialis Teres major

Deltoid Humerus

Lateral head of triceps brachii

Inferior angle of scapula Latissimus dorsi

Long head of triceps brachii Medial head

Brachialis

Medial epicondyle of humerus

Lateral epicondyle of humerus Capitulum of humerus

Radius

Tendon of biceps brachii

Ulna

B. Anterior View

MUSCLES OF ANTERIOR ASPECT OF ARM II • The brachialis, a attened fusiform m uscle, lies p osterior (deep) to the biceps and produces the greatest am ount of exion force. • The coracobrachialis, an elongated m uscle in the sup erom edial part of the arm , is pierced by the m usculocutaneous nerve. It helps ex and adduct the shoulder joint.

2.37 • Rup ture of the tend on of the long head of the biceps usually results from wear and tear of an in amed tendon (b icep s tend initis). Normally, the tendon is torn from its attachment to the supraglenoid tubercle of the scapula. The detached muscle belly forms a ball near the center of the distal part of the anterior aspect of the arm.

114

Up p e r Lim b

ARM AND ROTATOR CUFF

Clavicular (1a) (anterior) Parts of deltoid

Acromial (1b) (middle) 1a

Spinal (1c) (posterior)

1c

1b

Long head

Triceps brachii

Lateral head (9) Biceps brachii (2)

9

* 2

Lateral bicipital groove (*)

3 Brachialis (3)

8 Triceps tendon (8) overlying medial head Brachioradialis (4) 7

4

6 Lateral epicondyle (7) Olecranon (6)

5 Extensor carpi radialis longus (5)

Fascia covering anconeus and common extensor tendon

A. Lateral View

2.38

B. Lateral View

LATERAL ASPECT OF ARM

A. Dissection . Num b ers in p aren th eses refer to structures ( B) . B. Surface an atom y. At ro p h y o f t h e d e lt o id occurs when the axillary nerve (C5 and C6) is severely dam aged (e.g., as m ig ht occur when the surgical neck of the hum erus is fractured). As the deltoid atrophies, the rounded contour of the shoulder disappears. This gives the shoulder a attened appearance and produces a slight hollow inferior to

the acrom ion. A loss of sensation m ay occur over the lateral side of the proxim al p art of the arm , the area supp lied by the superior lateral cutaneous nerve of the arm . To test the deltoid (or the function of the axillary nerve), the shoulder joint is abducted against resistance, starting from app roxim ately 15 degrees. Sup raspinatus initiates abduction at the shoulder joint.

ARM AND ROTATOR CUFF

Musculocutaneous nerve Biceps brachii Inferior ulnar collateral artery

Bicipital aponeurosis

A. Medial View

Brachialis

Brachial artery Median nerve

Coracobrachialis

Up p e r Lim b

Biceps brachii Short head Long head

115

Coracoid process Lateral cord

Posterior cutaneous nerve of arm Triceps, medial head

Triceps, long head, and its nerve

Ulnar nerve

Medial intermuscular septum

Subscapularis Teres major

Latissimus dorsi

Superior ulnar collateral artery Ulnar collateral branch of radial nerve Deltopectoral groove Brachialis

Cubital fossa

Biceps brachii

Deltoid

Anterior axillary fold

B. Medial View Basilic vein

Medial head of triceps brachii

Medial bicipital Long head of groove triceps brachii

MEDIAL ASPECT OF ARM A. Dissection. B. Surface anatom y. • The axillary artery p asses just inferior to the tip of the coracoid process and courses posterior to the coracobrachialis. At the inferior border of the teres m ajor, the axillary artery changes nam es to becom e the brachial artery and continues distally on the anterior aspect of the brachialis. • Although collateral pathways confer som e protection against gradual tem porary and partial occlusion, sudden com plete occlusion or lacerat ion o f t h e b rach ial art ery creates a surgical em ergency because paralysis of m uscles results from ischem ia within a few hours.

Posterior axillary fold

Axillary fossa

2.39 • The m edian nerve lies adjacent to the axillary and brachial arteries and then crosses the artery from lateral to m edial. • Proxim ally, the ulnar nerve is adjacent to the m edial side of the artery, passes posterior to the m edial interm uscular septum , and descends on the m edial head of triceps to pass posterior to the m edial epicondyle; here, the ulnar nerve is palpab le. • The superior ulnar collateral artery and ulnar collateral branch of the radial nerve (to m edial head of the triceps) accom pany the ulnar nerve in the arm .

116

Up p e r Lim b

ARM AND ROTATOR CUFF

Descending (superior) trapezius

Infraspinatus Rhomboids

Deltoid

Teres major Serratus anterior Long head of triceps brachii

Lateral head of triceps brachii Latissimus dorsi Medial head of triceps brachii (deep to triceps tendon) Brachioradialis

Triceps tendon Olecranon

Posterior View

2.40

SURFACE ANATOMY OF SCAPULAR REGION AND POSTERIOR ASPECT OF ARM

The three heads of the tricep s brachii form a bulge on the p osterior asp ect of the arm and are identi ab le in a lean individual when the elbow joint is extended from the exed position against resistance.

Up p e r Lim b

ARM AND ROTATOR CUFF

117

Spine of scapula

Rhomboid major

Deltoid Acromion

Infraspinatus Teres minor and nerve

Teres major

Subscapularis Axillary nerve Posterior circumflex humeral artery Serratus anterior Deltoid Medial head

Radial nerve Quadrangular space

Medial head Branches to

Triceps brachii Lateral head

Lateral head Medial head and anconeus

Inferior lateral cutaneous nerve of arm

Profunda brachii artery (deep brachial artery) Posterior cutaneous nerve of forearm Long head of triceps brachii

Triceps tendon Medial head of triceps brachii

Brachialis

Brachioradialis

Extensor carpi radialis longus

Medial epicondyle Ulnar nerve

Olecranon Triceps aponeurosis

Posterior View

TRICEPS BRACHII AND RELATED NERVES • The lateral head is re ected laterally, and the m edial head is attached to the deep surface of the triceps tendon, which attaches to the olecranon. • The rad ial nerve and profunda brachii artery pass between the proxim al attachm ents of the long and m edial heads of the tricep s brachii in the m iddle third of the arm , directly contacting the radial groove of the hum erus. • Mid arm fract ure. The m iddle third of the arm is a com m on site for fractures of the hum erus, often with associated rad ial n erve t raum a. When the radial nerve is injured in the radial groove, the

2.41 triceps brachii m uscle typically is only weakened because only the m edial head is affected. However, the m uscles in the posterior com partm ent of the forearm , supplied by m ore distal branches of the radial nerve, are paralyzed. The characteristic clinical sign of radial nerve injury is wrist d rop (inability to extend the wrist joint and ngers at the m etacarpophalangeal joints). • The axillary nerve passes through the quadrangular space along with the posterior circum ex hum eral artery. • The ulnar nerve follows the m edial border of the triceps then passes p osterior to the m edial epicondyle.

118

Up p e r Lim b

ARM AND ROTATOR CUFF

Suprascapular artery Suprascapular nerve

Infraspinatus

Supraspinatus

Fibrous capsule of glenohumeral (shoulder) joint Deltoid Teres minor Axillary nerve

Infraspinatus

Posterior circumflex humeral artery

Superior lateral cutaneous nerve of arm

Teres major

Radial nerve Profunda brachii artery (deep artery of arm) Triangular interval Triangular space Lateral head of triceps brachii

Circumflex scapular artery Quadrangular space Long head of triceps brachii

Tendon overlying medial head of triceps brachii Posterior View

2.42

DORSAL SCAPULAR AND SUBDELTOID REGIONS

• The infraspinatus m uscle, aided by the teres m inor and sp inal (posterior) bers of the deltoid m uscle, rotates the shoulder joint laterally. • The long head of the tricep s m uscle p asses between the teres m inor and teres m ajor and separates the quadrangular space from the triangular interval. • Regarding the distribution of the suprascapular and axillary nerves, each com es from C5 and C6; each supplies two m uscles— the suprascapular nerve innervates the supraspinatus and infraspinatus, and the axillary nerve innervates the teres m inor and

deltoid m uscles. Both nerves supply the shoulder joint, but only the axillary nerve has a cutaneous branch. • Axillary n e rve in jury m ay occur when the glenohum eral (shoulder) joint dislocates because of its close relation to the inferior part of the joint capsule. Subglenoid displacem ent of the head of the hum erus into the q uadrangular sp ace m ay dam age the axillary nerve. Axillary nerve injury is indicated by paralysis of the deltoid and sensory loss over the lateral side of the proxim al part of the arm .

Up p e r Lim b

ARM AND ROTATOR CUFF

119

Superficial cervical artery Spinal accessory nerve (CN XI) Suprascapular artery Suprascapular nerve

Descending (superior) part of trapezius

Coracoclavicular (conoid) ligament Omohyoid

Clavicle Supraspinatus (covered with deep fascia)

Rhomboid minor

Acromion

Levator scapulae Superior angle of scapula

Deltoid

Transverse (middle) part of trapezius

Crest of spine of scapula

Superior transverse scapular ligament Ascending (inferior) part of trapezius

Serratus anterior

A. Posterior View Dorsal scapular artery Vertebral artery Subclavian artery Internal thoracic artery Levator scapulae Superior transverse scapular ligament

Thyrocervical trunk

Suprascapular artery

Levator scapulae

Cervicodorsal trunk Dorsal scapular artery Suprascapular artery Suprascapular nerve

Rhomboid minor

Clavicle

Axillary artery

Acromion

Dorsal scapular nerve

Subscapular artery

Anastomoses with intercostal arteries

Dorsal scapular artery

Circumflex scapular branch

Supraspinatus (cut end)

B

Posterior Views

SUPRASCAPULAR REGION A. Dissection. At the level of the superior ang le of the scapula, the transverse part of the trapezius m uscle is re ected. B. Suprascapular and dorsal scapular arteries. C. Scap ular anastom osis. Several arteries join to form anastom oses on the anterior and posterior surfaces of the scapula. The im portance of the collateral circulation m ade possible by these anastom oses becom es apparent

C

Teres major

Thoracodorsal artery

2.43 when lig at io n of a lace rat e d sub clavian o r axillary art e ry is necessary or there is occlusion of these vessels. The direction of blood ow in the subscapular artery is then reversed, enabling blood to reach the third part of the axillary artery. In contrast to a sudden occlusion, slow occlusion of an artery often enables suf cient lateral circulation to develop , preventing isch e m ia (de ciency of blood).

Up p e r Lim b

120

JOINTS OF SHOULDER REGION

Coracoclavicular ligament

Superior acromioclavicular ligament

Trapezoid

Conoid

Anterior sternoclavicular ligament Interclavicular ligament 1st rib Clavicle

Transverse humeral ligament

Coracoid process Coraco-acromial ligament Fibrous capsule of glenohumeral (shoulder) joint

Subscapularis

Costoclavicular ligament

A. Anterior View

Articular disc of sternoclavicular joint

Winging of scapula to change plane of glenohumeral (shoulder) joint

Manubrium

Pectoralis minor

Short Biceps head brachii Long head

Thoracic wall

Key Protracted

50°

Retracted 30°

Acromioclavicular joint

30° 40°

30°

B. Superior View

2.44

Winging of scapula Rotation during protraction and retraction of scapula on thoracic wall

Frontal plane Sternoclavicular joints

PECTORAL GIRDLE

A. Dissection. B. Clavicular m ovem ents at the sternoclavicular and acrom ioclavicular joints during rotation, protraction, and retraction of the scapula on the thoracic wall and winging of the scap ula. • The shoulder region includes the sternoclavicular, acrom ioclavicular, and shoulder (glenohum eral) joints; the m obility of the clavicle is essential to the m ovem ent of the up per lim b. • The sternoclavicular joint is the only joint connecting the upper lim b (app endicular skeleton) to the trunk (axial skeleton).

The articular disc of the sternoclavicular joint divides the joint cavity into two parts and attaches superiorly to the clavicle and inferiorly to the rst costal cartilage; the disc resists superior and m edial disp lacem ent of the clavicle. Paralysis o f se rrat us an t e rio r. Note that when the serratus anterior is paralyzed because of injury to the long thoracic nerve ( B) , the m edial border of the scapula m oves laterally and posteriorly away from the thoracic wall, giving the scapula the appearance of a wing (win g e d scap ula). See Clinical Com m ent for Figure 2.29.

JOINTS OF SHOULDER REGION

Up p e r Lim b

121

Supraspinatus Deltoid

Acromial branches of suprascapular artery

Cut edge of subacromial bursa

Clavicle

Acromial angle

Coracoid process

Acromial branch of thoraco-acromial artery Acromioclavicular ligament Coracoid process Coraco-acromial ligament

Perforation Supraspinatus tendon blended with fibrous capsule of glenohumeral joint

Tendon of long head of biceps brachii

Perforation

Cut edge of subacromial bursa

Teres minor

Subacromial bursa

Deltoid Tendon of long head of biceps brachii

A. Superolateral View

B. Lateral View

Coracoclavicular ligament

Coracoid process

Articular disc Articular capsule

Clavicle

Coronal Section

Acromion

Acromial facet Acromion

Clavicle

Articular capsule

C. Superior Views

SUBACROMIAL BURSA AND ACROMIOCLAVICULAR JOINT A. Subacrom ial bursa. The bursa has been injected with purp le latex. B. Acrom ioclavicular joint. C. Attrition of sup rasp inatus tendon. As a result of wearing away of the supraspinatus tendon and underlying capsule, the subacrom ial bursa and shoulder joint com e into com m unication. The intracapsular part of the tendon of the long head of biceps m uscle becom es frayed, leaving it adherent

2.45

to the intertubercular groove. Of 95 dissecting room subjects in Dr. Grant’s lab, none of the 18 younger than 50 years of age had a perforation, but 4 of the 19 who were 50 to 60 years and 23 of the 57 older than 60 years had perforations. The perforation was bilateral in 11 subjects and unilateral in 14.

122

Up p e r Lim b

JOINTS OF SHOULDER REGION Acromion process Coraco-acromial ligament Spine of scapula Coracoid process

Tendon of supraspinatus (cut) Fibrous capsule of shoulder joint

Suprascapular notch

Greater tubercle Transverse humeral ligament Communication between synovial cavity and subtendinous bursa of subscapularis

Intertubercular tendon sheath

Surgical neck of humerus

Tendon of long head of biceps brachii

A. Anterior View

Fibrous capsule of shoulder joint Lateral border of scapula Tendon of subscapularis (cut)

Superior acromioclavicular ligament

Synovial membrane of shoulder joint (distended with purple fluid) Clavicle

Greater tubercle Transverse humeral ligament Intertubercular tendon sheath

Conoid ligament

Parts of coracoclavicular Trapezoid ligament ligament

Tendon of long head of biceps brachii Subtendinous bursa of subscapularis

B. Anterior View

2.46

Coraco-acromial ligament

LIGAMENTS AND ARTICULAR CAPSULE OF GLENOHUMERAL (SHOULDER) JOINT

A. Fibrous capsule. • The loose brous capsule is attached to the m argin of the glenoid cavity and to the anatom ical neck of the hum erus. • The strong coracoclavicular ligam ent p rovides stability to the acrom ioclavicular joint and prevents the scapula from being

driven m edially and the acrom ion from being driven inferior to the clavicle. • The coraco-acrom ial ligam ent prevents superior displacem ent of the head of the hum erus.

JOINTS OF SHOULDER REGION

Up p e r Lim b

123

Acromion Coraco-acromial ligament Fibrous capsule Biceps brachii, long head

Superior glenohumeral ligament

Middle glenohumeral ligament

Glenoid cavity Synovial fringe

Surgical neck of humerus

Glenoid labrum Tendon of subscapularis

Inferior glenohumeral ligament Anatomical neck of humerus

C. Postero-inferior View

LIGAMENTS AND ARTICULAR CAPSULE OF GLENOHUMERAL (SHOULDER) JOINT (continued ) B. Synovial m em brane of joint capsule. The synovial m em brane lines the brous capsule and has two prolongations: (1) where it form s a synovial sheath for the tendon of the long head of the biceps m uscle in its osseo brous tunnel and (2) inferior to the coracoid process, where it form s a bursa between the subscapularis tendon and m argin of the glenoid cavity—the sub tendinous bursa of the subscapularis. C. Glenohum eral ligam ents viewed from the interior of the shoulder joint. • The joint is exposed from the posterior aspect b y cutting away the thinner postero-inferior part of the capsule and sawing off the head of the hum erus. • The glenohum eral ligam ents are visible from within the joint but are not easily seen externally. • The glenohum eral ligam ents and tendon of the long head of biceps brachii m uscle converge on the supraglenoid tubercle.

2.46

• The slender superior glenohum eral ligam ent lies parallel to the tendon of the long head of biceps brachii. The m iddle ligam ent is free m edially because the subtendinous bursa of subscapularis com m unicates with the joint cavity; usually, there is only a single site of com m unication. In this individual, there are openings on both sides of the ligam ent. Because of its freedom of m ovem ent and instability, the glenohum eral joint is com m only dislocated by direct or indirect injury. Most d islocat ion s of t h e h um eral h ead occur in the downward (inferior) direction but are described clinically as anterior or (m ore rarely) posterior dislocations, indicating whether the hum eral head has descended anterior or posterior to the infraglenoid tubercle and the long head of triceps. Anterior dislocation of the glenohum eral joint occurs m ost often in young adults, particularly athletes. It is usually caused by excessive extension and lateral rotation of the hum erus.

124

Up p e r Lim b

JOINTS OF SHOULDER REGION

Supraspinatus tendon and capsule of shoulder joint Subacromial bursa

Tendon of long head of biceps brachii

Openings into subtendinous bursa of subscapularis Deltoid Infraspinatus

Superior glenohumeral ligament Subscapularis tendon

Teres minor

Biceps brachii (short head) Middle glenohumeral ligament

Site of origin of long head of triceps brachii (infraglenoid tubercle)

Inferior glenohumeral ligament Axillary nerve Posterior circumflex humeral artery

Supraspinatus

Tendon of long head of biceps brachii

Subscapularis Subscapularis

Tendons of rotator cuff

Head of humerus (covered with articular cartilage)

Infraspinatus Teres minor

A. Lateral View Site of origin of teres major

Deltoid Glenoid labrum Infraspinatus

Glenoid cavity

Humerus

Teres minor Subscapularis

B. Lateral View

2.47

INTERIOR OF GLENOHUMERAL (SHOULDER) JOINT AND RELATIONSHIP OF ROTATOR CUFF

A. Dissection. B. Schem atic illustration. • The subacrom ial bursa is between the acrom ion and deltoid sup eriorly and the tendon of sup raspinatus inferiorly. • The four short rotator cuff m uscles (sup raspinatus, infraspinatus, teres m inor, and subscapularis) cross the glenohum eral joint and blend with the cap sule. • The axillary nerve and p osterior circum ex hum eral artery are in contact with the capsule inferiorly and m ay be injured when the glenohum eral joint dislocates.

• In am m ation and calci cation of the subacrom ial bursa result in pain, tenderness, and lim itation of m ovem ent of the glenohum eral joint. This condition is also known as calci c scap ulo h um e ral b ursit is. Deposition of calcium in the supraspinatus tendon m ay irritate the overlying subacrom ial bursa, producing an in am m atory reaction, sub acro m ial b ursit is.

JOINTS OF SHOULDER REGION

Joint capsule of acromioclavicular joint

Up p e r Lim b

125

Coraco-acromial ligament

Acromion

Clavicle

Supraglenoid tubercle

Glenoid labrum

Coracoid process Coracohumeral ligament

Glenoid cavity

Tendon of long head of biceps brachii

Long head of triceps brachii

Supraspinatus Lateral border of scapula

Rotator cuff

Infraspinatus

Teres minor Subscapularis

Inferior angle of scapula

C. Lateral View

D. Lateral View

INTERIOR OF GLENOHUMERAL (SHOULDER) JOINT AND RELATIONSHIP OF ROTATOR CUFF (continued ) C. Dissection. D. Schem atic illustration of the rotator cuff m uscles and their relationship to the glenoid cavity. • The coraco-acrom ial arch (coracoid process, coraco-acrom ial ligam ent, and acrom ion) p revents sup erior displacem ent of the head of the hum erus. • The long head of the triceps brachii m uscle arises just inferior to the glenoid cavity; the long head of biceps just superior to it. • The m ain function of the m usculotendinous rotator cuff is to hold the large head of the hum erus in the sm aller and shallow

2.47

glenoid cavity of the scapula, both during the relaxed state (by tonic contraction) and during active abduction. Te arin g o f t h e b ro cart ilag in o us g le n o id lab rum com m only occurs in the athletes who throw (e.g., a baseball) and in those who have shoulder instability and subluxation (p artial dislocation) of the glenohum eral joint. The tear often results from sudden contraction of the biceps or forceful subluxation of the hum eral head over the glenoid labrum . Usually, a tear occurs in the anterosuperior p art of the labrum .

Up p e r Lim b

126

Acromion

JOINTS OF SHOULDER REGION

Acromioclavicular joint

Spine of scapula

Tubercle of 1st rib

Clavicle

1st rib

Greater tubercle

Coracoid process

Deltoid muscle Vertebral border of scapula Head of humerus Infraglenoid tubercle

Rim of glenoid fossa

Surgical neck of humerus

Lateral border of scapula

A. Anteroposterior View Acromioclavicular joint Acromion

Clavicle

Subacromial bursa

Tendon of long head of biceps brachii

Fibrous capsule

Supraglenoid tubercle Articular cartilage

Joint cavity

Scapula Greater tubercle

Joint cavity

Humerus Glenoid labrum

Fibrous capsule Joint capsule

B. Coronal Section

2.48

Bicipital groove of humerus

Synovial membrane

IMAGING OF GLENOHUMERAL (SHOULDER) JOINT

A. Radiograph. B. Sectioned joint to show location of subacrom ial bursa and joint cavity.

Up p e r Lim b

JOINTS OF SHOULDER REGION

127

TR C A

3 SP

12

SV

2

GF

GT

3

H S

12 1

10

11

LB SB D

D. Transverse Scan

TM QS

C D, E, F

C. Coronal MRI

Lesser tubercle (10) Transverse humeral ligament (12) 10

Tendon of long head of biceps brachii (1)

3

Head of humerus (9)

Greater tubercle (2)

2 1

Bicipital groove (11)

9

Glenoid fossa (7)

Subacromial bursa

Subscapularis (6)

7 7 3

6

4 Deltoid (3)

5 8

Scapula (8)

Glenoid labrum (4)

3

Infraspinatus (5) and subtendinous bursa

8

E. Transverse MRI

F. Transverse Section, Inferior View

IMAGING OF GLENOHUMERAL (SHOULDER) JOINT (continued ) C. Coronal MRI. A, acrom ion; C, clavicle; D, deltoid; GF, glenoid cavity; GT, crest of greater tubercle; H, head of hum erus; LB, long head of biceps brachii; QS, quadrangular space; S, scap ula; SB, sub scap ularis; SP, supraspinatus; SV, suprascapular vessels and

Infraspinatus branches of suprascapular vessels and nerves

2.48

nerve; TM, teres m inor; TR, trapezius. D. Transverse ultrasound scan of area indicated ( F) . E. Transverse MRI with contrast ag ent. F. Transverse section. Num bers ( F) refer to structures lab eled in D and E.

Up p e r Lim b

128

ELBOW REGION

SUPERIOR

LATERAL

MEDIAL

INFERIOR

Brachial fascia Biceps brachii

1

Cephalic vein (1)

Medial cutaneous nerve of forearm

Basilic vein (3)

3 Cubital lymph node

Lateral cutaneous nerve of forearm Medial epicondyle

4

1

Median cubital vein (4)

Biceps brachii tendon

Basilic vein of forearm (3)

Antebrachial fascia

Perforating vein

3

Bicipital aponeurosis Median vein of forearm (2)

2 Cephalic vein of forearm (1)

A. Anterior View

B. Anterior View

2.49

CUBITAL FOSSA: SURFACE ANATOMY AND SUPERFICIAL DISSECTION

A. Surface anatom y. B. Cutaneous nerves and super cial veins. Num bers in parentheses refer to structures ( A) . • The cub ital fossa is a triangular space (com p artm ent) inferior to the elbow crease, roofed by deep fascia. • In the forearm , the super cial veins (cephalic, m edian, basilic, and their connecting veins) m ake a variable, M-shaped pattern. • The cep halic and basilic veins occupy the bicip ital grooves, one on each side of the biceps brachii. In the lateral bicip ital groove,

the lateral cutaneous nerve of the forearm appears just superior to the elbow crease; in the m edial bicipital groove, the m edial cutaneous nerve of the forearm becom es cutaneous at ap proxim ately the m idpoint of the arm . • The cubital fossa is the com m on site for sam p lin g an d t ran sfusio n o f b lo o d an d in t rave n o us in je ct io n s because of the prom inence and accessibility of veins. Usually, the m edian cubital vein or basilic vein is selected.

ELBOW REGION

Up p e r Lim b

129

SUPERIOR

LATERAL

MEDIAL

INFERIOR Subcutaneous tissue

Brachial fascia

Basilic vein

Fascia covering biceps brachii Biceps brachii

Branch of superior ulnar collateral artery

Brachialis Inferior ulnar collateral artery Brachial artery and veins Lateral cutaneous nerve of forearm (from musculocutaneous nerve)

Brachioradialis

Medial epicondyle Median nerve Pronator teres

Biceps brachii tendon Perforating vein

Bicipital aponeurosis

Antebrachial fascia

C. Anterior View

CUBITAL FOSSA: DEEP DISSECTION I (continued ) C. Boundaries and contents of the cubital fossa. • The cub ital fossa is bound laterally by the brachioradialis and m edially by the pronator teres and superiorly by a line joining the m edial and lateral epicondyles. • The three chief contents of the cubital fossa are the bicep s brachii tendon, brachial artery, and m edian nerve. • The biceps brachii tendon, on app roaching its insertion, rotates through 90 degrees, and the bicipital aponeurosis extends m edially from the proxim al p art of the tendon.

2.49 • A fracture of the distal part of the hum erus, near the supraepicondylar ridges, is called a sup ra-e p ico n d ylar (sup racon d ylar) fract ure. The distal bone fragm ent m ay be displaced anteriorly or posteriorly. Any of the nerves or branches of the brachial vessels related to the hum erus m ay be injured by a displaced bone fragm ent.

130

Up p e r Lim b

ELBOW REGION

SUPERIOR

LATERAL

MEDIAL

INFERIOR Biceps brachii

Musculocutaneous nerve

Medial intermuscular septum

Brachialis Inferior ulnar collateral artery Radial nerve Ulnar nerve Brachial artery Brachioradialis Median nerve Biceps brachii tendon Extensor carpi radialis longus Deep branch of radial nerve Radial recurrent artery Extensor carpi radialis brevis Superficial branch of radial nerve

Superficial head of pronator teres Ulnar artery Deep head of pronator teres Supinator Flexor carpi radialis

Radial artery

D. Anterior View

2.49

CUBITAL FOSSA: DEEP DISSECTION II

D. Floor of the cubital fossa. • Part of the bicep s brachii m uscle is excised, and the cub ital fossa is op ened widely, exposing the brachialis and sup inator m uscles in the oor of the fossa. • The d eep branch of the radial nerve pierces the sup inator. • The brachial artery lies between the biceps tendon and m edian nerve and divides into two branches, the ulnar and radial arteries.

• The m edian nerve supplies the exor m uscles. With the exception of the twig to the deep head of pronator teres, its m otor branches arise from its m edial side. • The radial nerve supplies the extensor m uscles. With the exception of the twig to brachioradialis, its m otor branches arise from its lateral side. In this specim en, the radial nerve has been displaced laterally, so here its lateral branches appear to run m edially.

ELBOW REGION

Up p e r Lim b

131

Tendon of long head of biceps brachii attached to intertubercular groove

Biceps brachii Ulnar nerve Superior ulnar collateral artery

Humerus Long head

Hypertrophic margin of head of humerus Biceps brachii

Brachial artery

Superior coracobrachialis

Short head

Musculocutaneous nerve

Supracondylar process

Short head of biceps brachii Median nerve Coracobrachialis

Pronator teres

Attrition of long head of biceps brachii tendon

3rd head of biceps brachii

A. Anterior View Supracondylar process

Brachialis

C. Anterior View

B. Anterior View

Teres major

Basilic vein Cephalic vein

Median nerve

Brachial artery

Brachial artery Biceps brachii

Brachial artery

Antebrachial fascia

Ulnar artery Communicating branch from musculocutaneous nerve Median nerve

Superficial ulnar artery

Radial artery

Radial artery

5%

82%

13%

F. Anterior Views D. Anterior View

ANOMALIES A. Supracondylar p rocess of hum erus. A brous band, from which the p ronator teres m uscle arises, joins this sup ra-epicondylar p rocess to the m edial epicondyle. The m edian nerve, often accom panied by the brachial artery, passes through the foram en form ed by this band. This m ay be a cause of nerve entrap m ent. B. Third head of biceps b rachii. In this case, there is also attrition of the biceps tendon. C. Attrition of the tendon of the long head of biceps brachii and presence of a coracobrachialis. D. Super cial ulnar artery.

E. Anteromedial View

2.50 E. Anom alous division of brachial artery. In this case, the m edian nerve passes between the radial and ulnar arteries, which arise high in the arm . F. Relationship of m edian nerve and brachial artery. The variable relationship of these two structures can be exp lained develop m entally. In a study of 307 lim bs in Dr. Grant’s lab, portions of both prim itive brachial arteries persisted in 5%, the posterior in 82%, and the anterior in 13%.

Up p e r Lim b

132

ELBOW REGION

SUPERIOR

MEDIAL

LATERAL

INFERIOR

2 Triceps tendon (2)

5

Brachioradialis (3)

3

1 Medial epicondyle 4

6

Extensor carpi radialis longus (4)

Ulnar nerve Posterior ulnar recurrent artery Tendinous arch of cubital tunnel

Lateral epicondyle (5) Common extensor tendon

Olecranon (1) Aponeurosis of flexor carpi ulnaris blended with antebrachial fascia

Fascia covering anconeus

Anconeus (6)

A. Posterior View B. Posterior View

2.51

POSTERIOR ASPECT OF ELBOW I

A. Surface anatom y. B. Super cial dissection. Num bers in parentheses refer to structures ( A) . • The triceps brachii is attached distally to the sup erior surface of the olecranon and, through the deep fascia covering the anconeus, into the lateral border of olecranon.

• The posterior surfaces of the m edial epicondyle, lateral epicondyle, and olecranon are subcutaneous and palpable. • The ulnar nerve, also palpable, runs subfascially posterior to the m edial ep icondyle; distal to this point, it disap pears deep to the two heads of the exor carpi ulnaris.

ELBOW REGION

Up p e r Lim b

133

SUPERIOR Triceps brachii MEDIAL

LATERAL

INFERIOR Medial intermuscular septum

Lateral intermuscular septum

Olecranon Ulnar nerve

Anconeus (retracted)

Medial epicondyle

Medial collateral ligament Tendinous arch of cubital tunnel (humeral part) Flexor digitorum superficialis

Extensor carpi ulnaris Radial collateral ligament Tendinous arch of cubital tunnel (ulnar part) Anular ligament

Posterior ulnar recurrent artery

Flexor digitorum profundus

Flexor carpi ulnaris

Interosseous recurrent artery

Anconeus (cut surface)

Supinator Posterior interosseous nerve Extensor carpi ulnaris

Posterior View

POSTERIOR ASPECT OF ELBOW II Deep d issect ion . The distal portion of the triceps brachii m uscle was rem oved. Note that the ulnar nerve descends subfascially within the posterior com partm ent of the arm , passing posterior to the m edial epicondyle in the groove for the ulnar nerve. Next, it passes posterior to the ulnar collateral ligam ent of the elbow joint and then between the exor carpi ulnaris and exor digitorum profundus m uscles. Uln ar n e rve in jury occurs m ost com m only where the nerve passes posterior to the m edial epicondyle of the hum erus. The injury

2.52 results when the m edial p art of the elbow hits a hard surface, fracturing the m edial epicondyle. The ulnar nerve m ay be com pressed in the cubital tunnel, resulting in cub it al t un n e l syn d rom e. The cubital tunnel is form ed by the tendinous arch joining the hum eral and ulnar heads of attachm ent of the exor carpi ulnaris m uscle. Ulnar nerve injury can result in extensive m otor and sensory loss to the hand.

Up p e r Lim b

134

ELBOW JOINT

Lateral supra-epicondylar ridge

Lateral supra-epicondylar ridge

Medial supra-epicondylar ridge

Radial fossa

Olecranon fossa

Coronoid fossa Medial epicondyle (common flexor origin)

Lateral epicondyle (common extensor origin)

Trochlea

Capitulum Trochlear notch

Neck Subtendinous Tuberosity bursa Biceps brachii

Extensor Lateral attachment epicondyle Captitulum

Trochlea

Olecranon Cutaneous triangular surface for olecranon bursa

Radial notch Head

Flexor Medial attachment epicondyle Groove for ulnar nerve

Tubercle on coronoid process Tuberosity of ulna Supinator fossa

Head Neck

Supinator crest

Tuberosity

Posterior border

Anterior oblique line

Posterior oblique line

A. Anterior View

B. Posterior View

Triceps brachii

Lateral supraepicondylar ridge Olecranon fossa Lateral epicondyle Capitulum

Medial supra-epicondylar ridge

Fibrous capsule Fat pad Medial epicondyle Olecranon

Trochlea of humerus

Synovial membrane

Trochlea

Head of radius

Coronoid process

Neck of radius

Proximal radio-ulnar joint

Tuberosity of radius

Brachialis

Ulna

C. Anteroposterior View

Olecranon Bursae

Coronoid process of ulna

Subtendinous Intratendinous Subcutaneous

D. Sagittal Section Lateral View

2.53

BONES AND IMAGING OF ELBOW REGION

A. Anterior bony features. B. Posterior bony features. C. Radiograph of elbow joint. D. Section of hum ero-ulnar joint. The subcutaneous olecranon bursa is exposed to injury during falls on the elbow and to infection from abrasions of the skin covering the olecranon. Repeated excessive pressure and friction produces a friction sub cut an e ous o le cran on b ursit is (e.g., “student’s elbow”).

Sub t en d in ous ole cran on b ursit is results from excessive friction between the triceps tendon and the olecranon. For exam ple, it m ay occur due to repeated exion-extension of the forearm during certain assem bly-line jobs. The pain is severe during exion of the forearm because of pressure exerted on the in am ed subtendinous olecranon bursa by the triceps tendon.

ELBOW JOINT

Up p e r Lim b

135

PR U

R

PR

U

R

Axis of rotary movement U

Proximal radio-ulnar joint (PR) Anular ligament of radius

Proximal radio-ulnar joint (PR) Pronator teres

Pronator teres

Radius (R)

Distal radio-ulnar joint (DR)

Radius (R)

R

Ulna (U) Pronator quadratus

R

U

DR

Pronator quadratus

DR

A. Anterior View, Supination

Distal radio-ulnar joint (DR)

B. Anterior View, Pronation

SUPINATION AND PRONATION AT SUPERIOR, MIDDLE, AND INFERIOR RADIO-ULNAR JOINTS A. Radiograp h of forearm in sup ination. B. Radiograph of forearm in p ronation. The radius crosses the ulna when the forearm is pronated. The superior and inferior radio-ulnar joints are synovial

Ulna (U)

2.54

joints; the m iddle radio-ulnar joint is a syndesm osis ( brous joint) in which the interosseous m em brane connects the forearm bones.

Up p e r Lim b

136

ELBOW JOINT

Humerus Biceps brachii tendon

Anular ligament of radius

Oblique cord Interosseous membrane

Medial epicondyle

Radius

Anterior band Posterior band

of ulnar collateral ligament

Oblique band Olecranon

A. Medial View Ulna

Tubercle for ulnar collateral ligament

Humerus Triceps brachii: Medial head Aponeurosis

Brachioradialis Joint capsule Capitulum of humerus

Trochlea of humerus Olecranon of ulna

Head of radius

Neck Tuberosity

Trochlear notch of ulna

Ulna

B. Oblique MRI

2.55

MEDIAL ASPECT OF BONES AND LIGAMENTS OF ELBOW REGION

A. Ligam ents. The anterior band of the ulnar (m edial) collateral ligam ent is a strong, round cord that is taut when the elbow joint

is extended. The posterior band is a weak fan that is taut in exion of the joint. B. MRI of elbow joint.

ELBOW JOINT

Up p e r Lim b

137

Humerus Capitulum

Lateral supra-epidondylar ridge

Head of radius Tuberosity of radius Neck of radius

Lateral epicondyle

Trochlear notch Olecranon

A. Lateral View Radial collateral ligament

Anular ligament of radius

Interosseous membrane

Ulna

Head of radius Supra-epicondylar ridge

Neck of radius

Triceps brachii Tuberosity of radius Trochlea Ulna

Trochlear notch Olecranon

B. Lateral View

LATERAL ASPECT OF BONES AND LIGAMENTS OF ELBOW REGION A. Lig am ents. The fan-shaped radial (lateral) collateral lig am ent is prim arily attached to the anular ligam ent of the radius; super cial

2.56

bers of the lateral ligam ent blend with the brous capsule and continue onto the radius. B. Lateral radiograp h.

138

Up p e r Lim b

ELBOW JOINT

Humerus

Lateral epicondyle

Synovial membrane of elbow joint

Anular ligament of radius Sacciform recess Ulna

Radius

A. Anterior View

POSTERIOR Olecranon

Nonarticular area overlaid with synovial pad of fat Radial notch of ulna

Synovial fat pad

Radial collateral ligament

Oblique part of ulnar collateral ligament Synovial fold Coronoid process (articular surface)

Anular ligament of radius

B. Superior View

2.57

ANTERIOR

SYNOVIAL CAPSULE OF ELBOW JOINT AND ANULAR LIGAMENT

A. Synovial cap sule of elbow and proxim al radio-ulnar joints. The cavity of the elbow was injected with purple uid (wax). The brous capsule was rem oved, and the synovial m em brane rem ains. B. Anular ligam ent. • The anular ligam ent secures the head of the radius to the radial notch of the ulna and with it form s a tap ering colum nar socket (i.e., wide superiorly, narrow inferiorly). • The anular ligam ent is bound to the hum erus by the radial collateral ligam ent of the elbow.

A com m on childhood injury is sub luxat io n an d d islo cat io n o f t h e h e ad o f t h e rad ius after traction on a pronated forearm (e.g., when lifting a child onto a bus). The sudden pulling of the upper lim b tears or stretches the distal attachm ent of the less tapering anular ligam ent of a child. The radial head then m oves distally, partially out of the anular ligam ent. The p roxim al part of the torn ligam ent m ay becom e trapp ed between the head of the radius and the capitulum of the hum erus. The source of p ain is the pinched anular ligam ent.

Up p e r Lim b

ELBOW JOINT

139

Bicipital aponeurosis Biceps brachii tendon Brachial artery Lateral cutaneous nerve of forearm Radial nerve

Median nerve

Brachioradialis

Brachialis

Extensor carpi radialis longus

ARM

Pronator teres

Joint capsule of elbow joint

Trochlea

Capitulum

Common flexor tendon Ulnar nerve

Common extensor tendon

Ulnar collateral ligament Antebrachial fascia

Flexor carpi ulnaris

Anconeus Subcutaneous olecranon bursa Olecranon

Synovial fold

Synovial fold

Ulnar nerve Ulnar collateral ligament Coronoid process

Radial collateral ligament Head of radius

FOREARM

Proximal radioulnar joint

Radial nerve

Median nerve Brachial artery

Transverse Section

Humerus ARM

Capitulum Trochlea

Joint plane

FOREARM

Coronoid process of ulna Head of radius

ARTICULAR SURFACES OF ELBOW JOINT

2.58

The tissue surrounding the condyles of the hum erus has been sectioned in a transverse plane, followed by disarticulation of the elbow joint, revealing the articular surfaces. Com p are the forearm (inferior) com ponent with Figure 2.57B. • Synovial folds containing fat overlie the p eriphery of the head of the radius and the nonarticular indentations on the trochlear notch of the ulna. • The radial nerve is in contact with the joint capsule, the ulnar nerve is in contact with the ulnar collateral ligam ent, and the m edian nerve is separated from the joint capsule by the brachialis m uscle.

Up p e r Lim b

140 TABLE 2.11

ANTERIOR FOREARM

ARTERIES OF FOREARM

Radial art e ry Orig in: In cubital fossa, as smaller terminal branch of brachial artery Co urse / Dist ribut io n: Runs distally under brachioradialis, lateral to exor carpi radialis, de ning boundary between the exor and extensor compartments and supplying the radial aspect of both. Gives rise to a super cial palmar branch near the radiocarpal joint; it then transverses the anatomical snuff box to pass between the heads of the rst dorsal interosseous muscle joining the deep branch of the ulnar artery to form the deep palmar arch Ulnar art e ry

Profunda brachii artery (deep artery of arm) Superior ulnar collateral artery Inferior ulnar collateral artery Radial collateral artery Middle collateral artery Brachial artery (in cubital fossa) Interosseous recurrent artery Radial recurrent artery

Orig in: In cubital fossa, as larger terminal branch of brachial artery

Anterior ulnar recurrent artery

Co urse / Dist ribut io n: Passes distally between second and third layers of forearm exor muscles, supplying ulnar aspect of exor compartment; passes super cial to exor retinaculum at wrist, continuing as the super cial palmar arch (with super cial branch of radial) after its deep palmar branch joins the deep palmar arch

Posterior ulnar recurrent artry

Radial re curre nt art e ry Orig in: In cubital fossa, as rst (lateral) branch of radial artery Co urse / Dist ribut io n: Courses proximally, super cial to supinator, passing between brachioradialis and brachialis to anastomose with radial collateral artery

Common interosseous artery Anterior interosseous artery

Ant e rio r and po st e rio r ulnar re curre nt art e rie s Orig in: In and immediately distal to cubital fossa, as rst and second medial branches of ulnar artery Co urse / Dist ribut io n: Course proximally to anastomose with the inferior and superior ulnar collateral arteries, respectively, forming collateral pathways anterior and posterior to the medial epicondyle of the humerus Co m m o n int e ro sse o us art e ry

Posterior interosseous artery

Radial artery Ulnar artery

Orig in: Immediately distal to the cubital fossa, as rst lateral branch of ulnar artery Co urse / Dist ribut io n: Terminates almost immediately, dividing into anterior and posterior interosseous arteries Ant e rio r and po st e rio r int e ro sse o us art e rie s Orig in: Distal to radial tubercle, as terminal branches of common interosseous Co urse / Dist ribut io n: Pass to opposite sides of interosseous membrane; anterior artery runs on interosseous membrane; posterior artery runs between super cial and deep layers of extensor muscles as primary artery of compartment Int e ro sse o us re curre nt art e ry

Deep palmar arch Superficial palmar arch

Orig in: Initial part of posterior interosseous artery Co urse / Dist ribut io n: Courses proximally between lateral epicondyle and olecranon, deep to anconeus, to anastomose with middle collateral artery

Anterior View

2.59

ARTERIES OF FOREARM

ANTERIOR FOREARM

Inferior ulnar collateral artery

Trochlear notch Coronoid process

Ulnar artery

141

Olecranon

Brachial artery

Radial recurrent artery

Up p e r Lim b

Anular ligament of radius

Posterior subcutaneous surface of olecranon Tubercle for ulnar collateral ligament Tuberosity of ulna

Radial artery

Tuberosity of radius Ulnar recurrent artery

Common Anterior

Posterior interosseous artery

Common interosseous artery

Anterior oblique line

Anterior interosseous artery

Interosseous arteries

Posterior

Posterior border Ulnar artery

Medial surface Anterior border

Anterior border Anterior surface

Anterior surface Interosseous border

Interosseous border Interosseous membrane

Radial artery

Pronator crest

Triangular area Distal radio-ulnar joint Superficial palmar branch of radial artery

Styloid process

Head of ulna Styloid process Articular disc

B. Anterior View Radial artery

ARTERIES OF FOREARM AND LIGAMENTS OF RADIO-ULNAR JOINTS

Deep palmar arch Superficial palmar arch

A. Anteroposterior View

2.60

A. Brachial arteriogram . B. Radio-ulnar ligam ents and interosseous arteries. The ligam ent m aintaining the proxim al radioulnar joint is the anular ligam ent, that for the distal joint is the articular disc, and that for the m iddle joint is the interosseous m em brane. The interosseous m em brane is attached to the interosseous borders of the radius and ulna, but it also sp reads onto their surfaces.

Up p e r Lim b

142

ANTERIOR FOREARM

Lateral supra-epicondylar ridge

Brachioradialis

Medial supra-epicondylar ridge

Extensor carpi radialis longus

Lateral epicondyle

Medial epicondyle

Capitulum Head of radius

Pronator teres

Common extensor origin

Trochlea

Common flexor origin

Coronoid process

Flexor digitorum superficialis

Tuberosity of ulna

Tuberosity of radius

Biceps brachii Supinator

Brachialis Pronator teres, ulnar head

Flexor digitorum superficialis

Anterior oblique line Pronator tuberosity

Pronator teres Ulna

Flexor pollicis longus

Radius

Flexor digitorum profundus

Pronator crest Pronator quadratus Head of ulna Styloid process of radius Scaphoid Trapezium Trapezoid

1 Proximal phalanx Interphalangeal (IP) joint Distal phalanx Proximal interphalangeal (PIP) joint

2

3

4

5

Flexor carpi ulnaris Abductor pollicis longus Flexor carpi radialis

Metacarpophalangeal (MCP) joint

Middle

Flexor pollicis longus Phalanges

Distal

Distal interphalangeal (DIP) Joint

A

2.61

Brachioradialis

Styloid process of ulna Lunate Triquetrum Pisiform Hamate Capitate Metacarpal bones

Proximal

Flexor digitorum superficialis Anterior View

B

Flexor digitorum profundus

BONES OF FOREARM AND HAND AND ATTACHMENTS OF FOREARM MUSCLES

A. Bony features. B. Sites of m uscle attachm ents.

Pronator quadratus

Extensor carpi ulnaris

Up p e r Lim b

ANTERIOR FOREARM

Common flexor origin on medial epicondyle of humerus Brachioradialis

Pronator teres

Median nerve

Median nerve

Pronator teres

Supinator

Palmaris longus

Flexor digitorum profundus

Flexor carpi ulnaris Flexor carpi radialis

Flexor digitorum superficialis

Flexor retinaculum Pisiform

143

Radius

Flexor pollicis longus Pronator quadratus

Flexor pollicis longus

Ulna

Pronator quadratus Wrist

Distal phalanx of thumb

Palmar aponeurosis

Carpometacarpal

Metacarpophalangeal Proximal interphalangeal Distal interphalangeal

Middle phalanges of fingers 1st layer

Distal phalanges of fingers 2nd layer

3rd layer

4th layer

Anterior Views

2.62

MUSCLES OF ANTERIOR FOREARM The m uscles of the anterior aspect of the forearm are arranged in three layers.

TABLE 2.12

MUSCLES OF ANTERIOR FOREARM

Muscle

Proxima l Atta chment

Dista l Atta chment

Pronator teres

Medial epicondyle of humerus and coronoid process of ulna

Middle of lateral surface of radius (pronator tuberosity)

Flexor carpi radialis

Innerva tion

Ma in Actions

Median nerve (C6–C7 )

Pronates forearm and exes elbow joint

Base of 2nd and 3rd metacarpals

Flexes and abducts wrist joint

Palmaris longus

Medial epicondyle of humerus

Distal half of exor retinaculum and palmar aponeurosis

Median nerve (C7–C8 )

Flexes wrist joint and tightens palmar aponeurosis

Flexor carpi ulnaris

Humeral head: medial epicondyle of humerus Ulnar head: olecranon and posterior border of ulna

Pisiform, hook of hamate, and 5th metacarpal

Ulnar nerve (C7–C8 )

Flexes and adducts wrist joint

Flexor digitorum super cialis

Humero-ulnar head: medial epicondyle of humerus, ulnar collateral ligament, and coronoid process of ulna Radial head: superior half of anterior border of radius

Bodies of middle phalanges of medial four digits

Median nerve (C7, C8 , and T1)

Flexes PIPs of medial four digits; acting more strongly, it exes MCPs and wrist joint

Flexor digitorum profundus

Proximal three quarters of medial and anterior surfaces of ulna and interosseous membrane

Bases of distal phalanges of medial four digits

Medial part: ulnar nerve (C8 –T1) Lateral part: median nerve (C8 –T1)

Flexes DIPs of medial four digits; assists with exion of wrist joint

Flexor pollicis longus

Anterior surface of radius and adjacent interosseous membrane

Base of distal phalanx of thumb

Distal fourth of anterior surface of ulna

Distal fourth of anterior surface of radius

Pronator quadratus

Anterior interosseous nerve from median (C8 –T1)

Flexes IP joints of 1st digit (thumb) and assists exion of wrist joint Pronates forearm; deep bers bind radius and ulna together

Up p e r Lim b

144

ANTERIOR FOREARM

Median nerve

Biceps brachii Brachialis

Common flexor origin Brachioradialis

Brachial artery Medial epicondyle of humerus (common flexor origin)

Pronator teres Musculocutaneous nerve Bicipital aponeurosis (reflected)

Palmaris longus

Flexor carpi radialis

Brachialis

Flexor carpi ulnaris

Pronator teres

Radial artery Flexor carpi radialis

Brachioradialis

Flexor retinaculum

Palmaris longus Palmar aponeurosis

Flexor carpi ulnaris

Radial artery

A. Anterior View Superficial branch of radial nerve

2.63

SUPERFICIAL MUSCLES OF FOREARM AND PALMAR APONEUROSIS

• At the elbow, the brachial artery lies between the biceps tendon and m edian nerve. It then bifurcates into the radial and ulnar arteries. • At the wrist, the radial artery is lateral to the exor carp i radialis tendon, and the ulnar artery is lateral to exor carpi ulnaris tendon. • In the forearm , the radial artery lies between the exor and extensor com partm ents. The m uscles lateral to the artery are supplied by the radial nerve, and those m edial to it by the m edian and ulnar nerves; thus, no m otor nerve crosses the radial artery. • The b rachioradialis m uscle slightly overlap s the radial artery, which is otherwise sup er cial. • The four sup er cial m uscles all attach proxim ally to the m edial epicondyle of the hum erus (com m on exor origin). • The palm aris longus m uscle, in this specim en, has an anom alous distal belly; this m uscle usually has a sm all belly at the com m on exor origin and a long tendon that is continued into the p alm as the palm ar aponeurosis. The palm aris longus is absent unilaterally or bilaterally in approxim ately 14% of lim bs.

Flexor pollicis longus

Flexor digitorum superficialis

Flexor carpi radialis Palmaris longus

Abductor pollicis longus Superficial palmar branch of radial artery

Median nerve Flexor carpi ulnaris Ulnar artery Ulnar nerve Palmaris brevis

Palmar aponeurosis

Palmar digital arteries and nerves Superficial transverse metacarpal ligament

B. Anterior View

ANTERIOR FOREARM

Up p e r Lim b Ulnar nerve

Biceps brachii

Triceps brachii

Median nerve

Reflected:

Brachial artery Median nerve

145

Pronator teres

Brachioradialis

Flexor carpi radialis Radial nerve: Superficial branch

Supinator Pronator teres

Brachialis

Deep branch Radial recurrent artery

Flexor digitorum superficialis, humero-ulnar head

Ulnar artery

Flexor digitorum superficialis

Nerve to: Flexor carpi ulnaris Flexor digitorum profundus

Supinator Flexor pollicis longus

Pronator quadratus Flexor carpi ulnaris

Pronator teres

Radial artery

Flexor digitorum profundus Ulnar nerve Ulnar artery

A. Anterior View

Flexor digitorum superficialis, radial head

Flexor digitorum superficialis

Flexor pollicis longus Pronator quadratus Dorsal (cutaneous) branch of ulnar nerve

Pronator quadratus

Dorsal carpal branch of ulnar artery Flexor digitorum superficialis Flexor digitorum profundus

Palmar carpal branch of radial artery Superficial palmar branch of radial artery

Persisting median artery Median nerve

Flexor carpi radialis (reflected)

Palmaris longus (reflected)

B. Anterior View

FLEXOR DIGITORUM SUPERFICIALIS AND RELATED STRUCTURES • The exor digitorum super cialis m uscle is attached p roxim ally to the hum erus, ulna, and radius. • The ulnar artery passes obliq uely posterior to the exor digitorum sup er cialis; at the m ed ial border of the m uscle, the ulnar artery joins the ulnar nerve.

2.64

• The m edian nerve descends vertically posterior to the exor digitorum super cialis and appears distally at its lateral border. • The m edian artery of this specim en is a variation resulting from persistence of an em bryologic vessel that usually disapp ears.

Up p e r Lim b

146

ANTERIOR FOREARM

Musculocutaneous nerve Brachialis Medial epicondyle of humerus

Brachioradialis

Brachial artery Median nerve

Radial nerve

Median nerve

Superficial branch

Flexor digitorum superficialis (humeroulnar head)

Deep branch

Biceps brachii tendon

Extensor carpi radialis longus Flexor digitorum profundus

Anterior interosseous nerve

Extensor carpi radialis brevis

Posterior ulnar recurrent artery

Supinator

Anterior interosseous artery

Flexor pollicis longus

Flexor carpi ulnaris

Pronator teres (cut) Pronator quadratus

Ulnar artery Ulnar nerve

Flexor digitorum superficialis (radial head, cut)

3rd, 4th, Flexor 5th digits digitorum profundus muscle 2nd digit belly for

Flexor pollicis longus

Radial artery

A. Anterior View Pronator quadratus

Palmar radiocarpal ligament Flexor retinaculum (transverse carpal ligament) Opponens pollicis Flexor pollicis brevis

2.65

DEEP FLEXORS OF DIGITS AND RELATED STRUCTURES

• The ulnar nerve enters the forearm posterior to the m edial epicondyle, then descends between the exor digitorum p rofundus and exor carpi ulnaris, and is joined by the ulnar artery. At the wrist, the ulnar nerve and artery pass anterior to the exor retinaculum and lateral to the pisiform to enter the palm . • At the elbow, the ulnar nerve supp lies the exor carpi ulnaris and the m edial half of the exor digitorum profundus m uscles; proxim al to the wrist, it gives off the dorsal (cutaneous) branch. • The four lum b ricals arise from the exor digitorum profundus tendons.

Abductor pollicis brevis

Dorsal (cutaneous) branch of ulnar nerve Dorsal carpal branch of ulnar artery Pisiform Median nerve Deep branch of ulnar nerve and artery Opponens digiti minimi Abductor digiti minimi

4th lumbrical

1st lumbrical 2nd lumbrical

B. Anterior View

3rd lumbrical

Up p e r Lim b

ANTERIOR FOREARM

147

Layer of fat Ulnar nerve

Radial nerve

Median nerve

Medial epicondyle of humerus

Brachialis

Anterior interosseous nerve

Ulnar nerve

Radial nerve:

Radius

Deep branch

Ulna

Tendon of biceps brachii

Superficial branch

Subtendinous bursa of biceps Anterior interosseous nerve

Supinator

Pronator quadratus

Common interosseous artery

Median nerve

Anterior interosseous nerve

Anterior oblique line of radius

Anterior interosseous artery Flexor digitorum profundus Pronator teres (distal attachment)

Flexor carpi ulnaris

A. Anterior View Flexor pollicis longus

Tendon of brachioradialis Pronator quadratus Radial artery Abductor pollicis longus Flexor retinaculum (transverse carpal ligament) Opponens pollicis

2nd digit 3rd digit 4th digit 5th digit

Tendons of flexor digitorum profundus

Median nerve Pisiform bone Ulnar nerve and artery Abductor digiti minimi

Opponens digiti minimi

B. Anterior View

DEEP FLEXORS OF DIGITS AND SUPINATOR • The anterior interosseous nerve and artery pass deep ly between the exor pollicis longus and exor digitorum profundus m uscles to lie on the interosseous m em brane. • The deep branch of the radial nerve p ierces and innervates the sup inator m uscle.

2.66 Se ve ran ce o f t h e d e e p b ran ch o f t h e rad ial n e rve results in an inability to extend the thum b and MCP joints of the other digits. Loss of sensation does not occur because the deep branch is entirely m uscular and articular in distribution.

148

Up p e r Lim b

ANTERIOR WRIST AND PALM OF HAND

2

1

3

LATERAL

MEDIAL

5

1 4

A

Recurrent branch of median nerve Flexor retinaculum (transverse carpal ligament)

Hypothenar muscles Hook of hamate Palmar branches of ulnar nerve and ulnar artery

Thenar muscles

Pisohamate ligament

MEDIAL

Trapezium

Deep branches of ulnar artery and nerve arising in ulnar (Guyon) canal

LATERAL Palmar carpal ligament (cut)

Pisiform (2) Palmar carpal ligament (cut) Palmaris longus tendon (1)

Palmar cutaneous branch of median nerve

Flexor digitorum superficialis (5)

Radial artery Median nerve

Flexor carpi ulnaris (3)

Flexor carpi radialis (4)

B Anterior Views of Right Hand and Wrist

2.67

STRUCTURES OF ANTERIOR WRIST

A. Surface anatom y. B. Schem atic illustration. C. Dissection. • The distal skin incision follows the transverse skin crease at the wrist. The incision crosses the pisiform , to which the exor carpi ulnaris m uscle attaches, and the tubercle of the scaphoid, to which the tendon of exor carpi radialis m uscle is a guide. • The p alm aris longus tendon bisects the transverse skin crease; deep to the lateral m argin of the tendon is the m edian nerve. • Note the ulnar (Guyon) canal through which the ulnar vessels and nerve pass m edial to the pisiform .

• The radial artery passes deep to the tendon of the abductor pollicis longus m uscle. • The exor digitorum super cialis tendons to the 3rd and 4th digits becom e anterior to those of the 2nd and 5th digits. • The recurrent branch of the m edian nerve to the thenar m uscles lies within a circle whose center is 2.5 to 4 cm distal to the tubercle of the scaphoid.

ANTERIOR WRIST AND PALM OF HAND

Up p e r Lim b

MEDIAL

149

LATERAL

Recurrent branch of median nerve to thenar muscles

Pisiform Palmaris longus tendon Flexor carpi ulnaris Ulnar nerve Ulnar artery Dorsal branch of ulnar nerve 3rd digit Flexor digitorum superficialis tendons to:

2nd digit 4th digit 5th digit

Tubercle of scaphoid Superficial palmar branch of radial artery Abductor pollicis longus tendon Palmar branch of median nerve Median nerve Palmar carpal branch of radial artery Flexor pollicis longus Superficial branch of radial nerve Radial artery Brachioradialis

Palmaris longus

C. Anterior View

STRUCTURES OF ANTERIOR WRIST (continued ) Le sio n s o f t h e m e d ian n e rve usually occur in two p laces: the forearm and wrist. The m ost com m on site is where the nerve passes though the carpal tunnel. Lacerations of the wrist often cause m edian nerve injury because this nerve is relatively close to the surface. This results in paralysis of the thenar m uscles and the rst two lum bricals. Hence, opposition of the thum b is not possible and ne control m ovem ents of the 2nd and 3rd digits are im paired. Sensation is also lost over the thum b and adjacent two and a half digits.

2.67 Median nerve injury resulting from a perforating wound in the elbow region results in loss of exion of the proxim al and distal interphalangeal joints of the 2nd and 3rd digits. The ability to ex the m etacarpop halangeal joints of these dig its is also affected because digital branches of the m edian nerve supply the 1st and 2nd lum bricals. The p alm ar cutaneous branch of the m edian nerve does not traverse the carpal tunnel. It supplies the skin of the central p alm , which rem ains sensitive in carpal tunnel syndrom e.

Up p e r Lim b

150

Middle (3rd digit) Ring (4th digit)

ANTERIOR WRIST AND PALM OF HAND

Middle (3rd digit)

Index (2nd digit)

Ring (4th digit)

Distal interphalangeal joint (DIP)

Distal

Little (5th digit)

Little (5th digit) Interphalangeal digital creases

Middle

Radial longitudinal crease

Proximal transverse

Palmar creases

Hypothenar eminence

Metacarpophalangeal joint (MCP)

Thumb (1st digit)

Interphalangeal joint crease

Thenar Middle

Proximal interphalangeal joint (PIP)

Thumb (1st digit)

Proximal

Distal transverse

Index (2nd digit)

Carpometacarpal joint of 5th digit (CMC) Interphalangeal joint of thumb (IP)

Metacarpophalangeal joint crease Intercarpal joints

Thenar eminence Distal wrist crease Proximal wrist crease

A

Carpometacarpal joint of thumb (CMC) Midcarpal joint (red line)

B

Distal radio-ulnar joint

Radiocarpal joint (green line)

Anterior Views

2.68

SURFACE ANATOMY OF HAND AND WRIST

A. Skin creases of wrist and hand. B. Surface projection of joints of wrist and hand. Note relationship of b ones and joints to features of the hand. The palm ar skin presents several m ore or less constant exion creases where the skin is rm ly bound to the deep fascia: • Wrist creases: p ro xim al, m id d le , d ist al. The distal wrist crease indicates the proxim al border of the exor retinaculum . • Palmar creases: rad ial lo n g it ud in al cre ase (the “life line” of palm istry), proxim al and distal transverse palm ar creases

• Transverse digital flexion creases: Th e p ro xim a l d ig it a l cre a se is located at th e root of th e d ig it, ap p roxim ately 2 cm d istal to th e m etacarp op h alan g eal join t. Th e p roxim al d ig ital crease o f th e th um b cro sses ob liq u ely, p roxim al to th e 1 st m etacarp op h alan g eal join t. Th e m id d le d ig it a l cre a se lies over th e p ro xim al in terp h alan g eal join t, an d th e d ist a l d ig it a l cre a se lies p roxim al to th e d istal in terp h alan g eal join t. Th e th um b , h avin g two p h alan g es, h as on ly two flexion creases.

Up p e r Lim b

ANTERIOR WRIST AND PALM OF HAND

151

Synovial sheath

Fibrous digital sheath

Anular part (pulley) Cruciate part (pulley) Skin (Grayson) ligament Proper palmar digital artery

Superficial transverse metacarpal ligament

Spiral bands

Proper palmar digital nerve

Digital band

Common palmar digital artery

Distal commissural ligament

Transverse fibers Palmar aponeurosis Longitudinal fibers

Radialis indicis artery Princeps pollicis artery Proximal commissural ligament

Hypothenar fascia

Superficial palmar arch Flexor pollicis brevis

Recurrent branch of median nerve

Abductor pollicis brevis Thenar fascia

Palmaris brevis

Superficial palmar branch

Palmaris longus tendon

Radial artery

A. Anterior View

B. Dupuytren Contracture

PALMAR (DEEP) FASCIA: PALMAR APONEUROSIS, THENAR AND HYPOTHENAR FASCIA A. Anterior view. The palm ar fascia is thin over the thenar and hypothenar em inences but thick centrally, where it form s the palm ar aponeurosis, and in the digits, where it form s the brous digital sheaths. At the distal end (base) of the palm ar aponeurosis, four bundles of digital and spiral bands continue to the bases and brous digital sheaths of digits 2 to 5. B. Du p u yt re n co n t ra ct u re is a d isease of th e p alm ar fascia resultin g in p rog ressive sh orten in g , th icken in g , an d fib rosis

2.69

of th e p alm ar fascia an d p alm ar ap o n eurosis. Th e fib rous d eg en eration of th e lon g itud in al d ig ital b an d s of th e ap on eurosis on th e m ed ial sid e of th e h an d p ulls th e 4th an d 5th fin g ers in to p artial flexion at th e m etacarp op h alan g eal an d p roxim al in terp h alan g eal join ts. Th e con tracture is freq uen tly b ilateral. Treatm en t o f Dup uytren co n tracture usually in vo lves surg ical excision of all fib ro tic p arts o f th e p alm ar fascia to free th e fin g ers.

152

Up p e r Lim b

ANTERIOR WRIST AND PALM OF HAND

Midpalmar space Thenar space

Thenar fascia Palmar aponeurosis Lateral fibrous septum

Medial fibrous septum

B. Anterior View

1

Hypothenar fascia

1st metacarpal

5 5th metacarpal 5 Compartments:

4

3

Thenar space

2

Midpalmar space

Hypothenar

Dorsal fascia (aponeurosis)

Thenar Central Adductor Interosseous

1 5

4 3

2

A. Transverse Section, Inferior View

2.70

SYNOVIAL CAPSULE OF ELBOW JOINT AND ANULAR LIGAMENT

A. Transverse section through the m iddle of the palm showing the fascial com partm ents for the m usculotendinous structures of the hand. B. Potential fascial sp aces of palm . • The p otential m idp alm ar sp ace lies p osterior to the central com partm ent, is bounded m edially by the hypothenar com partm ent, and is related distally to the synovial sheath of the 3rd, 4th, and 5th digits. • The potential thenar space lies posterior to the thenar compartment and is related distally to the synovial sheath of the index nger. • The p otential m idp alm ar and thenar spaces are sep arated by a septum that passes from the palm ar aponeurosis to the 3rd m etacarpal.

Because the p alm ar fascia is thick and strong, swe llin g s re sult in g fro m h an d in fe ct io n s usually ap pear on the dorsum of the hand where the fascia is thinner. The potential fascial spaces of the palm are im portant because they m ay becom e infected. The fascial spaces determ ine the extent and direction of the spread of pus form ed in the infected areas. Depending on the site of infection, pus will accum ulate in the thenar, hypothenar, or adductor com partm ents. Antibiotic therapy has m ade infections that sp read beyond one of these fascial com partm ents rare, but an untreated infection can spread proxim ally through the carpal tunnel into the forearm anterior to the pronator quadratus and its fascia.

Up p e r Lim b

ANTERIOR WRIST AND PALM OF HAND

153

Proper palmar digital artery Proper palmar digital nerve

2nd lumbrical raised from its tunnel

Digital band of palmar aponeurosis Palmar attachments of palmar aponeurosis

First lumbrical 4th lumbrical

Tunnel for long flexor tendons Tunnel for 4th lumbrical

Fascia covering 1st dorsal interosseous Fascia covering adductor pollicis Flexor pollicis brevis (superficial head)

Abductor digiti minimi 4th lumbrical Hypothenar fascia Palmaris brevis

Recurrent branch of median nerve Thenar fascia Palmar aponeurosis Tendon of palmaris longus

Anterior View

PALMAR APONEUROSIS • From the p alm ar aponeurosis, four long itudinal digital band s enter the ngers; the other bers form extensive bro-areolar sep ta that p ass posteriorly to the palm ar lig am ents (see Fig. 2.78) and, m ore proxim ally, to the fascia covering the interossei. Thus, two sets of tunnels exist in the distal half of the palm : (1) tunnels

2.71 for long exor tendons and (2) tunnels for lum bricals, digital vessels, and digital nerves. • In the dissected m iddle nger, note the absence of fat deep to the skin creases of the ngers.

Up p e r Lim b

154

ANTERIOR WRIST AND PALM OF HAND

Flexor digitorum profundus

Flexor digitorum superficialis Lumbricals attached to flexor digitorum profundus tendons

Palmar interossei

1 3

4

Flexor digiti minimi brevis

2

1

3

Abductor digiti minimi

Flexor pollicis brevis

A

Adductor pollicis: Transverse head

Capitate

Abductor pollicis brevis

Flexor retinaculum

2

Oblique head Opponens pollicis

Radius

Ulna

B

Tendon of flexor carpi radialis

Ulna

Anterior View

Anterior View

Flexor digitorum profundus Flexor digitorum superficialis Adductor pollicis (transverse head) P

P

1

2

3

4

Digiti Abductor minimi Flexor brevis

Flexor pollicis longus

D P

D P

2.72

D

Flexor Pollicis brevis Abductor Abductor pollicis longus

Digiti Flexor brevis minimi Abductor Flexor carpi ulnaris

Flexor carpi radialis Adductor pollicis (oblique head)

D Posterior View

D

Opponens pollicis

Extensor carpi ulnaris

C

Adductor pollicis

P

Opponens digiti minimi Dorsal interossei

P

Anterior View

MUSCULAR LAYERS OF PALM

A. Lum bricals. B. Ad ductor pollicis. C. Dorsal (D) and palm ar (P) interossei. D. Bony attachm ents.

Key P = Palmar interossei D = Dorsal interossei

Up p e r Lim b

ANTERIOR WRIST AND PALM OF HAND

Axial line

4

3

2

1

Lumbricals (1–4)

2

3

155

Axial line

1

4

Palmar interossei (Adduction)

3

2

1

Dorsal interossei (Abduction)

Palmar Views

2.73

LUMBRICALS AND INTEROSSEI

Th e lum b ricals an d in terossei are in trin sic m uscles of th e h an d . Th e action s of th e p alm ar (ad d uction ) an d d orsal (ab d uction ) in terossei are sh own with arrows.

TABLE 2.13

MUSCLES OF HAND

Muscle

Proxima l Atta chment

Abductor pollicis brevis

Flexor retinaculum and tubercles of scaphoid and trapezium

Flexor pollicis brevis Opponens pollicis

Flexor retinaculum (transverse carpal ligament) and tubercle of trapezium

Dista l Atta chment Lateral side of base of proximal phalanx of thumb

Recurrent branch of median nerve (C8 and T1)

Flexes thumb

Adducts thumb toward lateral border of palm

Medial side of base of proximal phalanx of thumb

Abductor digiti minimi

Pisiform

Medial side of base of proximal phalanx of digit 5

Lumbricals 1 and 2

Abducts thumb and helps oppose it

Opposes thumb toward center of palm and rotates it medially

Oblique head: bases of 2nd and 3rd metacarpals, capitate, and adjacent carpal bones Transverse head: anterior surface of shaft of 3rd metacarpal

Opponens digiti minimi

Ma in Actions

Lateral side of 1st metacarpal

Adductor pollicis

Flexor digiti minimi brevis

Innerva tion

Deep branch of ulnar nerve (C8 and T1 )

Abducts digit 5, assists in exion of its PIP joint Flexes PIP joint of digit 5

Hook of hamate and exor retinaculum (transverse carpal ligament) Lateral two tendons of exor digitorum profundus

Medial border of 5th metacarpal

Draws 5th metacarpal anteriorly and rotates it, bringing digit 5 into opposition with thumb Median nerve (C8 and T1 )

Lateral sides of extensor expansions of digits 2–5

Lumbricals 3 and 4

Medial three tendons of exor digitorum profundus

Dorsal interossei 1–4

Adjacent sides of two metacarpals

Extensor expansions and bases of proximal phalanges of digits 2–4

Palmar interossei 1–3

Palmar surfaces of 2nd, 4th, and 5th metacarpals

Extensor expansions of digits and bases of proximal phalanges of digits 2, 4, and 5

Flex MCP joints and extend IP joints of digits 2–5

Deep branch of ulnar nerve (C8 and T1 )

Abduct 2–4 MCP joints; act with lumbricals to ex MCP and extend IP joints Adduct 2, 4, and 5 MCP joints; act with lumbricals to ex MCP and extend IP joints

156

Up p e r Lim b

ANTERIOR WRIST AND PALM OF HAND

Arterial network Proper palmar digital nerve Proper palmar digital artery Proper palmar digital nerve

Proper digital nerve 1st lumbrical Fibrous digital sheath

Radialis indicis artery 1st dorsal interosseous

Flexor digitorum superficialis

Common palmar digital nerve

Superficial palmar arch

Adductor pollicis Flexor pollicis brevis superficial head

Abductor digiti minimi Apex of palmar aponeurosis

Recurrent branch of median nerve Abductor pollicis brevis

Palmaris brevis Ulnar nerve Ulnar artery Pisiform

Abductor pollicis longus Palmaris longus Superficial palmar branch of radial artery

Dorsal carpal branch of ulnar artery Dorsal cutaneous branch of ulnar nerve

Radial artery Palmaris longus tendon

Flexor carpi ulnaris

A. Anterior View

2.74

SUPERFICIAL DISSECTION OF PALM, ULNAR, AND MEDIAN NERVES

A. Super cial p alm ar arch and d igital nerves and vessels. • The skin, sup er cial fascia, p alm ar ap oneurosis, and thenar and hyp othenar fasciae have been rem oved. • The sup er cial p alm ar arch is form ed by the ulnar artery and com pleted by the sup er cial palm ar branch of the radial artery. • The four lum bricals lie p osterior to the dig ital vessels and nerves. The lum bricals arise from the lateral sides of the exor digitorum profundus tendons and are inserted into the lateral sid es of the dorsal expansions of the corresp onding digits. The m edial two lum bricals are bipennate and also arise from the m edial sides of adjacent exor digitorum profundus tendons.

• In the digits, a proper palm ar digital artery and nerve lie on each side of the brous d igital sheath. • Note the canal (Guyon) through which the ulnar vessels and nerve pass m edial to the p isiform . Lace rat io n o f p alm ar (art e rial) arch e s. Bleeding is usually profuse when the palm ar (arterial) arches are lacerated. It m ay not be suf cient to ligate (tie off) only one forearm artery when the arches are lacerated because these vessels usually have num erous com m unications in the forearm and hand and thus bleed from both ends.

ANTERIOR WRIST AND PALM OF HAND

Up p e r Lim b

157

Skin ligaments

Proper palmar digital nerve (from ulnar nerve) Skin (Grayson) ligament

Proper palmar digital nerve (from median nerve)

Fibrous digital sheath 2nd lumbrical

Common palmar digital nerve (from ulnar nerve)

1st lumbrical Median nerve (branches to 1st and 2nd lumbricals)

Abductor Digiti minimi Flexor brevis

Adductor pollicis

Opponens

Flexor pollicis brevis (superficial and deep heads)

3rd and 4th lumbricals

Common palmar digital nerves (from median nerve)

Communicating Branches of ulnar nerve

Superficial

Recurrent branch of median nerve Opponens pollicis

Deep Deep branch of ulnar artery Flexor retinaculum (transverse palmar ligament)

Abductor pollicis brevis (cut)

Ulnar nerve Ulnar artery

B. Anterior View

Abductor pollicis longus

SUPERFICIAL DISSECTION OF PALM, ULNAR, AND MEDIAN NERVES (continued ) B. Ulnar and m edian nerves. Carp al t un n e l syn d ro m e results from any lesion that signi cantly reduces the size of the carpal tunnel or, m ore com m only, increases the size of som e of the structures (or their coverings) that pass through it (e.g., in am m ation of the synovial sheaths). The m edian nerve is the m ost vulnerable structure in the carpal tunnel. The m edian nerve has two term inal sensory branches that supp ly the skin of the hand; hence, paresthesia (tingling), hypoesthesia (dim inished sensation), or anesthesia (absence of tactile sensation) m ay occur in the lateral three and a half digits. However, recall that the palm ar cutaneous branch of the m edian nerve arises proxim al

2.74

to and does not pass through the carpal tunnel; thus, sensation in the central palm rem ains unaffected. This nerve also has one term inal m otor branch, the recurrent branch, which innervates the three thenar m uscles. Wasting of the thenar em inence and progressive loss of coordination and strength in the thum b m ay occur. To relieve the com pression, partial or com p lete surgical division of the exor retinaculum , a procedure called carp al t un n e l re le ase , m ay be necessary. The incision is m ade toward the m edial side of the wrist and exor retinaculum to avoid possible injury to the recurrent branch of the m edian nerve. This p rocedure is also d one laparoscopically.

Up p e r Lim b

158

ANTERIOR WRIST AND PALM OF HAND

Key Synovial sheath 3 Osseofibrous tunnel (synovial cavity) Tendon

2 4

Mesotendon (forms vincula)

Synovial Synovial sheath covering of tendon of digit of hand Synovial (2–5 ) lining of tunnel Middle phalanx

5

c

Fibrous digital sheath

Nerve Proper Artery palmar Vein digital

Synovial sheath Tendon

B. Lateral View Tendinous sheath of flexor pollicis longus

Flexor digitorum superficialis and profundus in common flexor sheath

Flexor retinaculum (transverse carpal ligament) Palmaris longus

Palmar Fibrous digital sheath Synovial sheath

Nerve Proper palmar Artery digital Vein

Tendinous sheath of abductor pollicis longus and extensor pollicis brevis

Skin (Grayson) ligament

Flexor carpi radialis

Flexor carpi ulnaris

A. Anterior View

2.75

Tendinous sheath of flexor pollicis longus

Flexor carpi radialis

Flexor digitorum superficialis tendon

Flexor digitorum profundus tendon

Extensor (dorsal) expansion Dorsal

Proximal phalanx C. Transverse Section (level of section indicated in A)

SYNOVIAL SHEATHS OF PALM OF HAND

A. Tendinous (synovial) sheaths of long exor tendons of the digits. B. Osseo brous tunnel and tend inous (synovial) sheath. C. Transverse section through the p roxim al phalanx. Injuries such as puncture of a nger by a rusty nail can cause in fect ion of t h e d ig it al syn ovial sh eat h s. When in am m ation of the tendon and synovial sheath (ten osyn o vitis) occurs, the digit swells and m ovem ent becom es painful. Because the tendons of the 2nd to 4th digits nearly always have separate synovial sheaths, the

infection usually is con ned to the infected digits. If the infection is untreated, the proxim al ends of these sheaths m ay rupture, allowing the infection to spread to the m idpalm ar space. Because the synovial sheath of the little nger is usually continuous with the com m on exor sheath, tenosynovitis in this nger m ay spread to the com m on exor sheath and through the palm and carpal tunnel to the anterior forearm . Likewise, tenosynovitis in the thum b m ay spread through the continuous tendinous sheath of exor pollicis longus.

ANTERIOR WRIST AND PALM OF HAND

Up p e r Lim b

159

Key Synovial sheath Flexor digitorum superficialis (FDS) Flexor digitorum profundus (FDP)

FDS and FDP tendons in digital synovial sheaths 3

Synovial sheath of 5th digit

Palmar ligament (plate)

2

4

5

Anular and cruciform parts of fibrous digital sheath cover digital synovial sheath

Anular (A) part Cruciate (C) part Common flexor sheath (ulnar bursa) 5

5

4 5

4

4

3

3

A5

Distal interphalangeal joint

Anular (A) part

A4 C3

Cruciate (C) part A3

1

C2 Proximal phalanx

2

2

C4

A2

Flexor pollicis longus (FPL) tendon in synovial sheath

C1

3 2

A1 Flexor retinaculum Common synovial sheath of FDS and FDP Flexor carpi radialis tendon FPL tendon

A. Anterior View

FIBROUS DIGITAL SHEATHS A. Fibrous digital and synovial sheaths. B. Anular and cruciate parts (pulleys) of the brous digital sheath. Fib rous d ig ital sh eath s are th e stron g lig am en tous tun n els con tain in g th e exor ten d on s an d th eir syn ovial sh eath s. Th e sh eath s exten d from th e h ead s of th e m etacarp als to th e b ases of th e d istal p h alan g es. Th ese sh eath s p reven t th e ten d on s from

Palmar ligament (plate)

Metacarpal

Flexor digitorum profundus

Synovial sheath Flexor digitorum superficialis

B. Lateral View

2.76 p ullin g away from th e d ig its (b owstrin g in g ). Th e b rous d ig ital sh eath s com b in e with th e b on es to form osseo b rous tun n els th roug h wh ich th e ten d on s p ass to reach th e d ig its. Th e an ular an d cruciform (cruciate) p arts, often referred to clin ically as “p ulleys,” are th icken ed rein forcem en ts of th e b rous d ig ital sh eath s.

160

Up p e r Lim b

ANTERIOR WRIST AND PALM OF HAND

Proper palmar digital arteries Radialis indicis artery Common palmar digital arteries (from superficial palmar arch)

Transverse head Adductor pollicis Oblique head

Palmar metacarpal arteries (from deep palmar arch) Abductor Digiti minimi

Flexor brevis Abductor brevis

Opponens

Flexor brevis Pollicis Opponens

Deep branch of ulnar nerve

Flexor pollicis longus tendon

Deep palmar arch

Flexor retinaculum (cut edge)

Deep branch of ulnar artery

Recurrent branch of deep palmar arch Pisohamate ligament

Trapezium

Deep branch of ulnar nerve Superficial palmar branch Ulnar artery Palmar carpal arch Flexor digitorum profundus (to digits 3–5) 5th digit Flexor digitorum superficialis to

2nd digit 4th digit 3rd digit

Anterior View

2.77

Flexor carpi ulnaris

of radial artery Palmar carpal branch Median nerve Flexor digitorum profundus (to digit 2) Flexor carpi radialis Radial artery Palmaris longus

DEEP DISSECTION OF PALM

• The d eep branch of the ulnar artery joins the radial artery to form the deep p alm ar arch. • The pisoham ate ligam ent is often considered a continuation of the tendon of exor carpi ulnaris, m aking the pisiform a sesam oid bone. Co m p re ssio n o f t h e u ln a r n e r ve m ay occur at th e wrist wh ere it p asses b etween th e p isifo rm an d th e h o o k o f h am ate. Th e

d ep ression b etween th ese b on es is con verted b y th e p isoh am ate lig am en t in to an osseofib rous uln ar can al. Uln a r ca n a l syn d ro m e is m an ifested b y h yp oesth esia in th e m ed ial on e an d on e h alf d ig its an d weakn ess of th e in trin sic h an d m uscles. Clawin g o f th e 4 th an d 5 th d ig its m ay o ccur, b ut in con trast to p ro xim al n erve in ju ry, th eir ab ility to flex th e wrist jo in t is un affected .

Up p e r Lim b

ANTERIOR WRIST AND PALM OF HAND

161

Flexor digitorum profundus

Palmar ligament (plate) Fibrous digital sheath Palmar ligament (plate) Flexor digitorum profundus

Fibrous digital sheath

Flexor digitorum superficialis (split tendon)

*

* Deep transverse metacarpal ligament

Attachment of palmar aponeurosis to palmar ligament

*

*

Palmar ligament (plate)

D1

D2 D3

Twig to joint

P1

Collateral ligament

D4

Twig to 4th lumbrical

P3

P 2

Radial artery Three perforating branches of deep palmar arch

Deep branch of ulnar nerve Hook of hamate Ligaments

Pisometacarpal Pisohamate Pisiform

Articular capsule of carpometacarpal joint of thumb Tubercle of trapezium Flexor retinaculum (transverse palmar ligament) Median nerve Palmar radiocarpal ligament

Ulnar nerve Flexor carpi ulnaris Pronator quadratus

Superficial branch of ulnar nerve Flexor carpi radialis Abductor pollicis longus Brachioradialis

Anterior View

DEEP DISSECTION OF PALM AND DIGITS WITH DEEP BRANCH OF ULNAR NERVE • Three unip ennate palm ar (P1–P3) and four bipennate dorsal (D1–D4) interosseous m uscles are illustrated; the p alm ar interossei adduct the ngers, and the dorsal interossei abduct the ngers in relation to the axial line, an im aginary line through the long axis of the 3rd digit (see Table 2.13).

2.78

• The deep transverse m etacarpal ligam ents unite the palm ar ligam ents; the lum bricals pass anterior to the deep transverse m etacarpal ligam ent, and the interossei pass posterior to the ligam ent. • The pisoham ate and pisom etacarpal ligam ents form the distal attachm ent of exor carpi ulnaris.

Up p e r Lim b

162

ANTERIOR WRIST AND PALM OF HAND

Body of nail

Dorsalis pollicis artery

Lunule

Distal phalanx

Dorsal branch of proper palmar digital artery Skin ligaments

Common palmar digital artery

Proper palmar digital nerve

Superficial palmar arch

Princeps pollicis artery

Palmar metacarpal artery

Proper palmar digital artery

Lateral band of extensor expansion Dorsal digital artery

Subcutaneous tissue

Deep branch of ulnar nerve

Dorsal digital branch of radial nerve Deep palmar arch

Deep branch of ulnar artery Ulnar nerve Ulnar artery

A. Anterior View

2.79

Middle phalanx

Radial artery, palmar branch

Extensor (dorsal) expansion Common palmar digital nerve

Palmar cutaneous branch of median nerve

Common palmar digital artery

Dorsal metacarpal artery Metacarpal

B. Lateral View

ARTERIAL SUPPLY OF HAND

A. Dissection of palm ar arterial arches. B. Digital vessels and nerves. C. Arteriogram of the hand. Note that the super cial palm ar arch is usually com pleted by the super cial palm ar branch of the radial artery, but in this specim en, the d orsalis pollicis artery com pletes the arch. The sup e r cial an d d e e p p alm ar (art e rial) arch e s are not palpable, but their surface m arkings are visible. The super cial p alm ar arch occurs at the level of the distal border of the fully extended thum b. The deep palm ar arch lies approxim ately 1 cm proxim al to the super cial palm ar arch. The location of these arches should be borne in m ind in wounds of the palm and when palm ar incisions are m ade. Interm ittent bilateral attacks of isch e m ia o f t h e d ig it s, m arked b y cyanosis and often accom panied by paresthesia and pain, are characteristically brought on by cold and em otional stim uli. The condition m ay result from an anatom ical abnorm ality or an underlying disease. When the cause of the condition is idiop athic (unknown) or prim ary, it is called Rayn aud syn d ro m e (disease). Since arteries receive innervation from postsynaptic bers from the sym pathetic ganglia, it m ay be necessary to perform a cervicodorsal p resynap tic sym pathectom y to dilate the digital arteries.

Proper palmar digital artery

Princeps pollicis artery

Common palmar digital artery

1st metacarpal

Superficial palmar arch

Deep palmar arch

5th metacarpal Deep palmar branch of ulnar artery Ulnar artery

Radial artery

Radius

C. Anteroposterior View

Up p e r Lim b

ANTERIOR WRIST AND PALM OF HAND

Dorsal branches of proper palmar digital arteries

Proper palmar digital artery gives rise to a dorsal branch

Radialis indicis

Common palmar digital arteries

Dorsal digital arteries

Superficial palmar arch

Dorsal metacarpal arteries

Palmar metacarpal arteries

Perforating branches Dorsal carpal arch

Deep palmar arch

Princeps pollicis

Dorsal carpal branch of ulnar artery

Dorsalis pollicis Palmar carpal arch

Dorsal carpal branch Superficial palmar branch

Anterior interosseous artery

Ulnar artery Anterior interosseous artery

163

Dorsalis indicis

Dorsalis pollicis Princeps pollicis Dorsal carpal arch Radial artery

Posterior interosseus artery

Radial artery Radius Anterior View (Palmar Aspect)

Lateral View (Isolated Third Digit)

Posterior View (Dorsum of Hand)

2.80

ARTERIAL OF SUPPLY HAND

Since hand is placed and held in m any different positions, it requires an abundance of highly branched and anastom osing arteries so that oxygenated b lood is available in all positions.

TABLE 2.14

ARTERIES OF HAND

Artery

Origin

Course

Super cial palmar arch

Direct continuation of ulnar artery; arch is completed on lateral side by super cial branch of radial artery or another of its branches

Curves laterally deep to palmar aponeurosis and super cial to long exor tendons; curve of arch lies across palm at level of distal border of extended thumb

Deep palmar arch

Direct continuation of radial artery; arch is completed on medial side by deep branch of ulnar artery

Curves medially, deep to long exor tendons and is in contact with bases of metacarpals

Common palmar digital

Super cial palmar arch

Pass directly on lumbricals to webbings of digits

Proper palmar digital

Common palmar digital arteries

Run along sides of digits 2–5

Princeps pollicis

Radial artery as it turns into palm

Descends on palmar aspect of 1st metacarpal and divides at the base of proximal phalanx into two branches that run along sides of thumb

Radialis indicis

Radial artery but may arise from princeps pollicis artery

Passes along lateral side of index nger to its distal end

Dorsal carpal arch

Radial and ulnar arteries

Arches within fascia on dorsum of hand

Up p e r Lim b

164

POSTERIOR FOREARM

For subtendinous bursa of triceps brachii Common extensor origin

Lateral epicondyle Medial epicondyle Head of radius

Olecranon

Anconeus

Triceps brachii Flexor carpi ulnaris

Posterior oblique line

Supinator

Flexor digitorum profundus

Posterior border Pronator tuberosity

Extensor pollicis longus

Abductor pollicis longus

Radius

Ulna

Extensor indicis Head of ulna Styloid process of ulna Lunate Triquetrum Hamate Capitate Metacarpal bones

Dorsal tubercle of radius

Scaphoid Trapezium Trapezoid 1 4

3

2

(1st) Proximal Phalanges

Extensor pollicis brevis Brachioradialis Extensor carpi radialis brevis

Styloid process of radius

5

Pronator teres

Extensor carpi ulnaris

Extensor carpi radialis longus Extensor pollicis brevis

Proximal phalanx Extensor pollicis longus

Distal phalanx

(2nd) Middle (3rd) Distal

Extensor (dorsal) expansion

Posterior View

A

2.81

BONES AND MUSCLE ATTACHMENTS ON POSTERIOR FOREARM AND HAND

Abduction

2.82

B

Adduction

Extension

Flexion

Opposition

Reposition

MOVEMENTS OF THUMB

The thum b is rotated 90 degrees com pared to the other dig its. Abduction and adduction at the MCP joint occur in a sagittal

plane; exion and extension at the MCP and IP joints occur in frontal p lanes, op posite to these m ovem ents at other joints.

POSTERIOR FOREARM

Brachioradialis

Extensor carpi radialis longus

Up p e r Lim b

165

Abductor pollicis Extensor longus pollicis brevis

Extensor carpi radialis brevis

A Anconeus

Extensor digitorum

Extensor digiti minimi

Extensor retinaculum

Extensor carpi ulnaris

Extensor pollicis brevis

B Posterior Views

Supinator

Abductor pollicis longus

Extensor pollicis longus

Extensor indicis

2.83

MUSCLES OF POSTERIOR FOREARM A. Super cial. B. Deep .

TABLE 2.15

MUSCLES OF POSTERIOR SURFACE OF FOREARM

Muscle

Proxima l Atta chment

Dista l Atta chment

Innerva tion

Ma in Actions

Brachioradialis

Proximal two thirds of lateral supraepicondylar ridge of humerus

Lateral surface of distal end of radius

Radial nerve (C5, C6 , and C7)

Flexes elbow joint

Extensor carpi radialis longus

Lateral supra-epicondylar ridge of humerus

Base of 2nd metacarpal bone

Radial nerve (C6 and C7)

Base of 3rd metacarpal bone

Deep branch of radial nerve (C7 and C8)

Extensor carpi radialis brevis Extensor digitorum

Lateral epicondyle of humerus

Extensor digiti minimi

Extensor expansions of medial four digits Extensor expansion of 5th digit

Extend and abduct wrist joint Extends medial four metacarpophalangeal joints; extends wrist joint

Posterior interosseous nerve (C7 and C8), a branch of the radial nerve

Extends MCP and IP joints of 5th digit; extends wrist joint

Extensor carpi ulnaris

Lateral epicondyle of humerus and posterior border of ulna

Base of 5th metacarpal bone

Extends and adducts wrist joint

Anconeus

Lateral epicondyle of humerus

Lateral surface of olecranon and superior part of posterior surface of ulna

Supinator

Lateral epicondyle of humerus, radial collateral and anular ligaments, supinator fossa, and crest of ulna

Lateral, posterior, and anterior Deep branch of radial surfaces of proximal third of radius nerve (C5 and C6 )

Supinates forearm

Abductor pollicis longus

Posterior surface of ulna, radius, and interosseous membrane

Base of 1st metacarpal bone

Abducts and extends carpometacarpal joint of thumb

Extensor pollicis brevis

Posterior surface of radius and interosseous membrane

Base of proximal phalanx of thumb

Extends MCP joint of thumb; extends wrist joint

Extensor pollicis longus

Posterior surface of middle third of ulna and interosseous membrane

Base of distal phalanx of thumb

Extensor indicis

Posterior surface of ulna and interosseous membrane

Extensor expansion of 2nd digit

Radial nerve (C7, C8, and T1)

Posterior interosseous nerve (C7 and C8 )

Assists triceps brachii in extending elbow joint; stabilizes elbow joint; abducts ulna during pronation

Extends MCP and IP joints of thumb; extends wrist joint Extends MCP and IP joints of 2nd digit; extends wrist joint

Up p e r Lim b

166

POSTERIOR FOREARM

Anconeus and its nerve

Deep branch of radial nerve

Anconeus Lateral muscles: Brachioradialis

Brachioradialis

Supinator

Extensor carpi radialis longus Extensor carpi radialis brevis

Posterior interosseous recurrent artery

Extensor carpi radialis longus Extensor carpi radialis brevis Posterior interosseous nerve

Extensor digitorum

Extensor carpi ulnaris Extensor digiti minimi Extensor indicis

Extensor retinaculum Dorsal carpal branch of ulnar artery Extensor carpi radialis brevis Dorsal carpal arch Perforating arteries Dorsal metacarpal arteries

Dorsal digital arteries

Posterior interosseous artery

Extensor digitorum

Pronator teres

Extensor digiti minimi Extensor carpi ulnaris

Outcropping muscles of thumb: Abductor pollicis longus Extensor pollicis brevis

Abductor pollicis longus

Extensor pollicis longus

Extensor pollicis brevis

Extensor indicis

Extensor pollicis longus Extensor pollicis longus

Extensor retinaculum

Radial artery in the anatomical snuff box

Extensor carpi radialis: Brevis Longus

Dorsal carpal branch of radial artery Extensor carpi radialis longus Dorsalis pollicis arteries

Extensor pollicis longus Dorsalis indicis artery 1st dorsal interosseous Radialis indicis artery

Dorsalis indicis artery 1st dorsal interosseous 2nd dorsal interosseous

Radial artery (in “snuff box”) Extensor pollicis brevis Dorsalis pollicis arteries

1st dorsal interosseous

A. Posterior View

B. Posterolateral View

2.84

EXTENSOR MUSCLES OF FOREARM

A. Super cial dissection. B. Deep dissection.

Adductor pollicis

POSTERIOR WRIST AND DORSUM OF HAND

Up p e r Lim b

167

Palmar branch of median nerve Dorsal View

B

Anterior View

Key Median nerve Ulnar nerve Radial nerve

A

Lateral cutaneous nerve of forearm (musculocutaneous nerve) Dual innervation by lateral cutaneous nerve of forearm and radial nerve

Posterior cutaneous nerve of forearm (from radial nerve)

C. Dorsal Views

CUTANEOUS INNERVATION OF HAND A. Dissection of nerves of dorsum of hand. B. Distribution of the cutaneous nerves to the palm and dorsum of the hand, schem atic

2.85 illustration. C. Variations in pattern of cutaneous nerves in dorsum of hand.

168

Up p e r Lim b

POSTERIOR WRIST AND DORSUM OF HAND

Interphalangeal joint of thumb

Proximal interphalangeal joint

Dorsal venous network of hand

Metacarpophalangeal joint of thumb

1st dorsal interosseous

Metacarpophalangeal joint

Extensor pollicis brevis Extensor pollicis longus Tendons of extensor digitorum Anatomical snuff box

Head of ulna

A. Dorsal View

2.86

DORSUM OF HAND

A. Surface anatom y. The interphalangeal joints are exed, and the m etacarpophalangeal joints are hyperextended to dem onstrate the extensor digitorum tendons. B. Tendinous (synovial) sheaths distended with blue uid. C. Transverse section of distal forearm . Num bers refer to structures ( B) . D. Sites of bony attachm ents. • Six tendinous sheaths occup y the six osseo brous tunnels deep to the extensor retinaculum . They contain nine tendons: tendons for the thum b in sheaths 1 and 3, tendons for the extensors of the wrist in sheaths 2 and 6, and tendons for the extensors of the wrist and ngers in sheaths 4 and 5.

• The tendon of the extensor pollicis longus hooks around the dorsal tubercle of radius to pass obliquely across the tendons of the extensor carpi radialis longus and brevis to the thum b. The tendons of the abductor pollicis longus and extensor pollicis brevis are in the sam e tendinous sheath on the dorsum of the wrist. Excessive friction of these tend ons results in brous thickening of the sheath and stenosis of the osseo brous tunnel, Que rvain t e n o vag in it is st e n o san s. This condition causes p ain in the wrist that radiates proxim ally to the forearm and distally to the thum b.

POSTERIOR WRIST AND DORSUM OF HAND

Up p e r Lim b

169

Extensor (dorsal) expansion Intertendinous connection

4th dorsal interosseous 1st dorsal interosseous

Extensor digiti minimi (5) Extensor carpi ulnaris (6) Extensor digitorum (4) Extensor indicis (4)

Extensor carpi Longus radialis (2) Brevis Extensor pollicis longus (3)

Extensor retinaculum Abductor pollicis longus (1) Extensor pollicis brevis (1) Dorsal tubercle of radius deep to extensor retinaculum Extensor expansion

B. Dorsal View

Dorsal interossei 2nd dorsal interosseous

Extensor retinaculum Dorsal tubercle of radius 3 2

Extensor pollicis longus 4

5

6

1

Extensor pollicis brevis 1st dorsal interosseous Extensor carpi radialis longus Extensor carpi radialis brevis

C. Transverse Section

Radius

Ulna

D. Posterior (Dorsal) View

3rd dorsal interosseous 4th dorsal interosseous Extensor carpi ulnaris

170

Up p e r Lim b

POSTERIOR WRIST AND DORSUM OF HAND

Extensor expansion

Extensor indicis

Dorsal digital vein

Body of 2nd metacarpal

* *

1st dorsal interosseous

* Extensor digiti minimi

Intertendinous connections *

Radial artery Extensor carpi radialis longus

Dorsal branch of ulnar nerve

Extensor carpi radialis brevis Extensor retinaculum Superficial branch of radial nerve

Extensor pollicis longus Extensor pollicis brevis Abductor pollicis longus

Extensor carpi ulnaris Extensor indicis Extensor digiti minimi Extensor digitorum

E. Dorsal View

2.86

DORSUM OF HAND (continued )

E. Tendons on dorsum of hand and extensor retinaculum . • The d eep fascia is thickened to form the extensor retinaculum . • Proxim al to the knuckles, intertendinous connections extend between the tendons of the digital extensors and, thereby, restrict the independent action of the ngers. Gan g lion cyst . Som etim es a nontender cystic swelling appears on the hand, m ost com m only on the dorsum of the wrist. The thin-walled

cyst contains clear m ucinous uid. Clinically, this type of swelling is called a ganglion (a swelling or knot). These synovial cysts are close to and often com m unicate with the synovial sheaths. The distal attachm ent of the extensor carpi radialis brevis tendon is a com m on site for such a cyst.

Up p e r Lim b

POSTERIOR WRIST AND DORSUM OF HAND

171

Distal phalanx

Distal phalanx Terminal tendon

Middle phalanx Lateral bands

Vincula brevia

Synovial membrane Central (median) band

Central (median) band

Vincula longa

Extensor expansion

Extensor expansion Flexor digitorum superficialis

Lateral band Extensor expansion anchored to palmar ligament

2nd lumbrical

2nd lumbrical 3rd dorsal interosseous

2nd dorsal interosseous 2nd dorsal interosseous

Extensor digitorum

Flexor digitorum profundus

A. Dorsal View

Extensor digitorum

3rd metacarpal

B. Lateral View Extensor digitorum

Proximal interphalangeal joint Extensor expansion

Dorsal hood of extensor expansion Middle phalanx

Distal interphalangeal joint

Fibrous digital sheath

Median band

Distal phalanx

C. Lateral View

Fibrous digital sheath

Retinacular ligament

Retinacular ligament

Oblique Lateral band Transverse

D. Lateral View

EXTENSOR (DORSAL) EXPANSION OF THIRD DIGIT A. Dorsal view. B. Lateral view. C. Retinacular ligam ents of extended dig it. D. Retinacular ligam ents of exed dig it. • The hood covering the head of the m etacarpal is attached to the palm ar ligam ent. • Contraction of the m uscles attaching to the lateral band will produce exion of the m etacarpophalangeal joint and extension of the interphalang eal joints.

2.87 • The retinacular ligam ent is a brous band that runs from the proxim al phalanx and brous digital sheath obliquely across the m iddle p halanx and two interphalangeal joints to join the extensor (dorsal) expansion and then to the distal phalanx. • On exion of the distal interphalangeal joint, the retinacular ligam ent becom es taut and pulls the proxim al joint into exion; on extension of the proxim al joint, the distal joint is pulled by the ligam ent into nearly com plete extension.

Up p e r Lim b

172

LATERAL WRIST AND HAND

Adductor pollicis 1st dorsal interosseous

Dorsalis indicis artery Perforating vein Dorsalis pollicis artery

Subtendinous bursa of extensor carpi radialis brevis

Radial artery in snuff box

Extensor carpi radialis brevis Dorsal carpal branch

Cephalic vein of forearm Abductor pollicis longus Extensor pollicis brevis

Extensor pollicis longus Extensor carpi radialis longus

Tributaries of cephalic vein of forearm

Radial nerve, superficial branch

A

2.88

Lateral Views

B

LATERAL WRIST AND HAND

A. Anatom ical snuff box—I. • The depression at the base of the thum b, the “anatom ical snuff box,” retains its nam e from an archaic habit. • Note the sup er cial veins, including the cephalic vein of forearm and/ or its tributaries, and cutaneous nerves crossing the snuff box.

B. Anatom ical snuff box—II. • Three long tendons of the thum b form the boundaries of the snuff box; the extensor p ollicis longus form s the m edial boundary and the abductor pollicis longus and extensor pollicis brevis the lateral boundary. • The radial artery crosses the oor of the snuff box and travels between the two heads of the 1st dorsal interosseous.

LATERAL WRIST AND HAND

Up p e r Lim b

173

EPL

1st dorsal interosseous

Adductor pollicis (1)

Extensor (dorsal) expansion

EPB 1

Extensor digitorum (6) 1st metacarpal

Extensor pollicis brevis (5) Opponens pollicis Abductor pollicis longus (4) Joint capsule of 1st carpometacarpal joint

2

1st dorsal interosseous (2)

Radial artery

6

APL

6 Extensor pollicis longus (3) Midcarpal joint

5

Extensor carpi radialis brevis Scaphoid bone Styloid process of radius

3 Anatomical snuff box

Wrist joint Extensor carpi radialis longus 6

Radial artery

4 Extensor digitorum (6)

Flexor carpi radialis

Brachioradialis

D. Lateral View

Distal Extent of: EPL Extensor pollicis longus EPB Extensor pollicis brevis APL Abductor pollicis longus

C. Lateral View

LATERAL WRIST AND HAND (continued ) C. Anatom ical snuff box—III. Note the scaphoid bone, the wrist joint proxim al to the scaphoid, and the m idcarpal joint distal to it. D. Surface anatom y. Fracture of the scap hoid often results from a fall on the palm with the hand abducted. The fracture occurs across the narrow part (“waist”) of the scaphoid. Pain occurs primarily on the lateral side of the wrist, especially during dorsi exion and abduction of the hand. Initial

2.88 radiographs of the wrist may not reveal a fracture, but radiographs taken 10 to 14 days later reveal a fracture because bone resorption has occurred. Owing to the poor blood supply to the proximal part of the scaphoid, union of the fractured parts may take several months. Avascular necrosis of the p roxim al frag m ent of the scap hoid (pathological death of bone resulting from poor blood supply) may occur and produce degenerative joint disease of the wrist.

Up p e r Lim b

174

LATERAL WRIST AND HAND

Distal phalanx of 2nd digit

Extensor pollicis longus

1st dorsal interosseous

Proximal phalanx of thumb

Adductor pollicis Extensor pollicis brevis

1st metacarpal 1st dorsal interosseous

1st metacarpal

Abductor pollicis longus

Extensor carpi radialis longus

Trapezium Scaphoid

Scaphoid

Trapezoid

Lunate

Styloid process Grooves for: Abductor pollicis longus Extensor pollicis brevis Extensor carpi radialis longus Extensor carpi radialis brevis

Trapezium

Dorsal tubercle of radius Groove for extensor pollicis longus

Ulnar styloid process Radius

E

F Lateral Views, Right Hand

2.88

LATERAL WRIST AND HAND (continued )

E. Bony hand showing m uscle attachm ents. F. Radiograph. Note that the anatom ical snuff box is lim ited p roxim ally by the styloid process of the radius and distally by the base of

the 1st m etacarpal; p arts of the two lateral b ones of the carp us (scap hoid and trapezium ) form the oor of the snuff box.

Up p e r Lim b

MEDIAL WRIST AND HAND

175

Abductor digiti minimi

Opponens digiti minimi

Opponens digiti minimi

5th metacarpal

5th metacarpal

Extensor carpi ulnaris

Extensor retinaculum

Dorsal branch of ulnar nerve

A

Basilic vein of forearm

Opponens Digiti Flexor brevis minimi

Extensor carpi ulnaris Pisiform

Flexor carpi ulnaris

Pisometacarpal ligament

Abductor digiti minimi

Dorsal carpal branch of ulnar artery

Subcutaneous part of ulna

Flexor carpi ulnaris

Extensor carpi ulnaris

Pisohamate ligament

Hamate

Abductor digiti minimi Triquetrum

Flexor carpi ulnaris Pisiform

Styloid process of ulna

Lunate

Dorsal branch of ulnar nerve Basilic vein of forearm

B

C Medial Views

MEDIAL WRIST AND HAND A. Super cial dissection. B. Deep dissection. C. Bony hand showing sites of m uscular and ligam entous attachm ents. The extensor carpi ulnaris is inserted directly into the base of the 5th m etacarpal, but the exor carpi ulnaris inserts indirectly to the base of the

2.89 5th m etacarp al via the pisiform and pisoham ate and pisom etacarpal ligam ents. These ligam ents are often considered to be a part of the distal attachm ent of exor carp i ulnaris.

Up p e r Lim b

176

BONES AND JOINTS OF WRIST AND HAND

Smooth area for fingernail

Phalanges: Distal

For flexor digitorum profundus

Distal phalanx

Middle Proximal

For fibrous digital sheath

Head of middle phalanx Head of proximal phalanx

Head Tubercle 5

4

3

2

Hook of hamate

3

2 1st to 5th metacarpal

1

Head 4

1

Base

Trapezoid

Capitate Pisiform Triquetrum Lunate

Body 1st to 5th (shaft) Metacarpal

5

Tubercle of trapezium Tubercle of scaphoid

A. Palmar View

Capitate Hamate Carpal bones Triquetrum

Trapezium Trapezoid Scaphoid

Lunate

B. Dorsal View

DIP D PIP

M

MCP Pr D

2.90

BONES AND IMAGING OF WRIST AND HAND

A. Palmar view. B. Dorsal view. C. Three-dimensional computergenerated image of wrist and hand. Letters refer to structures (D). The eight carpal bones form two rows: in the distal row, the ham ate, cap itate, trap ezoid, and trapezium , the trapezium form ing a saddle-shaped joint with the 1st m etacarpal; and in the p roxim al row, the scap hoid, lunate, and p isiform , the p isiform being superim posed on the triquetrum . Severe crush in g in jurie s o f t h e h an d m ay produce m ultiple m etacarpal fractures, resulting in instability of the hand. Sim ilar injuries of the distal phalanges are com m on (e.g., when a nger is caught in a car door). A fract ure o f a d ist al p h alan x is usually com m inuted, and a painful h e m at o m a (collection of blood) develops. Fract ure s o f t h e p ro xim al an d m id d le p h alan g e s are usually the result of crushing or hyp ertension injuries.

Pr

F 3

4

F

2

5

1 H Su

C Td Tz

P T L Hu

C. Anterior View

S Sr

Up p e r Lim b

BONES AND JOINTS OF WRIST AND HAND

177

Distal interphalangeal (DIP) joint

Proximal interphalangeal (PIP) joint Distal (D) Phalanges

Metacarpophalangeal (MCP) joint

Middle (M) Distal phalanx (D) Proximal (Pr) Proximal phalanx (Pr) Head

Sesamoid bone (F)

Metacarpal Shaft (body)

Muscle and soft tissue

Base

4

Hook of hamate (H)

3

5

2

Trapezoid (Td)

1

Trapezium (Tz)

Pisiform (P)

Capitate (C)

Triquetrum (Tq) Styloid process of ulna (Su)

Scaphoid (S) Lunate (L)

Head of ulna (Hu)

Styloid process of radius (Sr) Ulnar notch of radius

Ulna (U)

D. Anterior View

3

4

5

1

2

Carpometacarpal joint

5 H Ulnar collateral ligament (Su)

P

C

Tq

4 H

Midcarpal joint

S Sr

2 Td

C

Tz

S L

Radiocarpal (wrist) joint

A Su

Hu

Ulna (U)

Sr

Hu J U

Radius (R)

E

3

Tq

Radial collateral joint

L

Articular disc (A) Distal radio-ulnar joint (J)

Tz

Td

Radius (R)

R

F

BONES AND IMAGING OF WRIST AND HAND (continued ) D. Radiograp h. E. Coronal section. F. Coronal MRI. Letters refer to structures ( D) .

2.90

Up p e r Lim b

178

BONES AND JOINTS OF WRIST AND HAND

Articular disc Extensor digiti minimi

Extensor digitorum Extensor indicis

Extensor pollicis longus

Extensor carpi ulnaris

Extensor carpi radialis longus Extensor carpi radialis brevis

Styloid process Fovea

Styloid process of ulna

Ligamentous posterior border of articular disc

Articular area for lunate Dorsal tubercle of radius Articular area for scaphoid

Ligamentous attachment of articular disc

Extensor pollicis brevis Abductor pollicis Ligamentous anterior longus border of articular disc

Head of ulna Radius

A. Inferior View

B. Inferior View

Styloid process of radius Perforation

Transverse carpal ligament (flexor retinaculum)

Flexor carpi radialis tendon

Carpal tunnel

Pisiform

MEDIAL

Lunate

LATERAL Scaphoid

Triquetrum

Synovial membrane Styloid process of ulna

Synovial fold Styloid process of radius

Articular disc

Distal end of radius

Ligamentous anterior border of articular disc Pronator quadratus

C. Anterior View

2.91

RADIOCARPAL (WRIST) JOINT

A. Distal ends of radius and ulna showing grooves for tendons on the posterior aspects. B. Articular disc. The articular disc unites the distal ends of the radius and ulna; it is brocartilaginous at the triangular area between the head of the ulna and the lunate bone but ligam entous and pliable elsewhere. The cartilaginous part of the articular disc

com m only has a ssure or perforation, as shown here, associated with a roughened surface of the lunate. C. Articular surface of the radiocarpal joint, which is opened anteriorly. The lunate articulates with the radius and articular disc; only during adduction of the wrist does the triquetrum com e into articulation with the disc.

Up p e r Lim b

BONES AND JOINTS OF WRIST AND HAND

179

Deep branch of ulnar nerve Deep branch of ulnar artery

Flexor retinaculum (transverse carpal ligament) Trapezium Median nerve Tubercle of scaphoid Palmar ligament

Pisiform

MEDIAL

Triquetrum

Radial artery Capitate

Lunate

Intercarpal joint

Ligamentous border of articular disc

Palmar radiocarpal ligaments

Styloid process of ulna

Styloid process of radius

Distal radio-ulnar joint

Radiocarpal (wrist) joint

Sacciform recess of distal radio-ulnar joint

Radius Tendon of abductor pollicis longus

Ulna

A. Anterior View

LATERAL

Flexor retinaculum (transverse carpal ligament) Tubercle of trapezium Trapezium (Tz) Carpal tunnel Median nerve Trapezoid (Td) MEDIAL

LATERAL

Hook of hamate

Capitate (C) Synovial fold

Hamate (H)

Lunate (L) Scaphoid (S)

Triquetrum

H C Td Tz S L Pisiform Flexor carpi ulnaris

B. Anterior View, Right Limb

Ulna

Flexor carpi radialis Flexor retinaculum Radius

RADIOCARPAL (WRIST) AND MIDCARPAL (TRANSVERSE CARPAL) JOINT A. Lig am ents. The hand is forcibly extended. The p alm ar radiocarpal ligam ents pass from the radius to the two rows of carpal bones; they are strong and directed so that the hand m oves with the radius during sup ination. B. Articular surfaces of m idcarp al (transverse carp al) joint, opened anteriorly.

2.92

Note that the exor retinaculum (transverse carp al lig am ent) is cut. The proxim al part of the ligam ent, which spans from the pisiform to the scaphoid, is relatively weak; the distal part, which passes from the hook of the ham ate to the tubercle of the trapezium , is strong.

180

Up p e r Lim b

BONES AND JOINTS OF WRIST AND HAND

2

3 4

MEDIAL

LATERAL

1

5

1st metacarpal

5th metacarpal Trapezoid Trapezium Hamate

Tubercle

Hook of hamate Tubercle

Pisiform

Capitate Triquetrum Scaphoid

Lunate

Radius

Ulna

A Anterior View, Right Limb

3 2

4

Base of metacarpals 1–5

5 1

Carpal bones: Tz Trapezium Distal row Td Trapezoid C Capitate H Hamate (HH hook of hamate)

B

2.93

S L Proximal row Tq P

C

HH Scaphoid Lunate Triquetrum Pisiform

Td Tz

H S

Tq P

L

CARPAL BONES AND BASES OF METACARPALS

A. Open intercarp al and carp om etacarp al (CMC) joints. The dorsal ligam ents rem ain intact and all the joints have been hyperextended. B. Articular surfaces of the CMC joints. Note that the 1st CMC joint is saddle-shaped and especially m obile, allowing opposition of the thum b; the 2nd and 3rd CMC joints have interlocking surfaces and are practically im m obile; and the 4th and 5th are hinge-shaped synovial joints with lim ited m ovem ent.

An t e rio r d islo ca t io n o f t h e lu n a t e is a serio u s in ju ry th at u su ally resu lt s fro m a fall o n th e ext en d ed wrist. Th e lun ate is p u sh ed t o t h e p alm ar su rface o f th e wrist an d m ay co m p ress th e m ed ian n erve an d lead to carp al tu n n el syn d ro m e. Becau se o f p o o r b lo o d su p p ly, a va scu la r n e cro sis o f t h e lu n a t e m ay o ccu r.

Up p e r Lim b

BONES AND JOINTS OF WRIST AND HAND

Proximal interphalangeal joint

Middle phalanx

181

Collateral ligament Distal phalanx

Collateral ligament Distal interphalangeal joint Proximal phalanx

“Cordlike” part

Collateral ligament

“Fanlike” part Collateral ligament

Palmar ligament (plate)

Palmar ligament (plate)

Metacarpal

A

C

B Lateral Views of Right 3rd Digit

COLLATERAL LIGAMENTS OF METACARPOPHALANGEAL AND INTERPHALANGEAL JOINTS OF THIRD DIGIT A. Extended m etacarpophalangeal (MCP) and distal interphalangeal (IP) joints. B. Flexed interphalangeal joints. C. Flexed MCP joint. • A brocartilaginous plate, the palm ar ligam ent, hangs from the base of the proxim al phalanx; is xed to the head of the m etacarp al by the weaker, fanlike part of the collateral ligam ent ( A) ; and m oves like a visor across the m etacarpal head ( C) . The IP joints have sim ilar p alm ar ligam ents. • Th e extrem ely stron g , cord like p arts of th e collateral lig am en ts of th is join t ( A a n d B) are eccen trically attach ed to

2.94

th e m etacarp al h ead s; th ey are slack d urin g exten sion an d taut d urin g exion ( C) , so th e n g ers can not b e sp read ( ab d ucted ) un less th e h an d is op en ; th e IP join ts h ave sim ilar collateral lig am en ts. Skie r’s t h um b refers to the rup ture or chronic laxity of the collateral ligam ent of the 1st m etacarpophalangeal joint. The injury results from hyperextension of the joint, which occurs when the thum b is held by the ski pole while the rest of the hand hits the ground or enters the snow.

182 TABLE 2.16

Up p e r Lim b

BONES AND JOINTS OF WRIST AND HAND

LESIONS OF NERVES OF UPPER LIMB

Nerve Injury

Injury Description

Impa irments

Clinica l Aspect

Long thoracic nerve

Stab wound Mastectomy

Abduction of shoulder joint and protraction of the scapula is compromised

Test: Pushing against a wall causes winging of scapula

Axillary nerve

Surgical neck fracture of humerus Anterior dislocation of shoulder joint

Abduction of shoulder joint to horizontal is compromised; Test: Abduct shoulder joint to horizontal and ask patient to hold posensory loss on lateral side of upper arm sition against a downward pull on the distal arm

Radial nerve

Midshaft fracture of humerus Badly tted crutch Arm draped over a chair

Extension at wrist and joints of digits is lost; supination of forearm is compromised; sensory loss on posterior arm and forearm, and lateral aspect of dorsum of hand

Wrist drop

A

B

Median nerve at elbow

Supra-epicondylar fracture of humerus

Flexion of wrist joint is weakened; hand will deviate to ulnar side during exion of wrist joint; exion of DIP, PIP, and MCP joints of index and middle digits is lost; abduction, opposition and exion of thumb joints are lost; sensory loss on palmar and dorsal aspects of index, middle, and lateral half of ring ngers and palmar aspect of thumb

Absence of thumb opposition Lagging 2nd and 3rd digits when making a st

A. Inability to oppose thumb

(movement occurs at carpometacarpal joint)

Atrophy of thenar eminence, thumb adducted and extended

B. Simian hand

Median nerve at wrist

Wrist laceration Carpal tunnel syndrome

Weakened exion of MCP joints of index and middle ngers; opposition and abduction of CMC and MCP joint of thumb lost; sensory loss same as for median nerve injury at elbow

Test: Make a “O” with thumb and index nger

Ulnar nerve at elbow

Fracture of medial epicondyle of humerus

Hand will deviate to radial side during exion of wrist joint; exion of DIP joints of ring and little nger lost; exion at MCP joint and extension at PIP and DIP joints of little and ring nger are lost; adduction and abduction of MCP joints of digits 2–5 lost; adduction of thumb lost; sensory loss on palmar and dorsal aspects of little and medial half of ring ngers

law hand Claw

Palmar digital branches Palmar branch

A. Claw hand Ulnar nerve at wrist

Wrist laceration

Flexion at MCP joint and extension at PIP and DIP joints of little and ring ngers lost; adduction and abduction of MCP joints of digits 2–5 lost; adduction of thumb lost; sensory loss same as for ulnar nerve injury at elbow

CMC, carpometacarpal joint; DIP, distal interphalangeal joint; MCP, metacarpophalangeal joint; PIP, proximal interphalangeal joint.

B. Sensory distribution of ulnar nerve

Test: Hold paper between middle and ring ngers.

FUNCTION OF HAND: GRIPS AND PINCHES

A. Lateral View

B. Anterior View

D. Medial View

Up p e r Lim b

183

C. Medial View

E. Medial View

F. Medial View

I. Lateral View

G.

Anterior View

H. Anterior View

FUNCTIONAL POSITIONS OF HAND A. Cylindrical (p ower) grasp . When grasp ing an object, the m etacarpophalangeal and interphalangeal joints are exed, but the radiocarpal joints are extended. Without wrist extension, the grip is weak and insecure. B. Hook grasp. This grasp involves prim arily the long exors of the ngers, which are exed to a varying degree

2.95 depending on the size of the object. C. Trip od (three-jaw chuck) pinch. D. and E. Fingertip pinch. F. Rest p osition of hand. Casts for fractures are applied m ost often with the hand in this position. G. Loose cylindrical grasp . H. Firm cylindrical (power) grasp. I. Disc (power) grasp .

184

Up p e r Lim b

IMAGING AND SECTIONAL ANATOMY

ANTERIOR

ANTERIOR

CV BB BV PMj

LHB

BC

CV LI

D

PMi

MT H

F

SHB D

D

T

H

LAT

L

BV F

LT LAT TL

SC

B POSTERIOR

D LT

SA

ANTERIOR CV

TM

BB

A POSTERIOR

BV

BS

Key for A, B, and C: BB BC BR BS BV CV D F H L LAT LHB LI LT MI MT PMi PMj SA SC SHB T TL TM TR

Biceps brachii Brachialis Brachioradialis Basilic Vein Brachial vessels and nerves Cephalic vein Deltoid Fat in axilla Humerus Lung Lateral head of triceps brachii Long head of biceps brachii Lateral intermuscular septum Long head of triceps brachii Medial intermuscular septum Medial head of triceps brachii Pectoralis minor Pectoralis major Serratus anterior Subscapularis Short head of biceps brachii Deltoid tuberosity Teres major and latissimus dorsi Teres minor Triceps brachii

BR

BC

MI

A

TR B

C

C POSTERIOR

2.96

TRANSVERSE (AXIAL) MRIs OF ARM

A. Transverse MRI through the proxim al arm . B. Transverse MRI through the m iddle of the arm . C. Transverse MRI throug h the distal arm .

Up p e r Lim b

IMAGING AND SECTIONAL ANATOMY POSTERIOR

Key

Ulna (U)

16

15

14 Radius (R)

10

1 Pronator teres 2 Flexor carpi radialis 3 Palmaris longus 4 Flexor carpi ulnaris 5 Flexor digitorum superficialis 6 Flexor digitorum profundus 7 Flexor pollicis longus Extensors: Brachioradialis Extensor carpi radialis longus Extensor carpi radialis brevis Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris Abductor pollicis longus Extensor pollicis brevis Extensor pollicis longus (extensor indicis)

13

11

Flexors:

8 9 10 11 12 13 14 15 16

Posterior interosseous artery and nerve

12 Extensor–supinator compartment Flexor–pronator compartment

185

Interosseous membrane

9 6

7

88

6

5

11

4

Anterior interosseous artery and nerve

5 2

3 Ulnar nerve and artery

Superficial branch of radial nerve

Radial artery

Median nerve ANTERIOR

A. Anterosuperior View ANTERIOR

Ulnar vessels and nerve Radial vessels

5 2

A and B 4 Cephalic vein

8

Anterior interosseous vessels and nerve

7

6

LATERAL 6 9

14

10

TRANSVERSE SECTIONS AND TRANSVERSE (AXIAL) MRIs OF FOREARM

16

R

2.97

A. Stepp ed transverse sections of the anterior and p osterior com p artm ents. B. Transverse MRI through the p roxim al forearm .

13 11

B. Transverse MRI

POSTERIOR

U

MEDIAL

186

Up p e r Lim b

IMAGING AND SECTIONAL ANATOMY ANTERIOR Key for C and D:

PT

CV

FDS

BV BR

FCU

BB

LATERAL

MEDIAL R

FDP U

ECRL ECRB

SP AN ECU

ED

C. Transverse MRI

AN APL BB BR BV CV ECRB ECRL ECU ED EPB EPL FCR FCU FDP FDS FPL PQ PT R SP U UV

Anconeus Abductor pollicis longus Biceps brachii Brachioradialis Brachial vessels Cephalic vein Extensor carpi radialis brevis Extensor carpi radialis longus Extensor carpi ulnaris Extensor digitorum Extensor pollicis brevis Extensor pollicis longus Flexor carpi radialis Flexor carpi ulnaris Flexor digitorum profundus Flexor digitorum superficialis Flexor pollicis longus Pronator quadratus Pronator teres Radius Supinator Ulna Ulnar vessels and nerve

POSTERIOR

ANTERIOR FCR

UV

FCU

FDS

C

FDP

PQ FPL

LATERAL

MEDIAL

EPL R

ECU EPB ED

APL

D. Transverse MRI

2.97

U

POSTERIOR

TRANSVERSE SECTIONS AND TRANSVERSE (AXIAL) MRIs OF FOREARM (continued )

C. Transverse MRI through the m iddle forearm . D. Transverse MRI through the distal forearm .

D

Up p e r Lim b

IMAGING AND SECTIONAL ANATOMY

1

19

2

16

Pisiform (P)

3

Triquetrum (T)

4 P

187

Flexor retinaculum

6

18 18 18 18 17 17 17

7

5

Carpal tunnel

8

T S

H C

Lunate (L)

10

Scaphoid (S)

15 11

14 13

9 12

A. Transverse MRI

P2

P1

D2

D3 C

P3

D1

B

D4 D

E

6

II

III

4

IV

I

I

V

A

I

C&D A

I I

Add pollicis

4 TH

8 H Tm P

FT

B. Coronal MRI

TRANSVERSE (AXIAL) SECTION AND MRIs THROUGH CARPAL TUNNEL A. Transverse MRI through the p roxim al carpal tunnel. Num bers and letters in MRI refer to structures ( D) . B. Coronal MRI of wrist and hand showing the course of the long exor tendons in the carpal tunnel. Num bers and letters in MRI refer to structures ( D) .

2.98

A–E, proxim al p halanges; FT, long exor tendons; H, hook of ham ate; I, interossei; P, p isiform ; TH, thenar m uscles; Tm, trapezium ; 1–5, head s of m etacarpals.

Up p e r Lim b

188

IMAGING AND SECTIONAL ANATOMY

2

HH Carpal tunnel

Tm

H

19

Tz

C

2

3

16

5

4

7

6

18 18 18 HH 18 17 17 17

8 Ulnar nerve

Tm

H C

9

Tz

15

10 14

11 13

Ulnar artery

Carpal tunnel (outlined in purple)

Flexor retinaculum Median nerve Flexor carpi radialis

FDS (1–4) FDP (1–4)

Flexor pollicis longus

Common synovial sheath of FDS and FDP

Trapezium

Hamate Trapezoid

12 Capitate

C. Transverse MRI

Palmaris longus (1)

Flexor retinaculum (2) Median nerve (3) Flexor pollicis longus (4) Thenar muscles (5)

Ulnar artery (19)

Flexor carpi radialis (6)

Ulnar nerve (19)

Trapezium (Tm)

Flexor digitorum superficialis (18) Extensor pollicis brevis (7) Abductor pollicis longus (8)

Hook of hamate (HH) Flexor digitorum profundus (17)

Extensor pollicis longus (9)

Hypothenar muscles (16)

Radial artery (10) Trapezoid (Tz)

Extensor carpi ulnaris (15)

Extensor carpi radialis, longus (11) and brevis (12)

Extensor digiti minimi (14) Hamate (H)

D. Transverse Section

2.98

Capitate (C)

Extensor digitorum (13) Extensor indicis

TRANSVERSE (AXIAL) SECTION AND MRIs THROUGH CARPAL TUNNEL (continued )

C. Transverse MRI through the distal carp al tunnel. Num bers and letters in MRI refer to structures ( D) . D. Transverse section of carpal tunnel through the distal row of carpal bones.

Up p e r Lim b

IMAGING AND SECTIONAL ANATOMY

Flexor digitorum superficialis (10) Flexor digitorum profundus (9)

189

Adductor pollicis (AD) Flexor pollicis longus (4)

Lumbrical (1) and digital artery and nerve (2)

Abductor pollicis brevis (5)

Palmar aponeurosis (3)

Opponens pollicis

Midpalmar space Thenar space

Abductor digiti minimi (8)

Princeps pollicis arteries 1st metacarpal (I) Sesamoid bone (6)

Opponens digiti minimi

Extensor pollicis longus

5th metacarpal (V)

Flexor pollicis brevis

3rd palmar interosseous (P3)

Dorsalis pollicis artery

4th dorsal interosseous (D4)

1st dorsal interosseous (D1)

2nd palmar interosseous (P2) 4th metacarpal (IV) 3rd dorsal interosseous (D3)

Dorsalis indicis artery

Extensor tendons (7)

2nd metacarpal (II)

3rd metacarpal (III) Subaponeurotic areolar space

A

1st palmar interosseous (P1)

A. Transverse Section

2nd dorsal interosseous (D2)

2 3

10

9

1 1 8

1

P3

5

4 6

1

AD

I

P2 P1

V D4

IV

D3

III

II D2

D1

7

B. Transverse MRI

TRANSVERSE SECTION AND MRI THROUGH PALM (METACARPALS) AT LEVEL OF ADDUCTOR POLLICIS A. Anatom ic section. B. MRI

2.99

CHAPTER 3

Th o rax Pectoral Region ..................................................................192 Breast ................................................................................194 Bony Thorax and Joints ......................................................202 Thoracic Wall .....................................................................209 Thoracic Contents .............................................................217 Pleural Cavities ..................................................................220 Mediastinum .....................................................................221 Lungs and Pleura ...............................................................222 Bronchi and Bronchopulm onary Segm ents ........................228 Innervation and Lym phatic Drainage of Lungs ...................234 External Heart ....................................................................236 Coronary Vessels ................................................................246 Conduction System of Heart ..............................................250 Internal Heart and Valves ...................................................251 Superior Mediastinum and Great Vessels ............................258 Diaphragm ........................................................................265 Posterior Thorax ................................................................266 Overview of Autonom ic Innervation ..................................276 Overview of Lym phatic Drainage of Thorax .......................278 Sectional Anatom y and Im aging ........................................280

Th o rax

192

PECTORAL REGION

Clavicular head of pectoralis major

Suprasternal (jugular) notch

Deltoid Clavicle Anterior axillary fold Sternum

Posterior axillary fold Axillary fossa

Sternocostal head of pectoralis major

Areola Xiphoid process

Nipple Serratus anterior

Linea alba

External oblique

Rectus abdominis

Anterior View

3.1

SURFACE ANATOMY OF MALE PECTORAL REGION

• The subject is add ucting the shoulders against resistance to dem onstrate the p ectoralis m ajor m uscle. • The sternum (breastbone) lies subcutaneously in the anterior m edian line and is palpable throughout its length. • The sup rasternal notch can be palpated between the p rom inent m edial ends of the clavicles.

• The pectoralis m ajor m uscle has two parts, the sternocostal and clavicular heads. • The inferior border of the sternocostal head of the pectoralis m ajor m uscle form s the anterior axillary fold. The axillary fossa (“arm pit”) is a surface feature overlying a fat- lled space, the axilla, posterior to the anterior fold. • The m ale nipple overlies the 4th intercostal space.

PECTORAL REGION

Th o rax

193

Supraclavicular nerves (C3 and C4) Clavicle Deltoid Platysma Clavipectoral (deltopectoral) triangle Cephalic vein Skin

Clavicular head Pectoralis major

Pectoral fascia covering pectoralis major Sternocostal head Intercostobrachial nerve (T2)

Lateral mammary and posterior branches of lateral pectoral cutaneous nerves (T3 to T6) (from intercostal nerves)

Serratus anterior

External oblique

Subcutaneous tissue

Lateral mammary branches of lateral pectoral cutaneous branches of intercostal nerves

Medial mammary branches of anterior pectoral cutaneous branches of intercostal nerves Costal cartilage of 6th rib

Anterior View

SUPERFICIAL DISSECTION, MALE PECTORAL REGION • The platysm a m uscle, which descends to the 2nd or 3rd rib, is cut short on b oth sides of the sp ecim en; together with the supraclavicular nerves, it is re ected sup eriorly on the right side. • The p ectoral fascia covers the p ectoralis m ajor. • The clavicle lies deep to the subcutaneous tissue and the platysm a m uscle. • The cep halic vein passes d eep ly in the clavip ectoral (deltopectoral) triangle to join the axillary vein.

3.2 • Supraclavicular (C3 and C4) and upper thoracic nerves (T2 to T6) supply cutaneous innervation to the pectoral region. • The clavipectoral (deltopectoral) triangle, bounded by the clavicle superiorly, the deltoid m uscle laterally, and the clavicular head of the p ectoralis m ajor m uscle m edially, und erlies a surface depression called the infraclavicular fossa.

Th o rax

194

BREAST

Clavicle

Suprasternal (jugular) notch

Manubrium of sternum Deltoid

Anterior axillary fold

Intermammary cleft overlying body of sternum

Nipple

Supernumerary nipple (polythelia)

Areola

Xiphoid process

A. Anterior View

Body of sternum Site of axillary process (tail) Anterior axillary fold

Areolar tubercles

Intermammary cleft Nipple

Nipple

Areola

Areola

Supernumerary nipple (polythelia) Inferior cutaneous crease

B. Anterior View

3.3

C. Anterior View

SURFACE ANATOMY OF FEMALE PECTORAL REGION

A. Overview. B. Breast. The roughly circular base of the fem ale breast extends transversely from the lateral border of the sternum to the m idaxillary line and vertically from the 2nd to 6th ribs. A sm all part of the breast m ay extend along the inferolateral edge of the pectoralis m ajor m uscle toward the axillary fossa, form ing an axillary process or tail (of Spence). C. Areola and nip ple.

Po lym ast ia (sup ernum erary breasts) or p o lyt h e lia (accessory nipples) m ay occur superior or inferior to the norm al pair, occasionally develop ing in the axillary fossa or anterior ab dom inal wall. Supernum erary breasts usually consist of only a rudim entary nipple and areola, which m ay be m istaken for a m ole (nevus) until they change p igm entation with the norm al nip ples during p regnancy.

Th o rax

BREAST

195

Suprasternal (jugular) notch Clavicle

Clavicle Pectoral fascia

Deltoid Cephalic vein

Pectoralis major

Pectoralis major Latissimus dorsi Retromammary space (bursa) consisting of loose connective tissue

Suspensory ligaments of breast Lactiferous duct Axillary process (tail) of breast

Fat

Axillary fat Areola Serratus anterior

A. Anterior View

SUPERFICIAL DISSECTION, FEMALE PECTORAL REGION 12 o’clock Axillary tail Superolateral quadrant

60% 15%

Superomedial quadrant Areola (10%) Nipple

9

Inferolateral quadrant

3

10%

5%

Inferomedial quadrant

6 Right Breast, Anterior View

B. Quadrants of Breast: Percentage of Malignant Tumors

3.4

A. Dissection. • On the specim en’s right side, the skin is rem oved ; on the left sid e, the b reast is sagittally sectioned. • Two thirds of the breast rests on the p ectoral fascia covering the pectoralis m ajor; the other third rests on the fascia covering the serratus anterior m uscle. • The region of loose connective tissue between the pectoral fascia and the deep surface of the breast, the retrom am m ary sp ace (bursa), p erm its the breast to m ove on the deep fascia. Cancer can spread b y contiguity (invasion of adjacent tissue). When breast cancer cells invade the retrom am m ary space, attach to or invade the pectoral fascia overlying the p ectoralis m ajor, or m etastasize to the interpectoral nodes (Fig. 3.7), the breast elevates when the m uscle contracts. This m ovem ent is a clinical sign of ad van ce d can ce r o f t h e b re ast . B. Breast quadrants. For the anatom ical location and description of tum ors and cysts, the surface of the breast is divided into four quadrants. For exam ple, “A hard irregular m ass was felt in the superior m edial quadrant of the breast at the 2 o’clock position, approxim ately 2.5 cm from the m argin of the areola.”

196

Th o rax

BREAST Fat has been removed Suspensory ligament of breast Lobules of fat Suspensory ligament of breast Lactiferous ducts

Nipple

Lactiferous ducts

A. Anterior View

Lobule of mammary gland Terminal duct Lactiferous ducts Lactiferous ducts

Nipple

Areola Lobe of mammary gland

B. Schematic Sagittal Section

3.5

C. Galactogram

FEMALE MAMMARY GLAND

A. Dissection. Areas of subcutaneous fat were rem oved to show the susp ensory ligam ents of the breast. B. Sagittal section. The glandular tissue consists of 15 to 20 lobes, each com posed of lobules. Each lobe has a lactiferous duct that widens to form the lactiferous sinus before op ening on the nip ple. C. Galactogram . This is used to im age the duct system of the breast. Contrast m aterial is injected into the ducts and m am m ogram s are then taken.

Interference with the lymphatic drainage by cancer may cause lym phed em a (edema, excess uid in the subcutaneous tissue), which in turn may result in deviation of the nipple and a leathery, thickened appearance of the breast skin. Prominent (puffy) skin between dimpled pores may develop, which gives the skin an orange-peel appearance (peau d’orange sign). Larger dimples may form if pulled by cancerous invasion of the suspensory ligaments of the breast.

BREAST

Th o rax

197

Pectoral fascia Subcutaneous tissue

Pectoralis major Retromammary space (bursa) Fat Suspensory ligaments of breast Suspensory ligaments

Glandular tissue (mammary lobule) Lactiferous duct

Glandular tissue

Nipple Nipple

Fat

A. Sagittal Breast Section

B. Sagittal Breast MRI

Pectoralis major

Cancer

Orientation for C

Orientation for D

C. MLO Mammogram

IMAGING OF BREAST A. Illustration of sagittal section of breast. B. Sagittal MRI of breast showing m any of the features visible in ( A) . In this MRI, fat app ears very dark, whereas glandular tissue is brighter and the linear suspensory ligam ents clearly visible. The pectoralis m ajor is also apparent as is the pectoralis m inor posterior to it. C. and D. Scanning

D. CC Mammogram

3.6 m am m ogram s, which use x-rays, are done with a m ediolateral oblique (MLO) and a craniocaudal (CC) orientation. These two orientations allow the entire breast to be im aged. A sp eculated m ass (cancer) is identi ed in ( D) .

Th o rax

198

BREAST

Supraclavicular lymph nodes Subclavian lymphatic trunk Infraclavicular lymph nodes

*Apical lymph node

Jugular lymphatic trunk Right internal jugular vein

Lymphatic vessel Right lymphatic duct

*Central lymph nodes

Bronchomediastinal lymphatic trunk

Interpectoral lymph nodes

*Humeral (lateral) lymph nodes

*Pectoral (anterior) lymph nodes

Parasternal lymph nodes

*Subscapular (posterior) lymph nodes

Subareolar lymphatic plexus

*Axillary lymph nodes

A. Anterior View

3.7

LYMPHATIC DRAINAGE OF BREAST

A. Overview. Lym ph drained from the upper lim b and breast passes through nodes arranged irregularly in groups of axillary lym ph nodes: (1) pectoral, along the inferior border of the pectoralis m inor m uscle; (2) subscapular, along the subscapular artery and veins; (3) hum eral, along the distal part of the axillary vein; (4) central, at the base of the axilla, em bedded in axillary fat; and (5) apical,

along the axillary vein between the clavicle and the pectoralis m inor m uscle. Most of the breast drains via the pectoral, central, and apical axillary nodes to the subclavian lym ph trunk, which joins the venous system at the junction of the subclavian and internal jugular veins. The m edial part of the breast drains to the parasternal nodes, which are located along the internal thoracic vessels.

Th o rax

BREAST

Breast

Supraclavicular lymph nodes Pectoralis minor

4

6

Upper Limb

Axillary lymph nodes Location: Inferolateral to pectoralis minor (Level I) 1. Pectoral nodes 2. Subscapular nodes 3. Humeral nodes 4. Central nodes 5. Interpectoral nodes

Subclavian lymphatic trunk

7

5

199

Location: On pectoralis minor (Level II)

Internal jugular vein Right lymphatic duct

1

Right subclavian vein

Axillary vein and artery

Pectoralis major

Apical nodes (6)

3 Parasternal lymph nodes

Infraclavicular (deltopectoral) nodes (7) Location: Superomedial to pectoralis minor (Level III)

2 B.

Anterior View

Subclavian lymph trunk To abdominal (subdiaphragmatic) lymphatics Thoracic duct or right lymphatic duct

Venous angle (junction of internal jugular and subclavian veins)

C.

LYMPHATIC DRAINAGE OF BREAST (continued ) B. Pattern of lym phatic drainage. Bre ast can ce r typically spreads by m eans of lym phatic vessels (lym phogenic m etastasis), which carry cancer cells from the breast to the lym ph nodes, chie y those in the axilla. The cells lodge in the nodes, producing nests of tum or cells (m etastases). Abundant com m unications am ong lym phatic pathways and am ong axillary, cervical, and parasternal nodes m ay

Flow of Lymph from the Breast and Upper Limb to the Venous Angle.

3.7 also cause m etastases from the breast to develop in the supraclavicular lym ph nodes, the opposite breast, or the abdom en. The prognosis of breast cancer has been correlated with the level of m etastasis (Level I, II, or III in C) and to the num ber of involved axillary lym ph nodes. C. Flow of lym p h from the breast and up per lim b to the venous angle.

Th o rax

200

Clavicle

BREAST

4

5

6

7 Clavicle

3

4

5

6

7

3

2

8

8

2

9

9

Sternum

1

1

10

11

Anterior Views

Arteries 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

11

Veins

Lateral mammary branches of lateral cutaneous branches of posterior intercostal arteries Lateral mammary branches of lateral thoracic artery Lateral thoracic artery Pectoral branch of thoraco-acromial artery Axillary artery Mammary branch of anterior intercostal artery Subclavian artery Internal thoracic artery Perforating branches Sternal branches Medial mammary branches

3.8

10

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

Lateral mammary branches of lateral cutaneous branches of posterior intercostal veins Lateral mammary branches of lateral thoracic vein Lateral thoracic vein Pectoral branch of thoraco-acromial vein Axillary vein Mammary branch of anterior intercostal vein Subclavian vein Internal thoracic vein Perforating branches Sternal branches Medial mammary veins

ARTERIAL SUPPLY AND VENOUS DRAINAGE OF BREAST

Arteries enter and veins drain the breast from its superom edial and superolateral aspects; vessels also penetrate the deep surface of the breast. The vessels branch profusely and anastom ose with each other.

Bre ast in cisio n s are placed in the inferior breast quadrants when possible because these q uadrants are less vascular than the sup erior ones.

BREAST

Th o rax

201

Intercostobrachial nerves (T2 and T3) Pectoralis major Lateral mammary branch of lateral pectoral cutaneous branch of intercostal nerve T4

Long thoracic nerve

Nipple

Serratus anterior

Latissimus dorsi

External oblique Posterior branches of lateral abdominal cutaneous nerves

Anterior branches of lateral abdominal cutaneous nerves (T7, T8)

A. Anterolateral View (Male)

T1

C5

C5

C8

T1 T2 T3 T4 T5 T6 T7 T9

T8

B. Anterolateral View (Female)

MUSCLES AND NERVES OF BED OF BREAST

3.9

A. Muscles comprising bed and cutaneous nerves. B. Dermatomes. Lo cal an e st h e sia o f an in t e rcost al sp ace (intercostal nerve block) is produced by injecting a local anesthetic agent around the intercostal nerves between the paravertebral line and the area of required anesthesia. Because any p articular area of skin usually receives innervation from two adjacent nerves, considerable overlap ping of contiguous derm atom es occurs. Therefore, com p lete loss of sensation usually does not occur unless two or m ore intercostal nerves are anesthetized.

202

Th o rax

BONY THORAX AND JOINTS

1st thoracic vertebra

Jugular notch

Sternocostal synchondrosis of 1st rib

Ribs:

Clavicle

1st

2nd Scapula 3rd Manubrium 4th

Manubriosternal joint (sternal angle)

5th

Body

of sternum

Xiphisternal joint

6th

Xiphoid process 7th Costochondral joint 8th Costal cartilage 9th

8th rib 8th intercostal space

10th 12th

Body of 12th thoracic vertebra

Costal margin

10th rib

11th

A. Anterior View

3.10

Infrasternal angle

BONY THORAX

• The thoracic cage consists of 12 thoracic vertebrae, 12 pairs of ribs and costal cartilages, and the sternum . • Anteriorly, the sup erior seven costal cartilages articulate with the sternum ; the 8th, 9th, and 10th cartilages articulate with the cartilage above form ing the costal m argin; the 11th and 12th are “ oating” ribs, that is, their cartilages do not articulate anteriorly. • The clavicle lies over the 1st rib, m aking it dif cult to palpate. The 2nd rib is easily palpable because its costal cartilage articulates

with the sternum at the sternal angle, located at the junction of the m anubrium and body of the sternum . • The 3rd to 10th ribs can be palpated in sequence inferolaterally from the 2nd rib; the fused costal cartilages of the 7th to 10th ribs form the costal arch (m argin), and the tips of the 11th and 12th ribs can be p alp ated posterolaterally. • A rib d islo cat io n is the displacem ent of a costal cartilage from the sternum ; a rib se p arat io n refers to dislocation of the costochondral joint.

Th o rax

BONY THORAX AND JOINTS

203

1st thoracic vertebra

Clavicle 1st rib

Ribs: 1st

Spine of scapula

2nd

3rd Scapula 4th

5th Inferior angle of scapula 7th rib

6th

Angle of the 9th rib

7th 8th

9th intercostal space

9th Floating (free) ribs (11–12)

10th

12th

B. Posterior View

BONY THORAX (continued ) • The superior thoracic aperture (thoracic inlet) is the doorway between the thoracic cavity and the neck region; it is bounded by the 1st thoracic vertebra, the 1st ribs and their cartilages, and the m anubrium of the sternum . • Each rib articulates p osteriorly with the vertebral colum n. • Posteriorly, all ribs angle inferiorly; anteriorly, the 3rd to 10th costal cartilages angle sup eriorly. • The scapula is susp ended from the clavicle and extends across the 2nd to 7th ribs posteriorly.

Spinous process of 1st lumbar vertebra

11th

3.10 • When clinicians refer to the superior thoracic aperture as the thoracic “outlet,” they are em phasizing the im portant nerves and arteries that pass through this aperture into the lower neck and upper lim b. Hence, various types of t h o racic o ut le t syn d ro m e s exist, such as the costoclavicular syndrom e—pallor and coldness of the skin of the up per lim b and dim inished radial pulse—resulting from com p ression of the subclavian artery between the clavicle and the 1st rib.

Th o rax

204

BONY THORAX AND JOINTS

Cut edges of fibrous layer of joint capsule

Jugular (suprasternal) notch

Clavicular notch

Synovial membrane

1st costal cartilage

Articular cavities of sternoclavicular joint

Costal notches: 1st

Articular disc Manubrium

Anterior sternoclavicular ligament

Manubriosternal joint (sternal angle)

Costal notches: 2nd

Clavicular notch

Interclavicular ligament

Manubrium

Clavicle Sternal angle Body (sternebrae):

2nd

Costoclavicular ligament

1st 3rd

1st costal cartilage

Body of sternum

3rd 2nd

Manubrium

B. Anterior View 4th

4th Clavicular notch

Transverse ridge

3rd

Costal cartilages:

5th

5th 1

Xiphisternal joint

6th 7th

7th Manubrium

Xiphoid process

4th

6th

Xiphisternal joint

2 Xiphoid process

Manubriosternal joint

C. Lateral View

A. Anterior View 3 Intra-articular ligament Year of synostosis: In about 10% of adults (30–80 years) Sternebrae

1st

Sternocostal joints

4 Anterior sternocostal radiate ligaments

Body of sternum

21st year± 2nd 3rd

14th year±

5 Interchondral joint

6

7th year±

Anterior costoxiphoid ligament Interchondral ligament

4th

7

Commonly after middle life

8 Xiphoid process

D. Anterior View

3.11

E. Anterior View

STERNUM AND ASSOCIATED JOINTS

A. Parts o f stern u m . B. Stern oclavicu lar jo in t. C. Features of th e lateral asp ect o f th e stern um . D. Ag es of ossification of stern u m . E. Stern o co stal, m an ub riostern al, an d in terch o n d ral jo in ts.

On th e rig h t sid e of th e sp ecim en , th e cortex of th e stern um an d th e extern al surface of th e costal cartilag es h ave b een sh aved away.

BONY THORAX AND JOINTS

Th o rax

205

1st rib Single facet on head Groove for subclavian vein 2nd rib

Scalene tubercle

Groove for subclavian artery

1st rib

Superior facet Inferior facet

Costal angle

Head Neck

Neck

6th rib

B. Superior View

Crest of neck Crest of head

Tubercle

Tubercle

Head

Shaft: Internal surface

Articular part Nonarticular part

Shaft: External surface 8th rib

2nd rib

Costal groove Site of articulation with costal cartilage

Tubercle for serratus anterior

Head

Single facet on head

11th rib

Neck Tubercle

C. Superior View

A. Posterior View 12th rib

RIBS A. “Typical” (6th and 8th) and “atyp ical” (1st and 2nd and 11th and 12th) rib s. B. First rib. C. Second rib.

3.12 Rib fract ure s. The weakest part of a rib is im m ediately anterior to its angle. The m iddle ribs are m ost com m only fractured.

Th o rax

206

BONY THORAX AND JOINTS

Spinous process Foramen transversarium Elements of transverse process: Transverse

C7

Costal Vertebral body

Cervical ribs

A. Superior View 2nd rib

1st rib

Fusion

3rd rib

Supernumerary part of rib and costal cartilage

C. Superior View

3rd rib

B. Anterior View

3.13

Manubrium 3rd costal cartilage

Body

RIB AND STERNUM ANOMALIES

A. Cervical ribs. People usually have 12 rib s on each side, b ut the num ber m ay be increased by the presence of cervical and/ or lum bar ribs (supernum erary ribs) or decreased by a failure of the 12th pair to form . Ce rvical rib s (present in up to 1% of p eop le) articulate with the C7 vertebra and are clinically signi cant because they m ay com press spinal nerves C8 and T1 or the inferior trunk of the brachial plexus supp lying the upp er lim b. Tingling and num bness m ay occur along the m edial border of the forearm . They m ay also com press the subclavian artery, resulting in isch e m ic m uscle p ain (caused by poor blood supply) in the upp er lim b. Lum b ar rib s are less com m on than cervical ribs but have clinical signi cance in that they m ay confuse the identity of vertebral levels in diagnostic im ages. B. Bi d rib. The superior com ponent of this 3rd rib is supernum erary and articulated with the lateral aspect of the 1st sternebra. The inferior com ponent articulated at the junction of the 1st and 2nd sternebrae. C. Bicipital rib. In this specim en, there has been partial fusion of the rst two thoracic ribs. D. Sternal foram en.

Sternal foramen

Xiphoid process

D. Anterior View

BONY THORAX AND JOINTS

Superior articular facet

207

Superior costal (demi-) facet Transverse process

Transverse costal facet for tubercle of 6th rib

6th rib

T6 Joints of head of rib

Transverse process of T7

T7

T6 Rib rotates

Vertebral body

Costotransverse joint Inferior costal (demi-) facet Spinous process of T7

Th o rax

T7 Axis of rotation

7th rib

A. Lateral View Rib glides Superior articular facet

T9

T6

T7

Spinous process of T6

Tubercle of 7th rib

Transverse costal facet for tubercle of 6th rib Crest of head Vertebral body

T10

C. Lateral View

7th rib

B. Posterolateral View

COSTOVERTEBRAL ARTICULATIONS A. and B. Articulating structures. • There are two articular facets on the head of the rib: a larger, inferior costal facet for articulation with the vertebral body of its own num ber, and a sm aller, superior costal facet for articulation with the vertebral body of the vertebra superior to the rib. • The crest of the head of the rib sep arates the superior and inferior costal facets.

3.14 • The sm ooth articular part of the tubercle of the rib, the transverse costal facet, articulates with the transverse process of the sam e num bered vertebra at the costotransverse joint. C. Movem ents at the costotransverse joints. At the 1st to 7th costotransverse joints, the ribs rotate, increasing the anteroposterior diam eter of the thorax; at the 8th, 9th, and 10th, they glide, increasing the transverse diam eter of the upper abdom en.

208

Th o rax

BONY THORAX AND JOINTS

POSTERIOR

ANTERIOR

Anterior longitudinal ligament Radiate ligament of head of rib Superior costotransverse ligament

Intra-articular ligament

Plane of section for B

A. Lateral View

POSTERIOR

Lateral costotransverse ligament

Superior articular process Transverse process Costotransverse joint

Costotransverse ligament

Rib Joint of head of rib

Radiate ligament of head of rib

Vertebral body

B. Superior View ANTERIOR

3.15

LIGAMENTS OF COSTOVERTEBRAL ARTICULATIONS

A. External and internal ligam ents. • The radiate ligam ent joins the head of the rib to two vertebral bodies and the interposed intervertebral disc. • The superior costotransverse ligam ent joins the crest of the neck of the rib to the transverse process ab ove. • The intra-articular lig am ent joins the crest of the head of the rib to the intervertebral disc.

B. Transverse section. • The vertebral body, transverse processes, superior articulating processes, and posterior elements of the articulating ribs have been transversely sectioned to visualize the joint surfaces and ligaments. • The costotransverse ligam ent joins the posterior aspect of the neck of the rib to the ad jacent transverse process. • The lateral costotransverse ligam ent joins the nonarticulating part of the tubercle of the rib to the tip (apex) of the transverse process.

THORACIC WALL

Th o rax

209

Anterior ramus of thoracic nerve Posterior ramus Transverse process Spinal ganglion

Superior costotransverse ligament External intercostal Innermost intercostal

Radiate ligament of head of rib

Subcostales

Internal intercostal membrane

Posterior intercostal vein artery Anterior longitudinal ligament

Intercostal nerve

Collateral branches of intercostal vessels and nerve Rami communicantes Anterior View

Splanchnic nerve

Sympathetic trunk

VERTEBRAL ENDS OF INTERNAL ASPECT OF INTERCOSTAL SPACES • Portions of the innerm ost intercostal m uscle that brid ge two intercostal spaces are called subcostales m uscles. • The internal intercostal m em brane, in the m iddle space, is continuous m edially with the superior costotransverse ligam ent. • Note the order of the structures in the m ost inferior sp ace: posterior intercostal vein and artery, and intercostal nerve; note also their collateral branches.

3.16

• The anterior ram us crosses anterior to the superior costotransverse ligam ent; the posterior ram us is posterior to it. • The intercostal nerves attach to the sym pathetic trunk by ram i com m unicantes; the splanchnic nerve is a visceral branch of the trunk.

Th o rax

210

THORACIC WALL

Longissimus Iliocostalis

Levatores costarum

7th rib Angle of 8th rib Posterior ramus of thoracic nerve

Posterior intercostal vessels and intercostal nerve, posterior to transparent parietal pleura covering the lung Collateral branch of intercostal nerve Lateral costotransverse ligament Innermost intercostal

Internal intercostal Semispinalis Tip of transverse process Posterior View

3.17

Internal intercostal membrane of the 10th intercostal space

VERTEBRAL ENDS OF EXTERNAL ASPECT OF INFERIOR INTERCOSTAL SPACES

• The iliocostalis and longissim us m uscles have been rem oved, exposing the levatores costarum m uscle. Of the ve intercostal spaces shown, the superior two (6th and 7th) are intact. In the 8th and 10th spaces, varying portions of the external intercostal m uscle have been rem oved to reveal the underlying internal intercostal m em brane, which is continuous with the internal intercostal m uscle. In the 9th space, the levatores costarum m uscle has been rem oved to show the posterior intercostal vessels and intercostal nerve. • The intercostal vessels and nerve disapp ear laterally between the internal and innerm ost intercostal m uscles. • The intercostal nerve is the m ost inferior of the neurovascular trio (posterior intercostal vein and artery and intercostal nerve) and the least sheltered in the intercostal groove; a collateral branch arises near the angle of the rib. • Th oraco ce n t e sis. Som etim es it is necessary to insert a hypoderm ic needle through an intercostal space into the pleural cavity (see Fig. 3.27) to obtain a sam ple of pleural uid or to rem ove blood or pus. To avoid dam age to the intercostal nerve and vessels, the needle is inserted superior to the rib, high enough to avoid the collateral branches.

External intercostal

Th o rax

THORACIC WALL

211

Lateral cutaneous branch of intercostal nerve

External intercostal 9th rib Internal intercostal

Innermost intercostal

Internal intercostal 10th intercostal nerve

Rectus abdominis

Transversus abdominis

Internal oblique

External oblique Anterior View

ANTERIOR ENDS OF INFERIOR INTERCOSTAL SPACES

3.18

• The bers of the external intercostal and external oblique m uscles run inferom edially. • The internal intercostal and internal obliq ue m uscles are in continuity at the ends of the 9th, 10th, and 11th intercostal sp aces. • The intercostal nerves lie deep to the internal intercostal m uscle but sup er cial to the innerm ost intercostal m uscle; anteriorly, these nerves lie super cial to the transversus thoracis or transversus abdom inis m uscles. • Intercostal nerves run parallel to the ribs and costal cartilages; on reaching the ab dom inal wall, nerves T7 and T8 continue sup eriorly, T9 continues nearly horizontally, and T10 continues inferom edially toward the um bilicus. These nerves provide cutaneous innervation in overlapping segm ental bands.

Th o rax

212

Anterior ramus (intercostal nerve)

THORACIC WALL

Posterior branch of posterior intercostal artery

Posterior ramus

Internal intercostal membrane

Posterior intercostal artery

External intercostal Lateral pectoral cutaneous branch

Lateral pectoral cutaneous branch

Parietal pleura (cut edge) Aorta Sympathetic trunk Rami communicantes Innermost intercostal

Internal intercostal

Common membrane of innermost intercostal and transversus thoracis

Site of anastomosis/potential collateral pathway between posterior and anterior intercostal arteries

Transversus thoracis

External intercostal membrane Transverse Section

3.19

Anterior intercostal artery Anterior pectoral cutaneous branch

Internal thoracic artery Anterior perforating branch

CONTENTS OF INTERCOSTAL SPACE, TRANSVERSE SECTION

• The diagram is sim pli ed by showing nerves on the right and arteries on the left. • The three m usculom em branous layers are the external intercostal m uscle and m em brane, internal intercostal m uscle and m em brane, and the innerm ost intercostal m uscle, transversus thoracis m uscle, and the m em brane connecting them . • The intercostal nerves are the anterior ram i of spinal nerves T1 to T11; the anterior ram us of T12 is the subcostal nerve.

• Posterior intercostal arteries are branches of the aorta (the superior two spaces are supp lied from the superior intercostal branch of the costocervical trunk); the anterior intercostal arteries are branches of the internal thoracic artery or its branch, the m usculophrenic artery. • The posterior ram i innervate the deep back m uscles and skin adjacent to the vertebral colum n.

THORACIC WALL

Th o rax Ribs:

Ribs: 1 2

4 5 6 7 8

1

Serratus posterior superior

1

3

Innermost intercostal

213

2 3

2

S t e r n u m

4 3

5 6

4

Transversus thoracis

5

7

Levatores costarum

8 6

9

9 7

10 11

8

12

9

10

Serratus posterior inferior

11 12

10

Anterior View

External intercostal

Subcostales

Muscles removed

Posterior View Manubrium

External intercostal membrane Body of sternum

External intercostal

Internal intercostal

Internal intercostal

Lateral View

TABLE 3.1

MUSCLES OF THORACIC WALL

MUSCLES OF THORACIC WALL

Muscles

Superior Atta chment

Inferior Atta chment

Innerva tion

Internal intercostal

Ma in Action a During forced inspiration: elevate ribsa

External intercostal Inferior border of ribs

Superior border of ribs below

Innermost intercostal

a

3.20

Intercostal nerve

During forced respiration: interosseous part depresses ribs; interchondral part elevates ribsa

Transversus thoracis

Posterior surface of lower sternum

Internal surface of costal cartilages 2–6

Weakly depress ribs

Subcostales

Internal surface of lower ribs near their angles

Superior borders of 2nd or 3rd rib below

Probably act in same manner as internal intercostal muscles

Levatores costarum

Transverse processes of C7–T11

Subjacent ribs between tubercle and angle

Posterior rami of C8–T11 nerves

Elevate ribs

Serratus posterior superior

Nuchal ligament, spinous processes of C7–T3 vertebrae

2nd–4th ribs near their angles

2nd–5th intercostal nerves

Elevate ribsb

Serratus posterior inferior

Spinous processes of T11–L2 vertebrae

Inferior borders of 8th–12th ribs near their angles

9th–11th intercostal nerves, subcostal (T12) nerve

Depress ribsb

The tonus of the intercostal muscles keep intercostal spaces rigid, thereby preventing them from billowing (bulging) out during expiration and from being drawn in during inspiration. The role of individual intercostal muscles and accessory muscles of respiration in moving the ribs is dif cult to interpret despite many electromyographic studies. b Action traditionally assigned on the basis of attachments; these muscles appear to be largely proprioceptive in function.

Th o rax

214

THORACIC WALL

Sternocleidomastoid

Clavicular head Sternal head

Subclavius

Posterior Scalene Middle Anterior

Axillary vein Axillary artery Brachial plexus Pectoralis minor Common origin of coracobrachialis and short head of biceps brachii

Subclavian vein Sternothyroid Sternohyoid

Tendon of long head of biceps brachii

1st intercostal nerve Parasternal lymph node 2nd intercostal nerve Internal thoracic

Pectoralis major

vein artery

3rd costal cartilage External intercostal 4th rib

Anterior intercostal

artery vein

Internal intercostal

Internal intercostal deep to external intercostal membrane

Serratus anterior Pectoralis major

Transversus thoracis

External oblique Rectus abdominis 8th costal cartilage

Anterior View

3.21

EXTERNAL ASPECT OF THORACIC WALL

• H-sh ap ed cuts were m ad e th roug h th e p erich on d rium of th e 3rd an d 4th costal cartilag es to sh ell out seg m en ts of cartilag e. • During surgery, re t ain in g p e rich o n d rium p rom otes regrowth of rem oved cartilages. • The internal thoracic (internal m am m ary) vessels run inferiorly deep to the costal cartilages and just lateral to the edge of the sternum , providing anterior intercostal b ranches.

• The parasternal lym ph nodes (green) receive lym phatic vessels from the anterior parts of intercostal spaces, the costal p leura and diaphragm , and the m edial part of the breast. • The subclavian vessels are “sandwiched” between the 1st rib and clavicle and are “padded” by the subclavius. • Surg ical access to th orax. To gain access to the thoracic cavity for surgical procedures, the sternum is divided in the median plane (median sternotomy) and retracted (spread apart). After surgery, the halves of the sternum are held together with wire sutures.

THORACIC WALL

Sternohyoid

Th o rax

215

Sternothyroid

Subclavian artery Anterior scalene 1st rib

Brachiocephalic vein

Internal thoracic vein 2nd rib

Internal thoracic artery 2nd intercostal nerve

Internal intercostal

Body of sternum

Anterior intercostal vein Anterior intercostal artery Internal intercostal

Transversus thoracis

Xiphoid process Diaphragm Superior epigastric artery Musculophrenic artery

Transversus abdominis

Transversus abdominis

Posterior View

INTERNAL ASPECT OF THE ANTERIOR THORACIC WALL • The inferior portions of the internal thoracic vessels are covered posteriorly by the transversus thoracis m uscle; the superior portions are in contact with the parietal pleura (rem oved). • The transversus thoracis m uscle (superior to diap hragm ) is continuous with the transversus abd om inis m uscle (inferior to diaphragm ); these form the innerm ost layer of the three at m uscles of the thoracoabdom inal wall.

3.22 • The internal thoracic (internal m am m ary) artery arises from the subclavian artery and is accom p anied by two venae com itantes up to the 2nd costal cartilage in this specim en and, sup erior to this, by the single internal thoracic vein, which drains into the brachiocephalic vein.

Th o rax

216

THORACIC WALL

Sternal head Clavicular head

Posterior Scalene Middle Anterior

Sternocleidomastoid

1st rib Manubrium of sternum

Clavicle 2nd rib

External intercostal

Serratus posterior superior

Interchondral part of internal intercostal Costal cartilage

Interosseous part of internal intercostal

Central tendon of diaphragm Rectus abdominis

External oblique

Diaphragm Vertebral attachment of diaphragm

Internal oblique Costal margin

3.23

Transversus abdominis

MUSCLES OF RESPIRATION

TABLE 3.2

MUSCLES OF RESPIRATION Inspira tion

Normal (Quiet)

Active (Forced)

a

Expira tion

Major

Diaphragm (active contraction)

Passive (elastic) recoil of lungs and thoracic cage

Minor

Tonic contraction of external intercostals and interchondral portion of internal intercostals to resist negative pressure

Tonic contraction of muscles of anterolateral abdominal walls (rectus abdominis, external and internal obliques, transversus abdominis) to antagonize diaphragm by maintaining intra-abdominal pressure

In addition to the above, active contraction of sternocleidomastoid, descending (superior) trapezius, pectoralis minor, and scalenes, to elevate and x upper rib cage

In addition to the above, active contraction of muscles of anterolateral abdominal wall (antagonizing diaphragm by increasing intra-abdominal pressure and by pulling inferiorly and xing inferior costal margin): rectus abdominis, external and internal obliques, and transversus abdominis

External intercostals, interchondral portion of internal intercostals, subcostales, levatores costarum, and serratus posterior superiora to elevate ribs

Internal intercostal (interosseous part) and serratus posterior inferiora to depress ribs

Recent studies indicate that the serratus posterior superior and inferior muscles may serve primarily as organs of proprioception rather than motion.

Th o rax

THORACIC CONTENTS

Right vagus nerve

217

Internal jugular vein

Right subclavian artery

Trachea Left subclavian vein

Right subclavian vein

Apex of left lung Right brachiocephalic vein

Left brachiocephalic vein

Right phrenic nerve

Left vagus nerve Arch of aorta

Superior lobe of right lung

Superior lobe of left lung Left phrenic nerve

Superior vena cava

Root of lung Costal surface of lung

Parietal layer of serous pericardium

Horizontal fissure

Fibrous pericardium and mediastinal part of parietal pleura

Middle lobe of right lung

Mediastinal surface of lung Oblique fissure

Oblique fissure

Lingula Inferior lobe of right lung

Inferior lobe of left lung

Diaphragm

Sternocostal surface of heart covered with visceral layer of serous pericardium Anterior View

THORACIC CONTENTS IN SITU • The brous p ericardium , lined b y the p arietal layer of serous pericardium , is rem oved anteriorly to exp ose the heart and great vessels. • The right lung has three lobes; the superior lobe is sep arated from the m iddle lobe by the horizontal ssure, and the m iddle lobe is sep arated from the inferior lobe by the oblique ssure.

3.24 The left lung has two lobes, superior and inferior, separated by the oblique ssure. • The anterior border of the left lung is re ected laterally to visualize the phrenic nerve passing anterior to the root of the lung and the vagus nerve lying anterior to the arch of the aorta and then passing posterior to the root of the lung .

Th o rax

218

THORACIC CONTENTS

1st rib Right common carotid artery

Apex of left lung

Right internal jugular vein Right subclavian artery Arch of aorta

Right subclavian vein

Left pulmonary artery Pulmonary trunk

4th rib Right atrium

Cardiac notch of left lung Apex of heart 6th rib Lingula

Diaphragm

8th rib

Line of (parietal) pleural reflection

Costochondral junction Right crus of diaphragm

3.25

Left crus of diaphragm

10th rib

TOPOGRAPHY OF THE LUNGS AND MEDIASTINUM

• The m ediastinum is located between the p leural cavities and is occupied by the heart and the tissues anterior, posterior, and sup erior to the heart. • The apex of the lungs is at the level of the neck of the 1st rib, and the inferior border of the lungs is at the 6th rib in the left m idclavicular line and the 8th rib at the lateral aspect of the bony thorax at the m idaxillary line. • The cardiac notch of the left lung and the corresp onding deviation of the parietal pleura are away from the m edian plane toward the left side.

• The inferior re ection of parietal pleura is at the 8th costochondral junction in the m idclavicular line, at the 10th rib in the m idaxillary line. • The apex of the heart is in the 5th intercostal space at the left m idclavicular line. • The right atrium form s the right border of the heart and extends just beyond the lateral m argin of the sternum . • The branches of the great vessels pass through the superior thoracic aperture.

THORACIC CONTENTS

Th o rax

219

1st rib Clavicle Trachea

Medial border scapula Arch of aorta Pulmonary vessels Left auricle

Right atrium Left ventricle Diaphragm Descending aorta Air in fundus of stomach

Right costodiaphragmatic recess (costophrenic sulcus)

Right costodiaphragmatic recess (costophrenic sulcus)

A. Postero-anterior View

RADIOGRAPH OF CHEST

Lung Trachea Hilum of lungs

Heart Thoracic vertebrae Intervertebral foramen Domes of diaphragm Left and right costodiaphragmatic recess (costophrenic sulcus)

B. Lateral View

3.26

A. Posterior-anterior (PA) radiograph. • Unless a patient is bedridden, a chest radiograph is done with the x-ray beam traversing the patient from posterior to anterior (PA) because this minimizes distortion. The scapula is protracted and not in the main eld of view. • Right atrium is the prim ary discernible structure along the right border of the heart. • Within the dark gray (radiolucent) regions of both sides that show air in the lung, m ost of the linear denser (whiter) elem ents are pulm onary veins. • Along the up per left m ediastinal border, the arch of aorta visible, and the aorta can be followed inferiorly. • Left auricle is often visible along the left border of the heart; inferiorly is the border of the left ventricle. • In a standing PA radiograph, air is often seen in the fund us of the stom ach. B. Lateral rad iograph. • Note that the left and right are not p recisely superim p osed on one another. • Notice how well the heart is shown relative to the aerated lungs, which are radio-opaque because they do not block many photons. A loss of this clear differentiation is known as the silhouette sign and suggests lung disease. • Any structure in the mediastinum m ay contribute to p ath olog ical wid en in g of th e m ed iastin al silh ouette (e.g., after trauma that produces hem orrhage into the mediastinum ), m alignant lymphoma (cancer of lymphatic tissue) that produces m assive enlargement of m ediastinal lym ph nodes, or enlargement (hypertrophy) of the heart occurring with congestive heart failure.

Th o rax

220

PLEURAL CAVITIES

Trachea Nasal cavity

Pharyngeal opening of pharyngotympanic tube

Palate Tongue Epiglottis

Pleural cavity

Air

Nasal part Pharynx

Oral part Laryngeal part

Larynx Trachea

Cervical part

Bronchial tree

Pleural cavity

*Costal

COLLAPSED LUNG

part

Costal pleura

Costal surface of left lung covered with visceral pleura

Pleural cavity

B. Anterior View Parietal pleura parts*

Pleura

Cardiac notch

Visceral pleura

INFLATED LUNG

Cervical Costal Diaphragmatic Mediastinal

Visceral Parietal

*Mediastinal part

Lingula

*Diaphragmatic part Costodiaphragmatic recess

A. Anterior View

3.27

*Parts of parietal pleura

Trachea Apex of left lung

RESPIRATORY SYSTEM AND PLEURA

A. Overview. B. Pleural cavity and pleura. C. Diagrammatic section through heart and lungs with pulmonary vessels and tracheobronchial tree. • The lungs invaginate a continuous m em branous pleural sac; the visceral (pulm onary) pleura covers the lungs, and the parietal pleura lines the thoracic cavity; the visceral and parietal pleurae are continuous around the root of the lung. • The p arietal p leura can be divided regionally into the costal, diaphragm atic, m ediastinal, and cervical parts; note the costodiaphragm atic recess. • The pleural cavity is a potential space between the visceral and parietal pleurae that contains a thin layer of uid. If a suf cient amount of air enters the pleural cavity, the surface tension adhering visceral to parietal pleura (lung to thoracic wall) is broken, and the lung collapses (atelectasis) because of its inherent elasticity (elastic recoil). When a lung collapses, the pleural cavity—normally a potential space— becomes a real space (B) and may contain air (p neum oth orax), blood (hem othorax), etc.

Superior lobe Structures comprimising root of lung (enter/exit lung at hilum)

Superior lobe

Hilum of lung

Endothoracic fascia

Middle lobe

Middle mediastinum

Cardiac notch

Inferior lobe Inferior lobe Diaphragm Costodiaphragmatic recess

C. Anterior View

Pleural cavity

Th o rax

MEDIASTINUM

221

1st rib Superior mediastinum

T2 T3

Heart

Manubrium

T4

Sternal angle

T5 Pericardial cavity T6

Posterior mediastinum

Anterior mediastinum

T7

T9

Pericardium Fibrous pericardium Serous pericardium: Parietal layer of serous pericardium (lines fibrous pericardium) Visceral layer of serous pericardium (outermost layer of heart wall) Thin film of fluid in pericardial cavity between visceral and parietal layers allows the heart to move freely within the pericardial sac. Pleurae Heart Epicardium (visceral layer Visceral of serous pericardium) Parietal: Myocardium Mediastinal Endocardium Costal

Middle mediastinum

Mediastinum Superior Inferior: Anterior Middle Posterior Transverse thoracic plane

T10 Xiphoid process

Diaphragm

T11 T12

A.

Lateral View

Sternum

Brachiocephalic trunk

Trachea Esophagus

Left brachiocephalic vein

Pulmonary artery

Left lung

Transverse pericardial sinus Oblique pericardial sinus

Schematic Lateral Views

Key for C and D

T8

Key for A

B.

Right ventricle

Right atrium

Pericardial cavity

Arch of aorta Pleural cavity

Left ventricle

Right atrium

Pleural cavity Oblique pericardial sinus

Left atrium

Aortic valve

Left atrium

Costomediastinal recess

Sternum

Left lung

Right lung

T7 Pericardial cavity Central tendon of diaphragm

C. Median Section

MEDIASTINUM AND PERICARDIUM A. Subdivisions of m ediastinum . B. Develop m ent of p ericardial cavity. The em bryonic heart invaginates the wall of the serous sac (left) and soon practically obliterates the pericardial cavity, leaving only a potential sp ace between the layers of serous pericardium (right). C. and D. Layers of p ericardium and heart in sectional views.

Right pulmonary vein

Azygos vein

Left pulmonary vein Esophagus

Thoracic duct

Aorta

D. Transverse Section

3.28 Card iac t am p o n ad e (heart com p ression) is a potentially lethal condition because heart volum e is increasingly com p rom ised by the uid outside the heart but inside the p ericardial cavity. The heart is increasingly com pressed and circulation fails. Blood in the p ericardial cavity, h e m o p e ricard ium , p roduces cardiac tam ponade.

222

Th o rax

LUNGS AND PLEURA

Ribs:

1 2 3 4 5 6 7 8 9 10 Midclavicular lines

A. Anterior View Vertebrae:

T1

3.29

EXTENT OF PARIETAL PLEURA AND LUNGS

Auscult at io n o f lun g s. Note the position of the ssures in relation to overlying ribs. To auscultate the upper lobes, place the stethoscope on the anterior thoracic wall superior to the 4th rib on the right and 6th rib on the left; for the m iddle lobe, place it m edial to the right nipple; for the inferior lobes, place it on the posterior thoracic wall below the 3rd rib.

T12

B. Posterior View

LUNGS AND PLEURA

Ribs:

Th o rax

223

Parts of parietal pleura: Cervical

1 2 Mediastinal

3

Costal

4 5

Costal

6 7

Pulmonary (or lung) cavity

8 Diaphragmatic

9

12

10 11

C. Right Lateral View

D. Left Lateral View (Lung Removed)

3.29

EXTENT OF PARIETAL PLEURA AND LUNGS (continued ) TABLE 3.3

SURFACE MARKINGS OF PARIETAL PLEURA ( BLUE)

Level

Left Pleura

Right Pleura

Apex

About 4 cm superior to middle of clavicle

About 4 cm superior to middle of clavicle

4th costal cartilage

Midline (anteriorly)

Midline (anteriorly)

6th costal cartilage

Lateral margin of sternum

Midline (anteriorly)

8th costal cartilage

Midclavicular line

Midclavicular line

10th rib

Midaxillary line

Midaxillary line

11th rib

Line of inferior angle of scapula

Line of inferior angle of scapula

12th rib

Lateral border of erector spinae to T12 spinous process (slightly lower level than right pleura)

Lateral border of erector spinae to T12 spinous process

SURFACE MARKINGS OF LUNGS COVERED WITH VISCERAL PLEURA ( PINK) Level

Left Lung

Right Lung

Apex

About 4 cm superior to middle of clavicle

About 4 cm superior to middle of clavicle

2nd costal cartilage

Midline (anteriorly)

Midline (anteriorly)

4th costal cartilage

Leaves lateral margin of sternum, follows 4th costal cartilage

Lateral margin of sternum

6th costal cartilage

Turns inferiorly to 6th costal cartilage in the midclavicular line (cardiac notch)

Follows 6th costal cartilage to midclavicular line

8th rib

Midaxillary line

Midaxillary line

10th rib

Line of inferior angle of scapula to T10 spinous process

Line of inferior angle of scapula to T10 spinous process

224

Th o rax

LUNGS AND PLEURA

Apex

Superior lobe Anterior border

Oblique fissure

Neck of 1st rib Apex

Horizontal fissure

Sternum Superior lobe

Middle lobe Oblique fissure Inferior lobe

Horizontal fissure Middle lobe Inferior lobe Right dome of diaphragm 6th rib

B. Lateral View

8th rib Costal part of diaphragm

Superior lobe

Oblique fissure

A. Lateral View

Posterior border

Middle lobe

3.30

RIGHT LUNG

• The obliq ue and horizontal ssures divid e the right lung into three lobes: sup erior, m iddle, and inferior. • The right lung is larger and heavier than the left but is shorter and wider because the right dom e of the diaphragm is higher and the heart bulges m ore to the left. • Cadaveric lungs m ay be shrunken, rm , and discolored, whereas healthy lungs in living p eople are norm ally soft, light, and spongy. • Each lung has an apex and base, three surfaces (costal, m ediastinal, and diap hragm atic), and three borders (anterior, inferior, and posterior).

Inferior lobe

C. Posterior View

LUNGS AND PLEURA

Th o rax

225

Apex

Anterior border

Superior lobe

Oblique fissure Apex Neck of 1st rib Sternum Inferior lobe

Superior lobe Oblique fissure Inferior lobe

Cardiac notch Cardiac notch

Lingula

Left dome of diaphragm Lingula

B. Lateral View

6th rib 8th rib Costal part of diaphragm Superior lobe

Oblique fissure

A. Lateral View

Inferior lobe Posterior border

LEFT LUNG

C. Posterior View

3.31

• The left lung has two lobes, superior and inferior, separated by the oblique ssure. • The anterior border has a deep cardiac notch that indents the antero-inferior aspect of the superior lobe. • The lingula, a tonguelike process of the superior lobe, extends below the cardiac notch and slides in and out of the costom ediastinal recess during inspiration and expiration. • The lungs of an em balm ed cadaver usually retain im pressions of structures that lie adjacent to them , such as the ribs and heart.

Th o rax

226

LUNGS AND PLEURA

Apex

Tracheal area

Esophageal area

Groove for brachiocephalic vein

Groove for arch of azygos vein

Groove for 1st rib

Oblique fissure

Pleural sleeve Right main bronchus dividing into superior lobar and intermediate bronchus

Groove for superior vena cava

Pulmonary artery Bronchial vessels Cardiac impression

Pulmonary vein

Anterior border Groove for esophagus Horizontal fissure Pulmonary ligament

Middle lobe

Groove for inferior vena cava

Oblique fissure

Diaphragmatic surface

Medial View Inferior border

3.32

MEDIASTINAL (MEDIAL) SURFACE AND HILUM OF RIGHT LUNG

Th e em b alm ed lung shows im p ressions of the structures with which it com es in to contact, clearly d em arcated as surface features; th e b ase is contoured b y the d om es of th e d iap hrag m ;

the costal surface b ears the im p ressions of the rib s; d istend ed vessels leave their m ark, b ut nerves d o not. The ob liq ue ssure is incom p lete here.

Th o rax

LUNGS AND PLEURA

227

Apex

Area for trachea and esophagus

Groove for left subclavian artery

Groove for arch of aorta

Groove for 1st rib

Oblique fissure

Pleural sleeve Pulmonary artery Bronchopulmonary (hilar) lymph node

Bronchial artery Left main bronchus

Anterior border Pulmonary veins

Cardiac impression Groove for descending aorta

Pulmonary ligament Cardiac notch Area for esophagus Lingula

Diaphragmatic surface

Oblique fissure

Inferior border Medial View

MEDIASTINAL (MEDIAL) SURFACE AND HILUM OF LEFT LUNG Note the site of contact with esophagus, between the descending aorta and the inferior end of the pulm onary ligam ent. In the right and left roots, the artery is superior, the bronchus is posterior,

3.33

one vein is anterior, and the other is inferior; in the right root, the bronchus to the superior lobe (eparterial bronchus) is the m ost superior structure.

Th o rax

228

BRONCHI AND BRONCHOPULMONARY SEGMENTS

RIGHT

LEFT

Apical Posterior Apical Superior lobe

Anterior Superior lobe

Posterior Anterior

Middle lobe

Superior lingular Inferior lingular Superior

Lateral Medial Superior

Anterior basal Anteromedial Inferior lobe Medial basal basal

Anterior basal Inferior lobe

Medial basal Lateral basal

A. Anterior View

RIGHT LUNG

Lateral basal

Posterior basal

Posterior basal

LEFT LUNG

B. Anterior View

3.34

Apicoposterior

LEFT LUNG

RIGHT LUNG

C. Posterior View

SEGMENTAL BRONCHI AND BRONCHOPULMONARY SEGMENTS

A. There are 10 right tertiary or segm ental bronchi and 8 left. Note that in the left lung, the apical and p osterior bronchi arise from a single stem , as do the anterior basal and m edial basal. B–F. A bronchopulm onary segm ent consists of a tertiary bronchus, pulm onary vein and artery, and the portion of lung they serve. These

structures are surgically separable to allow segm ental resection of the lung. To prepare these specim ens, the tertiary bronchi of fresh lungs were isolated within the hilum and injected with latex of various colors. Minor variations in the branching of the bronchi result in variations in the surface p atterns.

BRONCHI AND BRONCHOPULMONARY SEGMENTS

Th o rax

229

RIGHT LUNG

Anterior

Medial Lateral

Posterior Lateral View

Medial View

Inferior View

LEFT LUNG

Anterior

Lateral

Medial

Posterior

D. Lateral View

F. Inferior View

E. Medial View

SEGMENTAL BRONCHI AND BRONCHOPULMONARY SEGMENTS (continued ) Knowledge of the anatomy of the bronchopulmonary segments is essential for precise interpretations of diagnostic images of the lungs and for surgical resection (removal) of diseased segments. During the treatment of lung cancer, the surgeon may remove a whole lung (p n eum on ectom y), a lobe (lob ectom y), or one or more

3.34

bronchopulmonary segments (seg m en tectom y). Knowledge and understanding of the bronchopulmonary segments and their relationship to the bronchial tree are also essential for planning drainage and clearance techniques used in physical therapy for enhancing drainage from speci c areas (e.g., in patients with pneumonia or cystic brosis).

230

Th o rax

BRONCHI AND BRONCHOPULMONARY SEGMENTS

Trachea

Left main bronchus

Right main bronchus

Left superior lobar bronchus

Right superior lobar bronchus Intermediate bronchus

Left inferior lobar bronchus

Right middle lobar bronchus

Right lower lobar bronchus

Carina

Anterior View

Segmental bronchi RIGHT LUNG

3.35

TRACHEA AND BRONCHI IN SITU

• The segm ental (tertiary) bronchi are color-coded. • The trachea bifurcates into right and left m ain (prim ary) bronchi; the right m ain bronchus is shorter, wider, and m ore vertical than the left. • Therefore, it is m ore likely that asp irat e d fo re ig n b o d ie s will enter and lodge in the right m ain bronchus or one of its descend ing branches. • The right m ain bronchus g ives off the right sup erior lobe bronchus (eparterial bronchus) before entering the hilum (hilus) of the lung; after entering the hilum , the continuing interm ediate bronchus d ivides into the right m iddle and inferior lobar b ronchi. • The left m ain bronchus divides at the hilum into the left superior and left inferior lobar bronchi; the lobar bronchi further divide into segm ental (tertiary) bronchi.

LEFT LUNG

Superior Lobe

Superior Lobe

Apical

Apical

Posterior

Posterior

Anterior

Anterior

Middle Lobe Lateral Medial Inferior Lobe Superior

Apicoposterior

Superior lingular Inferior lingular Inferior Lobe Superior Anterior basal

Anterior basal

Medial basal

Medial basal

Lateral basal

Lateral basal

Posterior basal

Posterior basal

Anteromedial basal

BRONCHI AND BRONCHOPULMONARY SEGMENTS

Th o rax

231

Apex of right lung

Trachea

Right main bronchus Carina Right upper lobe bronchus Left main bronchus Left upper lobe bronchus Right middle lobe bronchus Left lower lobe bronchus Right lower lobe bronchus

Tertiary bronchi

Tertiary bronchi

A. CT 3D Airway Study

Carina Carina

Right main bronchus

Left main bronchus

Entire trachea and carina

Carina

Segmental bronchi

B. Bronchoscopic Views

Right upper lobe bronchus

IMAGING OF LUNGS

3.36

A. Norm al CT 3D airway study. CT im aging data can be reform atted to dem onstrate speci c anatom ical structures as shown here for the bronchi. B. Bronchoscopy. When exam ining the bronchi with a b ro n ch o sco p e —an endoscope for inspecting the interior of the tracheobronchial tree for diagnostic purposes—one can observe a ridge, the carina, between the ori ces of the m ain bronchi. If the tracheobronchial lym ph nodes in the angle between the m ain bronchi are enlarged (e.g., because cancer cells have m etastasized from a b ro n ch o g e n ic carcin o m a) the carina is distorted, widened posteriorly, and im m obile.

232

Th o rax

BRONCHI AND BRONCHOPULMONARY SEGMENTS

Trachea

Right main bronchus

Right superior lobe bronchus Stenotic left main bronchus

Intermediate bronchus

C. 3D Airway Study Showing Airway Stenosis

Trachea

Right superior lobe bronchus Left main bronchus Intermediate bronchus

Left superior lobe bronchus Left inferior lobe bronchus

Dilated bronchi Dilated bronchi

Minimum intensity projection (MinIP) is used to visualize low-density structures within a given volume.

D. CT Minimum Intensity Projection (MinIP) Showing Bronchiectasis

3.36

IMAGING OF LUNGS (continued )

C. St e n o t ic m ain b ro n ch i. This patient com plained of dif culty breathing. A stent was inserted into the bronchus to widen it. D. CT MinIP is used to reveal abnorm ally dilated bronchi, a condi-

tion called b ro n ch ie ct asis. The abnorm al dilation of these bronchi interferes with m ucous rem oval and is associated with repeated pulm onary infections.

Th o rax

BRONCHI AND BRONCHOPULMONARY SEGMENTS

233

Medial Views Posterior1

Apical1

Apical1

Posterior1

Right pulmonary artery

Apicoposterior1 Left main bronchus

Right main bronchus

Anterior1

Anterior1 Superior3

Superior lingular1

Superior3 Inferior lingular1 Lateral2 Anteromedial basal3 Posterior basal3 Medial2

Posterior basal3

Medial basal3 Lateral basal3 Anterior basal3

Lateral basal3 B. Left Lung

A. Right Lung

Medial basal3

Anterior basal3

Trachea Right pulmonary artery

Left main bronchus Left pulmonary artery

Right main bronchus

PT

Right superior lobar bronchus

SVC Left superior lobar bronchus

Middle lobar bronchus Pulmonary trunk Right inferior lobar bronchus

Azygos vein

Aorta

LPA

RPA

LSPV

Left inferior lobar bronchus

RSPV LA LIPV

Intermediate bronchus

RIPV

C. Anterior View

RELATIONSHIP OF BRONCHI AND PULMONARY ARTERIES

3.37

A. Right lung. B. Left lung. C. Pulm onary arteries and m ain bronchi. Superscripts indicate segm ental bronchi to the 1 superior lobe, 2 m iddle lobe, and 3 inferior lobe. The pulm onary arteries of fresh lungs were lled with latex; the bronchi were in ated with air. The tissues surrounding the bronchi and vessels were rem oved . Obstruction of a p ulm onary artery by a blood clot (p ulm o n ary e m b o lism ) results in p artial or com plete obstruction of blood ow to the lung.

Posterior View

3D VOLUME RECONSTRUCTION (3DVR) OF PULMONARY ARTERIES AND VEINS AND LEFT ATRIUM

3.38

The p ulm onary trunk (PT) divides into a longer right p ulm onary artery (RPA) and shorter left pulm onary artery (LPA); the left superior (LSPV) and inferior (LIPV) and the right superior (RSPV) and inferior (RIPV) pulm onary veins drain into the left atrium (LA). SVC, superior vena cava.

234

Th o rax

INNERVATION AND LYMPHATIC DRAINAGE OF LUNGS

Right vagus nerve Right phrenic nerve

Left vagus nerve Left phrenic nerve Cervical cardiac branches (vagosympathetic)

Right recurrent laryngeal nerve Left recurrent laryngeal nerve

Pulmonary plexus Pulmonary trunk Left vagus nerve

Right vagus nerve

Anterior View

3.39

Esophageal plexus

INNERVATION OF LUNGS

• The pulm onary plexuses, located anterior and posterior to the roots of the lungs, receive sym p athetic contributions from the right and left sym pathetic trunks (2nd to 5th thoracic ganglia, not shown) and p arasym pathetic contributions from the right and left vagus nerves; cell bodies of postsynaptic parasym pathetic neurons are in the pulm onary plexuses and along the branches of the pulm onary tree. • The right and left vagus nerves continue inferiorly from the posterior pulm onary plexus to contribute bers to the esophageal plexus.

• The phrenic nerves pass anterior to the root of the lung on their way to the diaphragm . • Visceral pleura is insensitive to pain. The autonom ic nerves reach the visceral pleura in com pany with the bronchial vessels. The visceral pleura receives no nerves of general sensation. • Parietal pleura is richly supplied by branches of the somatic intercostal and phrenic nerves. Irritation of the parietal pleura p leuritus produces local pain p leurisy and referred pain to the areas sharing innervation by the same segments of the spinal cord.

Th o rax

INNERVATION AND LYMPHATIC DRAINAGE OF LUNGS

Trachea

235

Esophagus Tracheal (paratracheal) node

Inferior deep cervical (scalene) node

Left internal jugular vein

Right internal jugular vein

Inferior deep cervical (scalene) node Left jugular lymphatic trunk

Right lymphatic duct

Supraclavicular nodes

Supraclavicular nodes

Left subclavian lymphatic trunk

Right subclavian lymphatic trunk

Thoracic duct

Right subclavian vein

Left subclavian vein

Right bronchomediastinal trunk

Left bronchomediastinal trunk

Superior tracheobronchial node

Aortic arch node Inferior tracheobronchial (carinal) node

Bronchopulmonary (hilar) nodes

Bronchopulmonary (hilar) nodes

Pulmonary (intrapulmonary) nodes

Subpleural lymphatic plexus

Pulmonary nodes

Interlobular lymphatic vessels

Anterior View Drainage from deep lymphatic plexus

LYMPHATIC DRAINAGE OF LUNGS • Lym phatic vessels originate in the subp leural (sup er cial) and deep lym phatic plexuses. • The subp leural lym p hatic p lexus is super cial, lying deep to the visceral pleura, and drains lym ph from the surface of the lung to the bronchopulm onary (hilar) nodes. • The deep lym p hatic p lexus is in the lung and follows the bronchi and pulm onary vessels to the pulm onary, and then bronchopulm onary, nodes located at the root of the lung. • All lym p h from the lungs enters the inferior (carinal) and superior tracheobronchial nodes and then continues to the right and left bronchom ediastinal trunks to drain into the venous system via the right lym phatic and thoracic ducts; lym ph from the left inferior lobe p asses largely to the right side. • Lym ph from the parietal p leura drains into lym p h nodes of the thoracic wall (Fig. 3.71).

3.40 Lun g can ce r (carcin o m a) m etastasizes early to the bronchopulm onary lym ph nodes and subsequently to the other thoracic lym ph nodes. Com m on sites of h e m at o g e n o us m e t ast ase s (sp reading through the blood ) of cancer cells from a bronchogenic carcinom a are the brain, bones, lungs, and suprarenal glands. Often the lym p h nodes superior to the clavicle—the sup raclavicular lym ph nodes—are enlarg ed when lung (b ronchogenic) carcinom a develop s owing to m etastasis of cancer cells from the tum or. Consequently, the supraclavicular nodes were once referred to as sentinel lym p h nodes. More recently, the term sentinel lym ph node has been applied to a node or nodes that rst receive lym ph drainage from a cancer-containing area, regardless of location, following injection of blue dye containing radioactive tracer (technetium -99).

236

Th o rax

EXTERNAL HEART

Intercostal spaces:

Ribs:

1 1 2 2

A

P 3

3 4 4 T 5

M

5 6

6 7 7 8 9

8 9 10

Key T M P A

Tricuspid valve Mitral valve Pulmonary valve Aortic valve

Anterior View

3.41

SURFACE PROJECTIONS OF THE HEART, HEART VALVES, AND THEIR AUSCULTATION AREAS

• The location of each heart valve in situ is indicated by a colored oval and the area of auscultation of the valve is indicated as a circle of the sam e color containing the rst letter of the valve nam e. • The auscult at io n are as are sites where the sounds of each of the heart’s valves can be heard m ost distinctly through a stethoscop e (card iac auscult at io n ).

• The aortic (A) and pulm onary (P) auscultation areas are in the 2nd intercostal space to the right and left of the sternal border; the tricuspid area (T) is near the left sternal border in the 5th or 6th intercostal sp ace; the m itral valve (M) is heard best near the ap ex of the heart in the 5th intercostal space in the m idclavicular line.

Th o rax

EXTERNAL HEART

237

Ribs/Costal cartilages:

1 2 3 4

3

5

6

8

2

4

5

7

1

6 7

8

9 9 10 10

Key Heart Lungs Parietal pleura Diaphragm

Anterior View

SURFACE MARKINGS OF THE HEART, LUNGS, AND DIAPHRAGM • The superior border of the heart is represented by a slightly oblique line joining the 3rd costal cartilages; the convex right side of the heart projects lateral to the sternum and inferiorly, lying at the 6th or 7th costochondral junction; the inferior border of the heart is lying superior to the central tendon of the diaphragm and sloping slightly inferiorly to the apex at the 5th interspace at the midclavicular line.

3.42

• The right dom e of the diaphragm is higher than the left because of the larg e size of the liver inferior to the dom e; during exp iration, the right dom e reaches as high as the 5th rib and the left dom e ascends to the 5th intercostal space. • The left pleural cavity is sm aller than the right because of the projection of the heart to the left side.

238

Th o rax

EXTERNAL HEART

Left common carotid artery Left subclavian artery Brachiocephalic trunk

Left brachiocephalic vein

Right brachiocephalic vein

Arch of aorta Ligamentum arteriosum

Superior vena cava (1) Left pulmonary artery Pulmonary trunk (13)

Right pulmonary arteries

Superior Inferior

Ascending aorta (2) Right pulmonary veins

Superior Inferior

Left pulmonary veins

Left coronary artery Left auricle (12)

Right auricle (3)

Circumflex branch (11)

Right coronary artery (4)

Great cardiac vein

Anterior cardiac veins

Left marginal artery

Right border of heart

Anterior interventricular artery (10)

Right atrium (5) Coronary (atrioventricular) sulcus (6)

Left ventricle (9)

Right ventricle (7) Right marginal artery Left border of heart

Small cardiac vein Inferior vena cava (8)

Apex of heart

A. Anterior View

Inferior border of heart

From upper body

To head and upper limbs

Key for C Deoxygenated blood Oxygenated blood

2

1

12 3

4

9 7

To left lung via left pulmonary artery Left atrium

To right lung via right pulmonary artery Superior vena cava From right lung via right pulmonary veins

11

10

6 5

Aorta

Pulmonary trunk

13

From left lung via left pulmonary veins

Pulmonary valve

Mitral valve Left ventricle

Right atrium

4

Aortic valve Right ventricle

8

Tricuspid valve

Inferior vena cava

B. Anterior View

3.43

HEART AND GREAT VESSELS

C. Schematic

Coronal Section

Descending aorta From lower trunk and limbs

To lower trunk and limbs

Th o rax

EXTERNAL HEART

239

Left common carotid artery Left subclavian artery Arch of aorta

Ligamentum arteriosum Left pulmonary artery (1)

Brachiocephalic trunk

Arch of azygos vein Superior vena cava Right pulmonary artery (15)

Left pulmonary Superior (2) veins Inferior (3) Left auricle (4)

Superior (14) Inferior (13)

Right pulmonary veins

Left atrium (5) Right atrium (12)

Great cardiac vein

Coronary sinus (11)

Circumflex branch (6)

Inferior vena cava

Oblique vein of left atrium

Small cardiac vein Left posterior ventricular vein Right coronary artery (10) Middle cardiac vein (9) Posterior interventricular artery (8)

Left ventricle (7)

Right ventricle

Anterior interventricular artery

D. Postero-inferior View

15 1 14

2

HEART AND GREAT VESSELS (continued )

13

3 5 4

12

11 6 7 9 8

E. Postero-inferior View

10

3.43

A. Anatom ical specim en. • The right border of the heart, form ed by the right atrium , is slightly convex and alm ost in line with the superior vena cava. • The inferior border is form ed p rim arily by the right ventricle and part of the left ventricle. • The left border is form ed p rim arily by the left ventricle and part of the left auricle. B. 3D volum e reconstruction from MRI of heart and coronary vessels (living patient). Num b ers refer to structures ( A) . C. Circulation of blood throug h the heart. D. Anatom ical specim en, posterior view. • Most of the left atrium and left ventricle are visib le in this postero-inferior view. • The right and left p ulm onary veins open into the left atrium . • The arch of the aorta extend s superiorly, p osteriorly and to the left, in a nearly sagittal plane. E. 3D volum e reconstruction from MRI of heart and coronary vessels. Num bers refer to structures ( D) .

Th o rax

240

EXTERNAL HEART

Right vagus nerve

Right common carotid artery

Trachea

Right internal jugular vein Right phrenic nerve

Left common carotid artery Left vagus nerve Left internal jugular vein Left phrenic nerve

Right subclavian vein Left subclavian vein Brachiocephalic trunk Left brachiocephalic vein Right brachiocephalic vein Manubrium Right phrenic nerve

Internal thoracic artery

Superior vena cava

Sternal angle at manubriosternal joint (divided)

2nd costal cartilage Root of lung Internal thoracic artery

Left phrenic nerve

Right lung

Left lung

Right phrenic nerve

Pericardium

Body of sternum Right dome of diaphragm Left dome of diaphragm Left phrenic nerve

Xiphisternal joint 7th costal cartilage Xiphoid process Anterior View

3.44

PERICARDIUM IN RELATION TO STERNUM

• The pericardium lies p osterior to the b ody of the sternum , extending from just superior to the sternal angle to the level of the xiphisternal joint; approxim ately two thirds lies to the left of the m edian plane. • The heart lies b etween the sternum and the anterior m ediastinum anteriorly and the vertebral colum n and the posterior m ediastinum p osteriorly.

• In card iac co m p re ssio n , the sternum is dep ressed 4 to 5 cm , forcing blood out of the heart and into the great vessels. • Internal thoracic arteries arise from the subclavian arteries and descend posterior to the costal cartilages, running lateral to the sternum and anterior to the pleura.

Th o rax

EXTERNAL HEART

Inferior cervical cardiac nerve (sympathetic: from cervicothoracic [stellate] ganglion)

Brachiocephalic trunk

241

Left common carotid artery Left vagus nerve Left subclavian artery

Right brachiocephalic vein

Inferior cervical cardiac branch (CN X) Arch of aorta Left recurrent laryngeal nerve

Arch of azygos vein

Ligamentum arteriosum Superior vena cava

Left pulmonary artery Anterior pulmonary plexus

Ascending aorta

Left superior pulmonary vein

Pericardium (cut edge)

Pulmonary trunk

Right superior pulmonary vein

Arrow traversing transverse pericardial sinus

Arrow traversing transverse pericardial sinus

Left auricle

Right auricle

Anterior interventricular branch of left coronary artery (left anterior descending branch)

Sulcus terminalis (terminal groove) Right coronary artery

Great cardiac vein

Right atrium Right ventricle Anterior cardiac vein Marginal artery Left ventricle Pericardium (cut edge)

Diaphragm Anterior View

STERNOCOSTAL (ANTERIOR) SURFACE OF HEART AND GREAT VESSELS IN SITU • The right ventricle form s m ost of the sternocostal surface. • The entire right auricle and m uch of the right atrium are visible anteriorly, but only a sm all portion of the left auricle is visible; the auricles, like a closing claw, grasp the origins of the pulm onary trunk and ascending aorta from a p osterior app roach. • The lig am entum arteriosum p asses from the origin of the left pulm onary artery to the arch of the aorta. • The right coronary artery courses in the anterior atrioventricular groove, and the anterior interventricular branch of the left

3.45

coronary artery (anterior descending branch) courses in or p arallel to the anterior interventricular groove (see Fig. 3.43B). • The left vagus nerve passes lateral to the arch of the aorta and then posterior to the root of the lung; the left recurrent laryngeal nerve passes inferior to the arch of the aorta posterior to the ligam entum arteriosum . • The great cardiac vein ascends beside the anterior interventricular branch of the left coronary artery to drain into the coronary sinus p osteriorly.

242

Th o rax

EXTERNAL HEART

Aorta

Pulmonary trunk

Superior vena cava

Arrow traversing transverse pericardial sinus Oblique vein of left atrium

Right pulmonary veins entering the left atrium

Left pulmonary veins entering the left atrium

Right atrium

Great cardiac vein Interatrial sulcus

Visceral layer of serous pericardium

Anterior wall of oblique pericardial sinus

Circumflex branch of left coronary artery

Base (posterior surface) of heart

Inferior vena cava Left ventricle

Right coronary artery Small cardiac vein Coronary sinus (deep to visceral layer of serous pericardium)

Middle cardiac vein

Right ventricle

A. Posterior View

3.46

Posterior interventricular branch

Diaphragmatic surface

HEART AND PERICARDIUM

• This heart ( A) was rem oved from the interior of the pericardial sac ( B) . • The entire base, or p osterior surface, and part of the diap hragm atic or inferior surface of the heart are in view (inset). • The superior vena cava and larger inferior vena cava join the superior and inferior asp ects of the right atrium . • The left atrium form s the greater part of the b ase (posterior surface) of the heart (inset). • The left coronary artery in this specim en is dom inant, since it supp lies the posterior interventricular branch. • Most branches of cardiac veins cross branches of the coronary arteries super cially. • The visceral layer of serous pericardium (epicardium ) covers the surface of the heart and re ects onto the great vessels; from around the great vessels, the serous pericardium re ects to line the internal aspect of the brous pericardium as the parietal

layer of serous pericardium . The brous pericardium and the parietal layer of serous p ericardium form the pericardial sac that encases the heart. • Note the cut edges of the re ections of serous pericardia around the arterial vessels (the pulm onary trunk and aorta) and venous vessels (the superior and inferior venae cavae and the pulm onary veins). • Surg ical iso lat io n o f card iac o ut o w. The transverse p ericardial sinus is especially im portant to cardiac surgeons. After the pericardial sac has been opened anteriorly, a nger can be p assed through the transverse pericardial sinus posterior to the aorta and pulm onary trunk. By passing a surgical clam p or placing a ligature around these vessels, inserting the tubes of a coronary bypass m achine, and then tightening the ligature, surgeons can stop or divert the circulation of blood in these large arteries while perform ing cardiac surgery.

EXTERNAL HEART

Th o rax

243

Ascending aorta Ligamentum arteriosum

Pulmonary trunk

Arrow traversing transverse pericardial sinus

Superior vena cava

Right pulmonary veins

Left pulmonary veins

Posterior wall of oblique pericardial sinus Parietal layer of serous pericardium Pericardial sac Inferior vena cava

Fibrous pericardium

B. Anterior View

HEART AND PERICARDIUM (continued ) • Interior of pericardial sac. Eight vessels were severed to excise the heart: superior and inferior venae cavae, four pulm onary veins, and two pulm onary arteries. • The oblique sinus is bounded anteriorly by the visceral layer of serous p ericardium covering the left atrium ( A) , p osteriorly by the parietal layer of serous pericardium lining the brous pericardium , and sup eriorly and laterally by the re ection of serous pericardium around the four pulm onary veins and the sup erior and inferior venae cavae ( B) . • The transverse sinus is bounded anteriorly by the serous p ericardium covering the posterior asp ect of the pulm onary trunk and

3.46 aorta and posteriorly by the visceral pericardium re ecting from the atria ( A) inferiorly and the superior vena cava superiorly on the right. • Blood in the pericardial cavity, h e m o p e ricard ium , p roduces card iac t am p o n ad e . Hem opericardium m ay result from p erforation of a weakened area of the heart m uscle owing to a p revious m yocard ial in farct io n (MI) or heart attack, from bleeding into the pericardial cavity after cardiac operations, or from stab wounds. Heart volum e is increasingly com p rom ised and circulation fails.

244

Th o rax

EXTERNAL HEART

Aorta

Superior vena cava

Pulmonary trunk

Left pulmonary veins Right pulmonary veins

Descending (thoracic) aorta Esophageal arteries Esophagus Right lung Left vagus nerve Esophagus

Left lung

Inferior vena cava

Esophageal plexus

Parietal layer of serous pericardium fused to central tendon of diaphragm Fibrous pericardium

C. Anterior View

3.46

HEART AND PERICARDIUM (continued )

C. Posterior relationships; dissection. The brous and parietal layers of serous pericardium have been rem oved from posterior and lateral to the obliq ue sinus. The esophagus in this specim en is de ected to the right; it usually lies in contact with the aorta, form ing prim ary posterior relationships of the heart. Surg ical e xp o sure o f ve n ae cavae . After ascending through the diaphragm , the entire thoracic part of the inferior vena cava

(IVC) (approxim ately 2 cm ) is enclosed by the pericardium . Consequently, the pericardial sac m ust be opened to expose the term inal part of the IVC. The sam e is true for the term inal part of the superior vena cava (SVC), which is partly inside and partly outside the pericardial sac.

Th o rax

EXTERNAL HEART

Right lung

Ductus arteriosus

Ligamentum arteriosum (obliterated ductus arteriosus)

2

2

8

13 3

10 11

Arrow traverses patent foramen ovale (white circle)

4

8 9

10

5

Right lung

3

10

11

14

12

8

13

Left lung

4

6

245

8 9

*

10

5

Left lung

14

6

12

Ductus venosus Location of oval fossa *(closed foramen ovale)

Ligamentum venosum (obliterated ductus venosus)

Liver

(white asterisk) Liver

1

1 7

7 Umbilical vein Umbilicus

Umbilical arteries

Round ligament of liver (obliterated umbilical vein)

Oxygenated blood Deoxygenated blood

Umbilicus

Bladder

Bladder

Allantois

Median umbilical ligament (urachus) Oxygenated blood Placenta

Medial umbilical ligaments (obliterated umbilical arteries)

B. After Birth

Partially oxygenated blood Deoxygenated blood

Heart and blood vessels

A. Before Birth

1 2 3 4

Abdominal aorta Arch of aorta Ascending aorta Inferior vena cava

PRE- AND POSTNATAL CIRCULATION A. Before birth. B. After birth. At birth, two m ajor changes take place: (1) pulm onary respiration starts and (2) after the um bilical cord is ligated, the um bilical arteries (except the m ost proxim al

5 6 7 8

Left atrium Left ventricle Portal vein Pulmonary arteries

9 10 11 12

Pulmonary trunk Pulmonary veins Right atrium Right ventricle

13 Superior vena cava 14 Thoracic aorta

3.47 part), um bilical vein, and ductus venosus are occluded and becom e the m edial um bilical ligam ent, round ligam ent of liver, and the ligam entum venosum , respectively.

Th o rax

246

CORONARY VESSELS

Arch of aorta

Ascending aorta Sino-atrial (SA) nodal branch Site of SA node Right coronary artery (RCA) in coronary sulcus

Pulmonary trunk

Circumflex branch of LCA Anterior interventricular branch of LCA

Left coronary artery (LCA) Circumflex branch of LCA Anterior interventricular branch of LCA Left marginal artery

Atrioventricular (AV) nodal branch of RCA

LCA

2/3 1/3

AVbundle

AV node AVnodal artery

Anterior

Posterior Posterior interventricular (IV) branch of RCA

Septal branches

Lateral (diagonal) branch of anterior IVbranch

Right marginal branch of RCA

AVbundle branches

Apex of heart Apex of heart

A. Anterior View

Posterior interventricular branch in posterior interventricular groove

C. Arteries of Isolated Interventricular Septum (from Left Side)

3.48 Arch of aorta Left pulmonary artery

Superior vena cava (SVC) Sino-atrial (SA) nodal branch of RCA

Left coronary artery (LCA) Circumflex branch of LCAin coronary sulcus

Right pulmonary veins Right coronary artery (RCA)

Site of AV node

Crux of heart

Atrioventricular nodal branch of RCA

Anterior interventricular branch of LCA

Posterior interventricular branch of RCA Right marginal branch of RCA

B. Postero-inferior View

CORONARY ARTERIES

A. Anterior view. B. Postero-inferior view. C. Arteries of interventricular septum . • In the m ost com m on p attern, the right coronary artery travels in the coronary sulcus to reach the posterior surface of the heart, where it anastom oses with the circum ex branch of the left coronary artery. Early in its course, it gives off the right atrial branch, which supplies the sino-atrial (SA) node via its sino-atrial nodal branch. Major branches are a m arginal branch supplying m uch of the anterior wall of the right ventricle, an atrioventricular (AV) nodal branch given off near the posterior border of the interventricular septum , and a posterior interventricular branch in the interventricular groove that anastom oses with the anterior interventricular branch of the left coronary artery. • The left coronary artery divides into a circum ex branch that passes posteriorly to anastom ose with the right coronary artery on the posterior aspect of the heart and an anterior interventricular branch in the interventricular groove; the origin of the SA nodal branch is variable and m ay be a branch of the left coronary artery. • The interventricular septum receives its blood supply from sep tal branches of the two interventricular (descending) branches: typically the anterior two thirds from the left coronary, and the posterior one third from the right ( C) .

Th o rax

CORONARY VESSELS

247

Oblique vein of left atrium Great cardiac vein Coronary artery

Cardiac vein Fibrous pericardium Parietal layer of serous pericardium

Anterior cardiac veins

Pericardial cavity Visceral layer of serous pericardium (epicardium)

Coronary sinus

Subserous layer (subendocardial fat) Myocardium

Small cardiac vein

Endocardium Smallest cardiac veins (venae cordis minimae)

B

A. Anterior View Middle cardiac vein

LA

Great cardiac vein (4)

4

RA

1

Left marginal vein Oblique vein of left atrium

LV 3

2

Posterior vein of left ventricle

Coronary sinus (1)

RV Small cardiac vein (2) Middle cardiac vein (3)

C. Postero-inferior View

CARDIAC VEINS A. Anterior aspect. B. Sm allest cardiac veins. C. 3D volum e reconstruction. Num bers refer to veins in D. LA, left atrium ; RA, rig ht atrium ; LV, left ventricle; RV, right ventricle. D. Postero-inferior aspect. The coronary sinus is the m ajor venous drainage vessel of the heart; it is located posteriorly in the atrioventricular (coronary) groove and drains into the right atrium . The great, m iddle, and

D. Postero-inferior View

3.49 sm all cardiac veins; the obliq ue vein of the left atrium ; and the posterior vein of the left ventricle are the principal vessels draining into the coronary sinus. The anterior cardiac veins drain directly into the right atrium . The sm allest cardiac veins (venae cordis m inim ae) drain the m yocardium directly into the atria and ventricles ( B) . The cardiac veins accom p any the coronary arteries and their branches.

Th o rax

248

CORONARY VESSELS

Catheter

Sinu-atrial nodal branch Right coronary artery

A B. Left Anterior Oblique View

Posterior interventricular branch (posterior descending artery)

Catheter

Left coronary artery Circumflex branch

Anterior interventricular branch (left anterior descending artery—LAD)

C D. Left Anterior Oblique View

3.50

CORONARY ARTERIOGRAMS WITH ORIENTATION DRAWINGS

Right (A and B) and left (C and D) coronary arteriogram s. Co ro n ary art e ry d ise ase (CAD), one of the lead ing causes of death, results in a reduced blood supply to the vital m yocardial tissue. The three m ost com m on sites of coronary artery occlusion and the ap proxim ate p ercentage of occlusions involving each

artery are the (1) anterior interventricular (clinically referred to as LAD) branch of the left coronary artery (LCA) (40% to 50%), (2) right coronary artery (RCA) (30% to 40%), and (3) circum ex branch of the LCA (15% to 20%).

Th o rax

CORONARY VESSELS

249

Aortic sinus above valve cusp Left coronary artery Right coronary artery Circumflex branch Posterior interventricular branch

AR

Anterior interventricular branch

AA

Level of sections Right marginal artery

C

LCA

C

Anterior View

RCA

Anterior (sternocostal) surface Atrioventricular bundle in interventricular septum Left (L)

Right (R)

A

B. Coronary Angiogram, Anteroposterior View

Inferior View

Key for B

Diaphragmatic (inferior) surface

AA Ascending aorta AR Arch of aorta C Cusp of aortic valve

A. and B. Most common pattern (67%).

Right coronary artery is dominant, giving rise to the posterior interventricular branch.

LCA Left coronary artery RCA Right coronary artery

Myocardium supplied by RCA Myocardium supplied by LCA

Right coronary artery Aortic valve Left coronary artery

C

E

D

R

L

R

L

C. and D. Left coronary artery gives rise to the posterior interventricular branch (15%).

R

L

E. Circumflex Branch Emerging from Right Coronary Sinus.

VARIATIONS IN DISTRIBUTION OF CORONARY ARTERIES A. Most com m on pattern. B. Coronary angiogram of m ost com m on p attern. C–E. Less com m on patterns.

3.51

Th o rax

250

CONDUCTION SYSTEM OF HEART RA

Superior vena cava Sinu-atrial (SA) node

Atrioventricular (AV) node

LA

Sulcus (crista) terminalis

x

Membranous interatrial and interventricular septa LV

Muscular interventricular septum

AVbundle x Right and left bundles

LV

RV

Preferential (physiological) pathways

Anterior papillary muscle Septomarginal trabecula (moderator band)

RV

A

B Anterior Views

3.52

LA

RA

x Crus of heart

CONDUCTION SYSTEM OF HEART, CORONAL SECTION

A. Im pulses (arrows) initiated at the sino-atrial node. B. Atrioventricular (AV) node, AV bundle, and bundle branches. C. Echocardiogram , apical four-cham ber view. • The sino-atrial (SA) node is in the wall of the right atrium near the sup erior end of the sulcus term inalis (internally crista term inalis) at the opening of the superior vena cava. The SA node is the “pacem aker” of the heart because it initiates m uscle contraction and determ ines the heart rate. It is supplied by the sino-atrial nodal artery, usually a branch of the right atrial branch of the right coronary artery, b ut it m ay arise from the left coronary artery. • Contraction spreads through the atrial wall (m yogenic ind uction) until it reaches the AV node in the interatrial septum , sup erom edial to the op ening of the coronary sinus. The AV node is supplied by the AV nodal artery, usually arising from the right coronary artery posteriorly at the inferior m argin of the interatrial septum . • The AV bundle, usually supp lied by the right coronary artery, passes from the AV node in the m em branous part of the interventricular septum , dividing into right and left bundle branches on either side of the m uscular part of the interventricular septum . • The right bundle branch travels inferiorly in the interventricular sep tum to the anterior wall of the ventricle, with part passing via the septom arginal trabecula to the anterior papillary m uscle; excitation spreads throughout the right ventricular wall through a network of subendocardial branches (Purkinje bers) from the right bundle. • The left bundle branch lies beneath the endocardium on the left side of the interventricular septum and branches to enter the anterior and posterior papillary m uscles and the wall of the left ventricle; further branching into a plexus of subendocardial branches allows the im pulses to be conveyed throughout the left ventricular wall. The bundle branches are m ostly supplied by the left coronary artery except the posterior lim b of the left bundle branch, which is supplied by both coronary arteries. • Dam ag e t o t h e card iac co n d uct io n syst e m (often by com p rom ised blood supp ly as in coronary artery disease) leads to disturb ances of m uscle contraction. Dam age to the AV node results in “heart block” because the atrial excitation wave does not reach the ventricles, which begin to contract independently at their own slower rate. Dam age to one of the bundle branches results in “bundle branch block,” in which excitation goes down the unaffected branch to cause systole of that ventricle; the im pulse then sp reads to the other ventricle, prod ucing later asynchronous contraction.

Key for A and B: LA LV RA RV

Left atrium Left ventricle Right atrium Right ventricle

For this ultrasound image, the transducer is usually placed on the chest wall in the left 5th intercostal space and aimed so that the beam obliquely transects the heart and penetrates all four chambers.

Skin

Left

Ventricles

Crux

Atria

C. Echocardiogram. Apical Four-Chamber View

INTERNAL HEART AND VALVES

Th o rax

251

Pulmonary valve (open)

Pulmonary valve (closed)

Aortic valve (open)

Aortic valve (closed) Location of AVbundle Fibrous ring of mitral valve Fibrous ring of tricuspid valve

Mitral valve (open)

Tricuspid valve (open)

A. Diastole

Superior Views

Mitral valve (closed)

B. Systole

Tricuspid valve (closed)

R T

P ECG

Fibrous ring of pulmonary valve

Q S

Fibrous ring of aortic valve

Left fibrous trigone Membranous interatrial septum

Atrial contraction Ventricular pressure Closure of mitral and tricuspid valves Closure of aortic and pulmonary valves Heart sounds

C.

1st

1st

2nd

LUB DUB Systole

Diastole

LUB Systole

CARDIAC CYCLE AND CARDIAC SKELETON A. Ventricular diastole. B. Ventricular systole. C. Correlation of ventricular pressure, electrocardiogram (ECG), and heart sounds. The cardiac cycle describes the com plete movement of the heart or heartbeat and includes the period from the beginning of one heartbeat to the beginning of the next one. The cycle consists of diastole (ventricular relaxation and lling) and systole (ventricular contraction and em ptying). The right heart is the pum p for the pulmonary circuit; the left heart is the pum p for the system ic circuit (see Fig. 3.43C). D. Cardiac skeleton. The brous framework of dense collagen form s four brous rings, which provide attachm ent for the lea ets and cusps of the valves, and two brous trigones that connect the rings, and the mem branous parts of the interatrial and interventricular septa. The brous skeleton keeps the ori ces of the valves patent and separates the m yenterically conducted im pulses of the atria.

Right fibrous trigone

Membranous part of interventricular septum

Tunnel for atrioventricular bundle

Fibrous ring of mitral valve Fibrous ring of tricuspid valve

Membranous atrioventricular septum

D. Postero-inferior View

3.53 Disorders involving the valves of the heart disturb the p um ping ef ciency of the heart. Valvular h e art d ise ase produces either stenosis (narrowing) or insuf ciency. Valvular st e n o sis is the failure of a valve to open fully, slowing blood ow from a cham ber. Valvular in suf cie n cy, or regurgitation, is the failure of the valve to close com pletely, usually owing to nodule form ation on (or scarring and contraction of) the cusps so that the edg es do not m eet or align. This allows a variable am ount of blood (d ep ending on the severity) to ow back into the cham ber it was just ejected from . Both stenosis and insuf ciency result in an increased workload for the heart. Because valvular diseases are m echanical problem s, dam aged or defective cardiac valves are often replaced surgically in a procedure called valvulop last y.

Th o rax

252

INTERNAL HEART AND VALVES

Superior vena cava (SVC)

Sinus venarum (smooth thin part of wall) Opening of coronary sinus (CS)

Pectinate muscles (rough part of wall)

Right atrioventricular orifice

Limbus fossae ovalis (border of oval fossa) Fossa ovalis (oval fossa) Crista terminalis

Valve of coronary sinus Valve of inferior vena cava Inferior vena cava (IVC)

A. Anterior View SVC

CS

Oval fossa

IVC

B. Anterior View

3.54

RIGHT ATRIUM

A. Interior of right atrium . The anterior wall of the right atrium is re ected. B. Blood ow into atrium from the sup erior and inferior venae cavae. • The sm ooth part of the atrial wall is form ed by the absorp tion of the right horn of the sinus venosus, and the rough part is form ed from the p rim itive atrium . • Crista terminalis, the valve of the inferior vena cava, and the valve of the coronary sinus separate the smooth part from the rough part. • The p ectinate m uscle passes anteriorly from the crista term inalis; the crista underlies the sulcus term inalis (not shown), a groove visible externally on the posterolateral surface of the right atrium between the superior and inferior venae cavae. • The superior and inferior venae cavae and the coronary sinus open onto the sm ooth part of the right atrium ; the anterior cardiac veins and venae cordis m inim ae (not visible) also open into the atrium .

• The oor of the fossa ovalis is the rem nant of the fetal septum prim um ; the crescent-shaped ridge (lim bus fossae ovalis) partially surrounding the fossa is the rem nant of the septum secundum . • In ow from the superior vena cava is directed toward the tricuspid ori ce, whereas blood from the inferior vena cava is directed toward the fossa ovalis ( B) . • Congenital anom alies of the interatrial septum , m ost often incom plete closure of the oval foram en (patent foram en ovale), are at rial se p t al d e fe ct s (ASDs). A probe-size patency is present in the superior part of the oval fossa in 15% to 25% of adults (Moore et al., 2012). These sm all openings, by them selves, cause no hem odynam ic abnorm alities. Larg e ASDs allow oxygenated blood from the lungs to be shunted from the left atrium through the ASD into the right atrium , causing enlargem ent of the right atrium and ventricle and dilation of the pulm onary trunk.

Th o rax

INTERNAL HEART AND VALVES

253

Pulmonary trunk Right Anterior Left

Aorta Superior vena cava

Cusps of pulmonary valve Conus arteriosus (infundibulum) Supraventricular crest

Subepicardial fat Septal papillary muscles

Right atrium

Interventricular septum

Tendinous cords

Trabeculae carneae Anterior cusp Of tricuspid valve

Posterior papillary muscle Septomarginal trabecula (moderator band)

Septal cusp Posterior cusp

Anterior papillary muscle

To lungs

A. Anterior View Pulmonary valve Superior vena cava

Conus arteriosus Right ventricle

Inferior vena cava From right atrium via right atrioventricular orifice

B. Anterior View

RIGHT VENTRICLE A. Interior of right ventricle. B. Blood ow throug h right heart. • The entrance to this cham ber, the right atrioventricular or tricusp id ori ce, is situated p osteriorly; the exit, the ori ce of the pulm onary trunk, is sup erior. • The out ow p ortion of the cham ber inferior to the p ulm onary ori ce (conus arteriosus or infundibulum ) has a sm ooth, funnelshap ed wall; the rem ainder of the ventricle is rough with eshy trabeculae. • There are three types of trabeculae: m ere ridg es, bridges attached only at each end, and ngerlike projections called papillary m uscles. The anterior papillary m uscle rises from the anterior wall, the posterior (papillary m uscle) from the posterior wall, and a series of sm all septal papillae from the septal wall.

3.55 • The septom arginal trabecula, here thick, extends from the sep tum to the base of the anterior papillary m uscle. • The m em b ranous p art of the interventricular sep tum d evelop s sep arately from the m uscular p art and has a com p lex em b ryolog ical orig in (Moore et al., 2012). Conseq uently, this p art is the com m on site of ve n t ricula r se p t a l d e fe ct s (VSDs), althoug h d efects also occur in the m uscular p art. VSDs rank rst on all lists of card iac d efects. The size of the d efect varies from 1 to 25 m m . A VSD causes a left-to-rig ht shunt of b lood throug h the d efect. A larg e shunt increases p ulm onary b lood ow, which causes severe p ulm onary d isease (p u lm o n a ry h yp e rt e n sio n , or increased b lood p ressure) and m ay cause ca rd ia c fa ilu re .

Th o rax

254

INTERNAL HEART AND VALVES Right pulmonary veins Left superior pulmonary vein

Superior

Inferior Interatrial septum Left inferior pulmonary vein

Left atrium Fossa ovalis (oval fossa)

Myocardium Left auricle Great cardiac vein

Posterior cusp of mitral valve Anterior cusp of mitral valve

Tendinous cords Papillary muscles

Papillary muscles Trabeculae carneae

Interventricular septum Left ventricle

A. Left Lateral View Apex of heart

Pulmonary trunk

Aorta

From left lung

From left lung

Superior vena cava Left superior pulmonary vein

From right lung

Right superior pulmonary vein

Left inferior pulmonary vein

Right inferior pulmonary vein

Inferior vena cava Lines of incision

Left atrium entered via pulmonary veins

Left atrioventricular orifice

Left ventricle

To aortic vestibule

Figure 3.56 A&C

B. Posterior View

3.56

C. Left Lateral View

LEFT ATRIUM AND LEFT VENTRICLE

A. Interior of left heart. B. Line of incision (black dashed line) for parts A and C. C. Blood ow through the left heart. • A diagonal cut was m ade from the base of the heart to the apex, passing between the superior and inferior pulm onary veins and through the posterior cusp of the m itral valve, followed by retraction (spreading) of the left heart wall on each side of the incision.

• The entrances (pulm onary veins) to the left atrium are posterior, and the exit (left atrioventricular or m itral ori ce) is anterior. • The left side of the fossa ovalis is also seen on the left side of the interatrial septum , although the left side is not usually as distinct as the right side is within the right atrium . • Except for that of the auricle, the atrial wall is sm ooth.

INTERNAL HEART AND VALVES

Th o rax

255

Aorta Pulmonary trunk

Posterior cusp of aortic valve Orifice of left coronary artery

Orifice of right coronary artery Fibrous ring

Right cusp of aortic valve

Left cusp of aortic valve

Interventricular septum, membranous part

Anterior cusp of mitral valve Tendinous cords

Interventricular septum, muscular part Anterior papillary muscle Posterior papillary muscle Left atrioventricular orifice Trabeculae carneae

Apex of heart

A. Left Anterior Oblique View of Open Left Ventricle

Ascending aorta

To systemic circulation

Pulmonary artery

Superior vena cava

Valve cusps Coronary sinus

Left cusp of aortic valve

Trabeculae carneae

Aortic vestibule Right atrium

Papillary muscle Left ventricle

From left atrium via left atrioventricular orifice

C B. Coronal CT

LEFT VENTRICLE A. Interior of left ventricle. B. Coronal CT image from coronary CT arteriography study. The patient was injected with an intravenous (IV) contrast agent and a series of CT images was taken as the contrast material traveled through the heart. For this image, the material has mainly passed through the right side of the heart and is primarily now in the left ventricle and aorta. C. Blood ow through the left ventricle. • A cut was m ade from the apex along the left m arg in of the heart, passing posterior to the pulm onary trunk, to op en the aortic vestibule and ascending aorta.

3.57 • The entrance (left atrioventricular, bicuspid, or m itral ori ce) is situated p osteriorly, and the exit (aortic ori ce) is superior. • The left ventricular wall is thin and m uscular near the apex, thick and m uscular superiorly, and thin and brous (nonelastic) at the aortic ori ce. • Two large papillary m uscles, the anterior from the anterior wall and the posterior from the posterior wall, control the adjacent halves of two cusps of the m itral valve with tendinous cords (chordae tendineae).

256

Th o rax

INTERNAL HEART AND VALVES

Oblique pericardial sinus Left atrium Arrow traversing transverse pericardial sinus Superior left pulmonary vein

Right pulmonary veins

Orifice of left coronary artery opening into coronary sinus Superior vena cava Left cusp of pulmonary valve (L)

Posterior cusp of aortic valve (P)

Left auricle

Left ventricle

Right atrium

Right auricle Anterior cusp of pulmonary valve (A) Orifice of right coronary artery opening into right coronary sinus Right cusp of pulmonary valve (R)

Right cusp of aortic valve (R)

A. Superior View

Left cusp of aortic valve (L)

Right ventricle

Truncus arteriosus Aortic valve

3.58

P P

VALVES OF HEART

A. Excised heart. • The ventricles are positioned anteriorly and to the left, the atria posteriorly and to the right. • The roots of the aorta and pulm onary artery, which conduct blood from the ventricles, are placed anterior to the atria. • The aorta and p ulm onary artery are enclosed within a com m on tube of serous pericardium and partly em braced by the auricles of the atria. • The transverse p ericardial sinus curves posterior to the enclosed stem s of the aorta and pulm onary trunk and anterior to the superior vena cava and upper lim its of the atria. B. Developm ental b asis for nam ing of p ulm onary and aortic valve cusps. The truncus arteriosus with four cusp s ( I) sp lits to form two valves, each with three cusps ( II) . The heart und ergoes partial rotation to the left on its axis, resulting in the arrangem ent of cusps shown in ( III) .

R

R

P

L

L

R

A Serous pericardium

A

Right coronary artery

II

Pulmonary valve

Semilunar Valves/Cusps

B

L R

L

I

Left coronary artery

R Right

A Anterior

L Left

P Posterior

L R

III

A

Th o rax

INTERNAL HEART AND VALVES

257

Left atrium Membranous septum, atrioventricular part

Septal cusp

Membranous septum, interventricular part (behind valve)

Posterior cusp

Anterior cusp Tendinous cords Anterior papillary muscle (sectioned)

Anterior papillary muscle (sectioned) Septal band of septomarginal trabecula

Left ventricle Posterior papillary muscle

Septal papillary muscle

A. Anterior View of Tricuspid Valve

Right atrium Anterior cusp Posterior cusp

*

Tendinous cords

*

Right ventricle Anterior papillary muscle (sectioned)

Anterior papillary muscle (sectioned)

Posterior papillary muscle

B. Anterior View of Mitral Valve

*Commissural cusps

Aortic sinus Orifice of right coronary artery

Right

Posterior

Left

Right coronary artery

Orifice of left coronary artery

Nodule Lunule

Left coronary artery Lunule

Nodule

P R

Left ventricle Right cusp (R)

Posterior cusp (P)

Left cusp (L)

C. Left Posterior Oblique View of Aortic Valve

VALVES OF THE HEART A. and B. Atrioventricular valves. C. and D. Sem ilunar valves. Tendinous cords pass from the tip s of the p apillary m uscles to the free m argins and ventricular surfaces of the cusps of the tricuspid ( A) and m itral ( B) valves. Each p ap illary m uscle or m uscle group controls the adjacent sides of two cusps, resisting valve prolapse during systole. In C the anulus of the aortic valve has been incised between the right and left cusps and spread open. Each cusp of the sem ilunar valves bears a nodule in the m idpoint of its

Right coronary artery

P L

Left coronary artery

R Right coronary artery

L Left coronary artery

D. Superior Views of Aortic Valve (Arrows indicate direction of blood flow)

3.59 free edge, anked by thin connective tissue areas (lunules). When the ventricles relax to ll (diastole), back ow of blood from aortic recoil or pulm onary resistance lls the sinus (space between cusp and d ilated part of the aortic or p ulm onary wall), causing the nodules and lunules to m eet centrally, closing the valve (D, left). Filling of the coronary arteries occurs during diastole (when ventricular walls are relaxed) as back ow “in ates” the cusps to close the valve.

258

Th o rax

SUPERIOR MEDIASTINUM AND GREAT VESSELS

Trachea

Esophagus

Right common carotid artery

Left subclavian artery

Right subclavian artery

Left common carotid artery

Brachiocephalic artery

Cervical pleura

Right brachiocephalic vein

Left brachiocephalic vein

Inferior thyroid veins

1st rib

Internal thoracic vein and artery

Thymus Internal thoracic artery

Thymic vein

Superior vena cava Fibrous pericardium (cut edge)

Ascending aorta

A. Anterior View

3.60

SUPERIOR MEDIASTINUM I AND II: SUPERFICIAL DISSECTIONS

A. Dissection I: Thym us in situ. The sternum and ribs have been excised and the pleurae rem oved. It is unusual in an adult to see such a discrete thym us, which is large during puberty but subsequently regresses and is for the m ost part replaced by fat and brous tissue. B. Dissection II: Thym us rem oved. C. Relationship of nerves and vessels. The right vagus nerve (CN X) crosses anterior to the right subclavian artery and gives off the right recurrent laryngeal nerve, which passes m edially to reach the trachea and esophagus. The left recurrent laryngeal nerve passes inferior and then posterior to the arch of the aorta and ascends between the trachea and esophagus to the larynx. The distal part of the ascending aorta receives a strong thrust of blood when the left ventricle contracts. Because its wall is not reinforced by brous pericardium (the brous pericardium blends with the aortic adventitia at the beginning of the arch), an aneurysm m ay develop. An ao rt ic an e urysm is evident on chest lm (radiograph of the thorax) or a m ag netic resonance angiogram as an enlarged area of the ascending aorta silhouette. Individuals with

an aneurysm usually com p lain of chest pain that radiates to the back. The aneurysm m ay exert pressure on the trachea, esophagus, and recurrent laryngeal nerve, causing dif culty in breathing and swallowing. Me d iast in al co m p re ssio n . The recurrent laryngeal nerves supply all the intrinsic m uscles of the larynx, except the cricothyroid. Conseq uently, any investigative p rocedure or disease process in the superior m ediastinum m ay involve these nerves and affect the voice. Because the left recurrent laryngeal nerve hooks around the arch of the aorta and ascends between the trachea and the esop hagus, it m ay be involved when there is a bronchial or esophageal carcinom a, enlargem ent of m ediastinal lym ph nodes, or an aneurysm of the arch of the aorta. The thym us is a prom inent feature during infancy and childhood. In som e infants, the thym us m ay com press the trachea. The thym us plays an im portant role in the developm ent and m aintenance of the im m une system . As puberty is reached, the thym us begins to dim inish in relative size. By adulthood, it is replaced by adipose tissue.

Th o rax

SUPERIOR MEDIASTINUM AND GREAT VESSELS

Right common carotid artery

Right vagus nerve Right subclavian artery

Recurrent laryngeal nerves

259

Esophagus Left vagus nerve Left subclavian artery Phrenic nerve

Trachea Phrenic nerve Internal thoracic artery

Left common carotid artery Cervical pleura

Brachiocephalic artery Left brachiocephalic vein

Right brachiocephalic vein

Left superior intercostal vein Left vagus nerve

1st rib Arch of aorta

Cardiac nerves Left recurrent laryngeal nerve Ligamentum arteriosum

Superior vena cava Pulmonary plexus Pericardium (cut edge) Phrenic nerve Ascending aorta

B. Anterior View

Right vagus nerve (CN X) Recurrent laryngeal nerve Anterior scalene muscle Right phrenic nerve Right subclavian artery Brachiocephalic trunk Right brachiocephalic vein Superior vena cava Left recurrent laryngeal nerve (posterior to aorta) Pulmonary trunk

C. Anterior View

SUPERIOR MEDIASTINUM I AND II (continued )

Left phrenic nerve Left common carotid artery Recurrent laryngeal nerve Left internal jugular vein Left brachiocephalic vein Left subclavian artery Left phrenic nerve Left vagus nerve (CN X) Arch of aorta Ligamentum arteriosum Thoracic (descending) aorta

3.60

Th o rax

260

SUPERIOR MEDIASTINUM AND GREAT VESSELS

Right recurrent laryngeal nerve Left recurrent laryngeal nerve

Right vagus nerve

Esophagus (E)

Right subclavian artery

Left subclavian artery

Cervical pleura

Left vagus nerve

Brachiocephalic trunk

Cervical cardiac nerves

Cervical cardiac nerves 1st rib Trachea (T) Arch of azygos vein

Arch of aorta

Cardiac plexus

Ligamentum arteriosum

Lymph nodes

Anterior pulmonary plexus

Right lung

Left pulmonary artery (LP)

Right pulmonary artery (RP)

Pulmonary trunk (PT)

Left lung Superior and inferior right pulmonary veins

Superior and inferior left pulmonary veins

Thoracic aorta (TA) Esophagus Left vagus nerve Anterior View

3.61

SUPERIOR MEDIASTINUM III: CARDIAC PLEXUS AND PULMONARY ARTERIES

T

E

E

E

T R B

TY

T LB

S V C AA

E

AR

AZ

T AR RP

AA

AZ

A

3.62

B

E AR

RBR T

LP

D

AR LBR

L

TA

C

L

E

TA

RELATIONS OF GREAT VESSELS AND TRACHEA

Ob serve, from sup er cial to d eep : (A) Thym us (TY); (B) The right (RB) and left (LB) brachiocephalic veins form the superior vena cava (SVC) and receive the arch of the azygos vein (AZ) posteriorly; (C) The ascending aorta (AA) and arch of the aorta (AR) arch over the

right pulm onary artery and left m ain bronchus; (D) The right and left pulm onary arteries (RP and LP); and (E) The tracheobronchial lym ph nodes (L) at the tracheal bifurcation (T). E, esophagus; LBR, left m ain bronchus; RBR, right m ain bronchus; TA, thoracic aorta.

Th o rax

SUPERIOR MEDIASTINUM AND GREAT VESSELS

Longus colli

261

Esophagus

Cervical pleura Thoracic duct Trachea

Left vagus nerve 1st rib

Left recurrent laryngeal nerve

Arch of aorta Arch of azygos vein

Ligamentum arteriosum

Left recurrent laryngeal nerve

Left bronchial artery

Left main bronchus

Right main bronchus Right bronchial artery

Intrapulmonary bronchi

Right lung

Esophagus Left lung

Thoracic (descending) aorta

A. Anterior View

Right vagus nerve Right recurrent laryngeal nerve Right 4th aortic arch Right 5th aortic arch (degenerated) Right 6th aortic arch (distal half degenerates) Foregut

B. Embryonic (6 Weeks)

Right vagus nerve

Left vagus nerve

Left vagus nerve Left recurrent laryngeal nerve

Right recurrent laryngeal nerve Left 4th aortic arch

Right subclavian artery (from right 4th aortic arch) Left recurrent laryngeal nerve Trachea Left 6th aortic arch

Arch of aorta (from left 4th aortic arch) Ligamentum arteriosum (from left 6th aortic arch) Left pulmonary artery

Esophagus Dorsal aorta

Anterior Views

C. Child

SUPERIOR MEDIASTINUM IV: TRACHEAL BIFURCATION AND BRONCHI A. Dissection. B. and C. Asymmetrical course of right and left recurrent laryngeal nerves. Arch VI disappears on the right, leaving the right recurrent laryngeal nerve to pass under arch IV, which becomes

Thoracic aorta

3.63

the right subclavian artery. Arch VI becomes part of the ductus arteriosus on the left side, and arch IV “descends” to become the arch of the aorta; thus, the left recurrent laryngeal nerve is pulled into the thorax.

Th o rax

262

SUPERIOR MEDIASTINUM AND GREAT VESSELS

Right common carotid artery (RC)

Left common carotid artery (LC)

Right subclavian artery (RS) R C

Thyrocervical trunk RS

Brachiocephalic trunk (BT)

L C

Left subclavian artery (LS)

Arch of aorta (AR)

LS

Internal thoracic artery BT Descending aorta (DA)

AR

Ascending aorta (AA) AA

A A. and B. Most common pattern (65%)

LC

RC RS

RS LS

BT

RC Left vertebral artery

RS

LC

BT

B. Aortic Angiogram, Left Anterior Oblique View LC

RC

RC

DA

LS

LS

LC

RS

LS BT

BT

BT

DA

AA

C

D

C. and D. Left common carotid artery originating from the brachiocephalic trunk (27%)

E

F

E. Four arteries originating independently

F. Right and left brachiocephalic

from the arch of the aorta (2.5%)

RC RS

trunks originating from the arch of the aorta (1.2%)

LC LS BT

AR

Coarctation

Ligamentum arteriosum

DA AA

G

3.64

BRANCHES OF AORTIC ARCH

A. and B. Most com m on pattern (65%). C–F. Variations. G. In co arct at io n o f t h e ao rt a, the arch or descending aorta has an abnorm al narrowing (stenosis) that dim inishes the caliber of the aortic lum en, producing an obstruction to blood ow. The m ost com m on

site is near the ligam entum arteriosum . When the coarctation is inferior to this site (p o st d uct al co arct at io n ), a good collateral circulation usually develops between the proxim al and distal parts of the aorta through the intercostal and internal thoracic arteries.

Th o rax

SUPERIOR MEDIASTINUM AND GREAT VESSELS

Right sympathetic trunk (cervical)

263

Cervicothoracic (stellate) ganglion (inferior cervical and 1st thoracic ganglia)

Right recurrent laryngeal nerve

Left vagus nerve Left recurrent laryngeal nerve Right vagus nerve

Arch of aorta

Esophageal branch

Aortic plexus (thoracic)

5th thoracic sympathetic ganglion

Esophagus

Greater splanchnic nerve Esophageal plexus Intercostal nerves Left sympathetic trunk (thoracic) Diaphragm

Anterior vagal trunk Posterior vagal trunk

Splanchnic nerves

Innervation

Celiac ganglion

Greater Lesser Least

Sympathetic Parasympathetic Plexuses (sympathetic and parasympathetic) Somatic

Celiac trunk Subcostal nerve Abdominal aorta

Right sympathetic trunk (lumbar) Right crus of diaphragm

A Trachea (T)

Esophagus (E)

Right recurrent laryngeal nerve Right vagus nerve Subclavian artery

Middle cervical ganglion

Left recurrent laryngeal nerve E T

Left vagus nerve

T1 sympathetic ganglion

Brachiocephalic trunk Cardiac plexus

Cervicothoracic ganglion

Arch of aorta Cardiac plexus

Right pulmonary plexus

Left pulmonary plexus

Left pulmonary plexus T3 sympathetic ganglion

Esophageal plexus

Descending aorta Esophageal plexus

B

CARDIAC AND PULMONARY PLEXUSES A. Overview. B. Parasym pathetic contribution. C. Sym pathetic contribution. He art . Sym pathetic stim ulation increases the heart’s rate and the force of its contractions. Parasym pathetic stim ulation slows the heart rate, reduces the force of contraction, and constricts the coronary arteries, saving energy between p eriods of increased dem and. While the cardiac plexus is shown in relation to the bifurcation of the trachea, note that it lies directly posterior to the

C

3.65 superior m argin of the heart (see Fig. 3.28C) and in close proxim ity to the nodal tissue and origins of the coronary arteries. Lun g s. Sym pathetic bers are inhibitory to the bronchial m uscle (bronchodilator), m otor to pulm onary vessels (vasoconstrictor), and inhibitory to the alveolar glands of the bronchial tree. Parasym p athetic b ers from CN X are bronchoconstrictors, secretory to the glands of the bronchial tree (secretom otor).

Th o rax

264

SUPERIOR MEDIASTINUM AND GREAT VESSELS

Internal thoracic vein and artery Right brachiocephalic vein

Sternum

Phrenic nerve

Sternal reflection of (parietal) pleurae

1st intercostal nerve Anterior scalene

Superior vena cava

Ansa subclavia t 1s

Subclavian artery

rib

Arch of aorta (interior)

Right recurrent laryngeal nerve Scalenus minimus Anterior ramus C8

Right vagus nerve

Inferior trunk of brachial plexus

Trachea

Middle scalene Cervicothoracic (stellate) ganglion

d 2n

Esophagus

rib

Superior intercostal vein

Anterior ramus T1 Branch of supreme intercostal artery

d 3r

rib

Sympathetic trunk Body of vertebra

Internal intercostal Intercostal nerve and posterior intercostal vessels

Parietal pleura (purple)

Endothoracic fascia (gray)

Inferior View

ri b

ri b

ri b

1s t

• The cervical, costal, and m ediastinal parietal pleura (purple) and portions of the endothoracic fascia (gray) have been rem oved from the right side of the sp ecim en to dem onstrate structures traversing the sup erior thoracic ap erture. • The rst part of the subclavian artery disappears as it crosses the 1st rib anterior to the anterior scalene m uscle. • The ansa subclavia from the sym pathetic trunk and right recurrent laryngeal nerve from the vagus are seen looping inferior to the subclavian artery. • The anterior ram i of C8 and T1 m erge to form the inferior trunk of the brachial plexus, which crosses the 1st rib posterior to the anterior scalene m uscle.

Sternum

2n d

SUPERIOR MEDIASTINUM AND ROOF OF PLEURAL CAVITY

3r d

3.66

Thoracic outlet

DIAPHRAGM Left sternal reflection of parietal pleura Costomediastinal recess

Sternum

Th o rax

265

Right sternal reflection of parietal pleura Internal thoracic artery

Fat pad Transversus thoracis

Left phrenic nerve

External oblique Pericardial sac

Muscular part of diaphragm

Right phrenic nerve Inferior vena cava

Esophagus Central tendon of diaphragm

Central tendon of diaphragm Diaphragmatic pleura

Meso-esophagus Latissimus dorsi

Costodiaphragmatic recess

Serratus posterior inferior

Costal pleura Aorta

A. Superior View

Thoracic duct

Azygos vein

Greater (thoracic) splanchnic nerve

Sympathetic trunk

DIAPHRAGM AND PERICARDIAL SAC

Pericardium Esophagus Meso-esophagus Aorta

Mediastinal pleura

B. Superior View

3.67

A. The diaphragm atic pleura is m ostly rem oved. The pericardial sac is situated on the anterior half of the diaphragm ; one third is to the right of the m edian plane, and two thirds to the left. Note also that anterior to the pericardium , the sternal re ection of the left pleural sac approaches but fails to m eet that of the right sac in the m edian plane; and on reaching the vertebral colum n, the costal pleura becom es the m ediastinal pleura. Irrit at io n o f t h e p arie t al p le ura produces local pain and referred pain to the areas sharing innervation by the sam e segm ents of the spinal cord. Irrit at io n o f t h e co st al an d p e rip h e ral p art s o f t h e d iap h rag m at ic p le ura results in local p ain and referred pain along the intercostal nerves to the thoracic and abd om inal walls. Irrit at io n o f t h e m e d iast in al an d ce n t ral d iap h rag m at ic p art s o f t h e p arie t al p le ura results in p ain that is referred to the root of the neck and over the shoulder (C3–C5 derm atom es). B. Between the inferior part of the esophagus and the aorta, the right and left layers of m ediastinal pleura form a dorsal m eso-esophagus, especially when the body is in the p rone p osition.

266

Th o rax

POSTERIOR THORAX

Trachea

Esophagus Vertebral artery

Right common carotid artery

Costocervical trunk Thyrocervical trunk

Right subclavian artery

Internal thoracic artery

Brachiocephalic trunk

Left subclavian artery Left common carotid artery Arch of aorta

Arch of azygos vein Tracheobronchial lymph node Right main bronchus

Left main bronchus Left superior lobar bronchus

Right superior lobar bronchus Intermediate bronchus (to right inferior and middle lobes) Esophagus

Left inferior lobar bronchus Thoracic aorta

Thoracic duct

Esophageal hiatus Diaphragm

Abdominal aorta

Anterior View

Cisterna chyli Right crus of diaphragm

3.68

Median arcuate ligament

Left crus of diaphragm

ESOPHAGUS, TRACHEA, AND AORTA

• The anterior relations of the thoracic part of the esophagus from superior to inferior are the trachea (from origin at cricoid cartilage to bifurcation), right and left bronchi, inferior tracheobronchial lymph nodes, pericardium (not shown) and, nally, the diaphragm. • The arch of the aorta p asses p osterior to the left of these four structures as it arches over the left m ain bronchus; the arch of the azygos vein passes anterior to their right as it arches over the right m ain bronchus.

• Eso p h a g e a l im p re ssio n s. The im p ressions p rod uced in the esop h ag us b y ad jacen t structures (aorta, left m ain b ron ch us, an d esop h ag eal h iatus) are of clin ical in terest b ecause of th e slower p assag e of sub stan ces at th ese sites. Th e im p ressions in d icate where swallowed foreig n b od ies are m ost likely to lod g e and wh ere a stricture m ay d evelop after th e accid en tal d rinking of a caustic liq uid such as lye.

POSTERIOR THORAX

Th o rax

267

Thyroid gland Inferior thyroid artery Trachea

Thoracic duct Trachea

Arch of aorta Right bronchial artery Left bronchial arteries Azygos vein Thoracic aorta Thoracic aorta

Esophagus

Esophagus

Posterior intercostal artery

Esophageal branches of thoracic aorta

Esophageal branches of thoracic aorta

Esophageal branch of left inferior phrenic artery Esophageal branch of left inferior phrenic artery

Esophageal branch of left gastric artery

Esophageal branches of left gastric artery

B. Left Anterolateral View

A. Right Anterolateral View Deep cervical artery

Posterior intercostal arteries: 1st

Costocervical trunk 1st rib

2nd 3rd

Ligamentum arteriosum

4th 5th 6th 7th

*

*

Bronchial arteries

*Coronary arteries Esophageal branches

8th 9th

Posterior intercostal arteries

10th 11th Subcostal artery

C. Anterior View

Superior phrenic arteries Subcostal artery Diaphragm Celiac trunk

ARTERIAL SUPPLY TO TRACHEA AND ESOPHAGUS

3.69

A. and B. Arteries of trachea and esophagus. The continuous anastom otic chain of arteries on the esop hagus is form ed (1) by branches of the right and left inferior thyroid and right suprem e intercostal arteries superiorly, (2) by the unpaired m edian aortic (bronchial and esophageal) branches, and (3) b y branches of the left gastric and left inferior phrenic arteries inferiorly. The right bronchial artery usually arises from the superior left bronchial or 3rd right p osterior intercostal artery (here the 5th) or from the aorta directly. The unpaired m edian aortic branches also sup ply the trachea and bronchi. C. Branches of the thoracic aorta.

Th o rax

268

POSTERIOR THORAX

Left internal jugular vein

Right internal jugular vein

Jugular lymphatic trunk

Jugular lymphatic trunk

Thoracic duct

Right lymphatic duct

Subclavian lymphatic trunk Subclavian lymphatic trunk Right venous angle

Left venous angle

Right subclavian vein

Left subclavian vein

Right bronchomediastinal lymphatic trunk Left brachiocephalic vein

Right brachiocephalic vein

Left bronchomediastinal lymphatic trunk

Superior vena cava

Left superior intercostal vein

Azygos vein Intercostal lymphatic vessel

Thoracic duct Thoracic aorta Posterior mediastinal lymph node

Intercostal lymphatic vessel

Diaphragm

Inferior vena cava

Esophagus

Anterior View Cisterna chyli (chyle cistern)

3.70

THORACIC DUCT

• The descending aorta is located to the left, and the azygos vein slightly to the right of the m idline. • The thoracic duct (1) originates from the cisterna chyli at the T12 vertebral level, (2) ascends on the vertebral colum n between the azygos vein and the descending aorta, (3) passes to the left at the junction of the posterior and superior m ediastina, and continues its ascent to the neck, where (4) it arches laterally to enter the venous system near or at the angle of union of the left internal jugular and subclavian veins (left venous angle). • The thoracic duct is com m only p lexiform (resem bling a network) in the posterior m ediastinum .

• The term ination of the thoracic duct typically receives the left jugular, subclavian, and bronchom ediastinal trunks. • The right lym ph duct is short and form ed by the union of the right jugular, subclavian, and bronchom ediastinal trunks. • Because the thoracic duct is thin-walled and m ay be colorless, it m ay not b e easily identi ed. Conseq uently, it is vulnerable to inadvertent injury during investigative and/ or surgical procedures in the posterior m ediastinum . Lace rat io n o f t h e t h o racic d uct results in chyle escaping into the thoracic cavity. Chyle m ay also enter the p leural cavity, p roducing chylothorax.

POSTERIOR THORAX Area draining to right lymphatic duct (gray)

Th o rax

269

Blood flow

Area draining to thoracic duct (pink)

Arteriole

Blood flow

Left internal jugular vein

Venule

Lymphatic capillaries

Superficial cervical nodes Deep cervical nodes

Tissue cells

Thoracic duct

Right lymphatic duct

Left subclavian vein

Right subclavian vein

Anterior axillary nodes Posterior mediastinal nodes Central and posterior axillary nodes

Thoracic duct Superficial lymphatic vessels

Deep lymphatic vessels

Interstitial fluid Capillary bed

Cisterna chyli

Cubital nodes

Cubital (supratrochlear) nodes

Afferent lymphatic vessel to node

Lymph flow

Lumbar (caval/aortic) nodes Iliac nodes

Lymphatic valve

Lymphatic valve

Artery To thoracic duct Deep inguinal nodes

Superficial inguinal nodes

Vein

Efferent lymphatic vessel to vein or to secondary node

Lymph node

B. Schematic Illustration Deep popliteal nodes

Superficial popliteal nodes

Deep lymphatic vessels

Superficial lymphatic vessels

Vessels Veins Superficial Deep Lymphatic vessels and nodes Superficial Deep

LYMPHATIC SYSTEM A. Anterior View

3.71

A. Overview of super cial and deep lym phatics. B. Lym phatic capillaries, vessels, and nodes. Arrows (black) indicate the ow (leaking of interstitial uid out of blood vessels and absorp tion) into the lym phatic capillaries.

270

Th o rax

POSTERIOR THORAX

Left brachiocephalic vein Right brachiocephalic vein Left superior intercostal vein Arch of aorta

Superior vena cava

Azygos vein

Left posterior intercostal veins

Accessory hemi-azygos vein

Parietal pleura (cut edge)

Right posterior intercostal veins

Hemi-azygos vein

Parietal pleura (cut edge) Vertebral body T11

Diaphragm

Costodiaphragmatic recess

Celiac artery Superior mesenteric artery

Left renal vein Inferior vena cava

Aorta

A. Anterior View

3.72

AZYGOS SYSTEM OF VEINS

A. Dissection. B. Schem atic illustration. The ascending lum bar veins connect the com m on iliac veins to the lum b ar veins and join the subcostal veins to becom e the lateral roots of the azygos and hem i-azygos veins; the m edial roots of the azygos and hem iazygos veins are usually from the inferior vena cava and left renal vein, if p resent. Typically, the up per four left posterior intercostal veins drain into the left brachiocephalic vein, d irectly and via the left superior intercostal veins.

The hem i-azygos, accessory hem i-azygos, and left superior intercostals veins are continuous in A, but m ost com m only, they are discontinuous as in B. The hem i-azygos vein crosses the verteb ral colum n at app roxim ately T9, and the accessory hem i-azygos vein crosses at T8, to enter the azygos vein ( B) . In contrast, there are four cross-connecting channels between the azygos and hem iazygos system s in A. The azygos vein arches sup erior to the root of the right lung at T4 to drain into the superior vena cava.

POSTERIOR THORAX

Th o rax

271

Thoracic duct Posterior intercostal veins: 1

1 2

2 Superior vena cava

3

3

4

4

5

5

Azygos vein 6

Subcostal vein

6

7

7

8

8

9

9

Oblique vein of left atrium draining into coronary sinus

Accessory hemi-azygos vein

Hemi-azygos vein

10

10

11

11

12

Left superior intercostal vein

12

Lumbar veins: 1 1

2

Left renal vein

2

Inferior vena cava 3

3 Ascending lumbar vein

4

4

5 Right common iliac vein

Iliolumbar vein

Left common iliac vein

B. Anterior View

AZYGOS SYSTEM OF VEINS (continued ) The azygos, hemi-azygos, and accessory hemi-azygos veins offer alternate means of venous drainage from the thoracic, abdominal, and back regions when ob struction of th e IVC occurs. In some people, an accessory azygos vein parallels the main azygos vein on the right side. Other people have no hemi-azygos system of veins. A clinically important variation, although uncommon, is when the azygos system

3.72 receives all the blood from the IVC, except that from the liver. In these people, the azygos system drains nearly all the blood inferior to the diaphragm, except that from the digestive tract. When ob struction of the SVC occurs superior to the entrance of the azygos vein, blood can drain inferiorly into the veins of the abdominal wall and return to the right atrium through the IVC and azygos system of veins.

272

Th o rax

POSTERIOR THORAX

Longus colli

Subclavian artery

Esophagus

Anterior scalene Clavicle Subclavian vein Brachiocephalic trunk Internal thoracic artery

Ramus communicans

Right brachiocephalic vein Right vagus nerve on trachea

Sympathetic ganglion

Left brachiocephalic vein

Sympathetic trunk (interganglionic branch)

Internal thoracic vein Phrenic nerve Superior vena cava

Arch of azygos vein

Pericardiacophrenic artery Mediastinal part of parietal pleura (cut edge) Pericardial sac Posterior vein intercostal artery

Bronchus Inferior pulmonary vein

Intercostal nerve

Costal part of parietal pleura (cut edge)

Diaphragm

Right Lateral View

3.73

Greater splanchnic nerve

Azygos vein

Esophageal plexus

Inferior vena cava

Fat pad

MEDIASTINUM, RIGHT SIDE

• The costal and m ediastinal p leurae have m ostly been rem oved, exp osing the underlying structures. Com p are with the m ediastinal surface of the right lung in Figure 3.32. • The right side of the m ediastinum is the “b lue side,” dom inated by the arch of the azygos vein and the superior vena cava. • Both the trachea and the esophagus are visible from the right side.

• The right vagus nerve descends on the m edial surface of the trachea, passes m edial to the arch of the azygos vein, posterior to the root of the lung, and then enters the esophageal plexus. • The right phrenic nerve passes anterior to the root of the lung lateral to both venae cavae.

Th o rax

POSTERIOR THORAX

273

Supreme intercostal artery Ganglion Sympathetic Trunk

Left subclavian artery

Thoracic duct

Left subclavian vein

Vein Artery Posterior intercostal Intercostal nerve

Left common carotid artery

Esophagus

Internal thoracic artery and vein

Left superior intercostal vein Arch of aorta Left vagus nerve

Left brachiocephalic vein

Left recurrent laryngeal nerve Ligamentum arteriosum Accessory hemi-azygos vein

Pericardial sac Mediastinal part of parietal pleura (cut edge)

Pulmonary artery Bronchi

Costal part of parietal pleura (cut edge)

Root of lung

Pulmonary veins

Left phrenic nerve Hemi-azygos vein

Rami communicantes

Sympathetic trunk Diaphragm

Left Lateral View Fat pad

Esophagus Descending (thoracic) aorta

MEDIASTINUM, LEFT SIDE • Com p are with th e m ed iastin al surface of th e left lun g in Fig ure 3.33. • The left side of the m ediastinum is the “red side,” dom inated by the arch and descending portion of the aorta, the left com m on carotid and subclavian arteries; the latter obscure the trachea from view.

Greater splanchnic nerve

3.74 • The thoracic duct can be seen on the left side of the esophagus. • The left vagus nerve passes posterior to the root of the lung, sending its recurrent laryngeal branch around the lig am entum arteriosum inferior and then m edial to the aortic arch. • The phrenic nerve passes anterior to the root of the lung and penetrates the diaphragm m ore anteriorly than on the right side.

Th o rax

274

POSTERIOR THORAX

Brachial plexus Anterior scalene

Left common carotid artery Left subclavian artery Brachiocephalic trunk

Sympathetic ganglion

Rami communicantes

Posterior Vein intercostal Artery Intercostal nerve

Azygos vein

Trachea

Esophagus (cut end)

Thoracic duct Descending thoracic aorta

Sympathetic trunk (thoracic) Greater splanchnic nerve

Lesser splanchnic nerve Inferior vena cava

Right crus of diaphragm

Esophagus (cut end)

Diaphragm Celiac artery Superior mesenteric artery Stomach

Right Anterior Oblique View

3.75

STRUCTURES OF POSTERIOR MEDIASTINUM I

• In this specim en, the parietal pleura is intact on the left side and partially rem oved on the right side. A portion of the esophagus, between the bifurcation of the trachea and the diaphragm , is also rem oved. • The thoracic sym p athetic trunk is connected to each intercostal nerve by ram i com m unicantes.

• The greater splanchnic nerve is form ed by bers from the 5th to 10th thoracic sym pathetic ganglia, and the lesser splanchnic nerve receives bers from the 10th and 11th thoracic ganglia. Both nerves contain presynaptic and visceral afferent b ers. • The azygos vein ascends anterior to the intercostal vessels and to the right of the thoracic duct and aorta and drains into the superior vena cava.

POSTERIOR THORAX

Th o rax

275

Superior lobe of right lung Thoracic duct

Esophagus

Sympathetic trunk

Aorta External Intercostal Innermost muscles Internal

Azygos vein

Inferior lobe of right lung Posterior Vein Intercostal Artery

Parietal pleura (cut edge) Rami communicantes

Intercostal nerve Thoracic duct Hemi-azygos vein Azygos vein Greater splanchnic nerve

Cisterna chyli

Spinal cord Diaphragm Dural sac Posterior ramus of spinal nerve

Posterior View

STRUCTURES OF POSTERIOR MEDIASTINUM II • The thoracic verteb ral colum n and thoracic cage are rem oved on the right. On the left, the ribs and intercostal m usculature are rem oved posteriorly as far laterally as the angles of the ribs. The parietal pleura is intact on the left side but partially rem oved on the right to reveal the visceral pleura covering the right lung.

3.76 • The azygos vein is on the right side, and the hem i-azygos vein is on the left, crossing the m idline (usually at T9 but higher in this sp ecim en) to join the azygos vein. The accessory hem i-azygos vein is absent in this specim en; instead, three m ost superior posterior intercostal veins drain directly into the azygos vein.

276

Th o rax

OVERVIEW OF AUTONOMIC INNERVATION

Trachea

Esophagus Left vagus nerve

Right vagus nerve Right recurrent laryngeal nerve

Superior cervical cardiac branch

Right subclavian artery

Cervicothoracic (stellate) ganglion (inferior cervical and 1st thoracic ganglia) Left recurrent laryngeal nerve

Recurrent cardiac branch Inferior cervical cardiac nerve

B

Inferior cervical cardiac nerve Inferior cervical cardiac branch Thoracic cardiac branches

Arch of aorta

Right sympathetic trunk Cardiac plexus Right pulmonary plexus

Aortic plexus (thoracic) Left pulmonary plexus

Pulmonary trunk

Right atrium

Right ventricle

C

Cardiac plexus

Left ventricle

A. Anterior View

D

3.77

OVERVIEW OF AUTONOMIC AND VISCERAL AFFERENT INNERVATION OF THE THORAX

A. Innervation of heart. B–D. Areas of cardiac referred pain (red). E. Innervation of posterior and superior m ediastina. The heart is insensitive to touch, cutting, cold, and heat; however, ischem ia and the accum ulation of m etabolic products stim ulate pain endings in the m yocardium . The afferent pain bers run centrally in the m iddle and inferior cervical branches and especially in the thoracic cardiac branches of the sym pathetic trunk. The axons of these prim ary sensory neurons enter spinal cord segm ents T1 through T4 or T5, especially on the left side. Card iac re fe rre d p ain is a phenom enon whereby noxious stim uli originating in the heart are perceived by a person as pain arising from a super cial p art of the body—the skin on the left upper lim b, for exam ple. Visceral referred pain is transm itted by visceral afferent bers accom panying sym pathetic bers and is typ ically referred to som atic structures or areas such as a lim b having afferent bers with cell bodies in the sam e sp inal ganglion, and central

processes that enter the sp inal cord through the sam e p osterior roots (Hardy & Naftel, 2001). An g in al p ain is com monly felt as radiating from the substernal and left pectoral regions to the left shoulder and the medial aspect of the left upper limb (B). This part of the limb is supplied by the m edial cutaneous nerve of the arm . Often, the lateral cutaneous branches of the 2nd and 3rd intercostal nerves (the intercostobrachial nerves) join or overlap in their distribution with the medial cutaneous nerve of the arm. Consequently, cardiac pain is referred to the upper limb because the spinal cord segm ents of these cutaneous nerves (T1–T3) are also common to the visceral afferent term inations for the coronary arteries. Synaptic contacts may also be made with commissural (connector) neurons, which conduct impulses to neurons on the right side of com parable areas of the spinal cord. This occurrence explains why pain of cardiac origin, although usually referred to the left side, may be referred to the right side, both sides, or the back (C and D).

Th o rax

OVERVIEW OF AUTONOMIC INNERVATION

277

Right sympathetic trunk (cervical) Cervicothoracic (stellate) ganglion (inferior cervical and 1st thoracic ganglia)

Right recurrent laryngeal nerve

Left vagus nerve Right vagus nerve Left recurrent laryngeal nerve Cardiopulmonary splanchnic nerves

Arch of aorta

Aortic plexus (thoracic)

Esophageal branch

5th thoracic sympathetic ganglion

Esophagus

Greater splanchnic nerve

Esophageal plexus Intercostal nerves

Left sympathetic trunk (thoracic) Diaphragm

Anterior vagal trunk Posterior vagal trunk Celiac ganglion Greater Splanchnic nerves

Celiac trunk

Lesser Least

Subcostal nerve

Right sympathetic trunk (lumbar)

Abdominal aorta

Right crus of diaphragm Key Sympathetic

E. Anterior View

Parasympathetic Mixed sympathetic and parasympathetic Somatic

OVERVIEW OF AUTONOMIC AND VISCERAL AFFERENT INNERVATION OF THORAX (continued )

3.77

Th o rax

278

OVERVIEW OF LYMPHATIC DRAINAGE OF THORAX

Areas of thorax (superficial and deep):

Thymus

Right internal jugular vein

Left internal jugular vein

Right jugular trunk

Drained by right lymphatic duct

Thoracic duct

Right subclavian trunk

Drained by thoracic duct

Left subclavian vein

Right subclavian vein Right lymphatic duct

Left bronchomediastinal trunk

Right bronchomediastinal trunk Sternum To parasternal nodes

Parasternal nodes

4th costal cartilage Diaphragm

Axillary nodes

To superior diaphragmatic nodes

To axillary nodes

A

Xiphoid process

Transumbilical plane

Right bronchomediastinal trunk Right internal jugular vein

B

Superior diaphragmatic (phrenic) nodes

Trachea

Trachea Arch of aorta

Right lymphatic duct

Thoracic duct

Right subclavian vein Right brachiocephalic vein

Brachiocephalic node

Inferior tracheobronchial (carinal) node

Brachiocephalic node

Anterior mediastinal node

Bronchopulmonary nodes Left auricle

Right main bronchus

Left internal jugular vein

Left coronary trunk

Left subclavian vein Left brachiocephalic vein Arch of aorta Left main bronchus

Bronchopulmonary node

Pulmonary trunk

Pulmonary trunk Right atrium

Left ventricle

Left ventricle

Right atrium

Right coronary trunk

Right ventricle

Right ventricle Inferior vena cava

C Anterior Views

3.78

Area drained by left coronary trunk

D

Superior diaphragmatic (phrenic) node

Area drained by right coronary trunk

OVERVIEW OF LYMPHATIC DRAINAGE OF THORAX

A. Super cial lym phatic drainage. B. Deep lym phatic drainage of parasternal nodes. C. Lym p hatic drainage of left side of heart. D. Lym phatic drainage of right side of heart.

OVERVIEW OF LYMPHATIC DRAINAGE OF THORAX

Left internal jugular vein Deep cervical node Right jugular trunk

Esophagus

Trachea

Right subclavian trunk

Paraesophageal node Right internal jugular vein Left jugular trunk Deep cervical node Thoracic duct

Right lymphatic duct

279

Lymphatic drainage of esophagus to

Left bronchomediastinal trunk

Right subclavian vein

Th o rax

Jugular trunks Bronchomediastinal trunks Superior diaphragmatic nodes Celiac (abdominal) nodes

Left subclavian vein

Right bronchomediastinal trunk Paratracheal nodes

Node of ligamentum arteriosum Superior tracheobronchial node Inferior tracheobronchial (carinal) node

Intrapulmonary nodes

Bronchopulmonary (hilar) nodes

Bronchopulmonary (hilar) node

Intrapulmonary node

Azygos vein

Paraesophageal node

Pulmonary ligament

Descending aorta

Inferior vena cava

To superior diaphragmatic (phrenic) nodes

Right phrenic nerve

Left phrenic nerve Superior diaphragmatic (phrenic) node

Superior diaphragmatic (phrenic) nodes

E. Anterior View

Fibrous pericardium (cut edge)

Left internal jugular vein Right bronchomediastinal trunk

F

Trachea Right internal jugular vein

Left bronchomediastinal trunk

Right lymphatic duct

Right bronchomediastinal trunk Left subclavian vein Left Superior vena cava bronchomediastinal trunk Azygos vein Superior vena cava Bronchopulmonary Prevertebral nodes nodes

Right subclavian vein Paratracheal node Arch of aorta

Inferior tracheobronchial (carinal) nodes

Bronchopulmonary node

Thoracic duct

Intercostal nodes Posterior intercostal vein Prevertebral nodes

Intercostal node

Left pulmonary veins

Left atrium

Hemi-azygos vein

Diaphragm

Right atrium Left coronary trunk

Superior diaphragmatic (phrenic) node Inferior vena cava

Left ventricle

G. Postero-inferior View

Right ventricle

Superior diaphragmatic (phrenic) node

Subcostal vein

Right coronary trunk Cisterna chyli

Area drained by left coronary trunk Area drained by right coronary trunk

H. Anterior View

OVERVIEW OF LYMPHATIC DRAINAGE OF THORAX (continued ) E. Lym phatic drainage of lungs, esophagus, and superior surface of diaphragm . F. Lym phatic drainage of esophagus. G. Lym phatic

Superior diaphragmatic (phrenic) node

Lymphatic drainage from abdomen and lower limbs

3.78

drainage of posterior and inferior surfaces of heart. H. Lym phatic drainage of posterior m ediastinum .

280

Th o rax

SECTIONAL ANATOMY AND IMAGING

A

B C D E

Pectoralis major Manubrium

Sternoclavicular joint Thymus

Left brachiocephalic vein Right brachiocephalic vein

Left common carotid artery

Brachiocephalic trunk

Esophagus

Trachea

LL T4

Right lung

Left subclavian artery Left lung Spinal cord Deep back muscles

A

Pulmonary trunk

Ascending aorta Superior vena cava Right pulmonary artery

Left pulmonary artery LL

RL

Left main bronchus Esophagus Descending aorta

Azygos vein T7 Right lung

Spinal cord Deep back muscles

B

3.79

TRANSVERSE (AXIAL) MRIs OF THORAX (A–E)

SECTIONAL ANATOMY AND IMAGING

Th o rax

281

Sternum Pulmonary trunk

Right atrium

Ascending aorta Superior vena cava

Anterior interventricular artery

Right pulmonary vein

Left coronary artery Left atrium

Esophagus Descending aorta

Azygos vein

T8

Right lung

Left lung Spinal cord

Deep back muscles

C Sternum

Internal thoracic artery

Pulmonary infundibulum Cusp of aortic valve

Right atrium

Left atrium Esophagus

Right pulmonary vein

Descending aorta T9

Right lung

Left lung

Spinal cord Deep back muscles

D Sternum Right ventricle

Pericardium

Anterior interventricular artery Right atrium

Papillary muscle Left ventricle

Right lung Left atrium

Esophagus

Descending aorta

Azygos vein T10

Hemi-azygos vein Left lung

Head of rib

Spinal cord

E

TRANSVERSE (AXIAL) MRIs OF THORAX (continued )

Deep back muscles

3.79

Th o rax

282

SECTIONAL ANATOMY AND IMAGING

Arch of aorta Right lung

Pulmonary trunk

Ascending aorta

Left auricle Left lung

Right atrium Left ventricle Right dome of diaphragm Left dome of diaphragm

Costodiaphragmatic recess

Costodiaphragmatic recess

A. Coronal MRI through Ascending and Arch of Aorta

Right common carotid artery

Trachea

Right brachiocephalic vein Brachiocephalic trunk

Left common carotid artery Arch of aorta

Right lung

Left pulmonary artery Pulmonary trunk

Superior vena cava

Left atrium Left lung

Left ventricle

Right dome of diaphragm Right atrium

Left dome of diaphragm

Inferior vena cava

B. Coronal MRI through Superior and Inferior Vena Cava

3.80

CORONAL MRIs OF THORAX

Th o rax

SECTIONAL ANATOMY AND IMAGING

283

Right lung

Right lung

Right main bronchus

Superior vena cava

Right pulmonary artery Left atrium

Right atrium Pericardium

Fat

Inferior vena cava

A. Sagittal MRI through Superior and Inferior Vena Cava

Left lung

Left common carotid artery

Left subclavian artery

Left brachiocephalic vein

Arch of aorta Right pulmonary artery Left main bronchus

Left lung Ascending aorta

Left atrium

Right ventricle Descending aorta

Left ventricle

B. Sagittal MRI through Arch of Aorta

SAGITTAL MRIs OF THORAX

3.81

Th o rax

284

SECTIONAL ANATOMY AND IMAGING

A B C D E

Superior right pulmonary vein (SRPV) Superior vena cava (SVC) SRPV

Ascending aorta (AA)

PT

AA

Pulmonary trunk (PT)

SVC

Right pulmonary artery (RPA) RPA

SLPV

LPA

Superior left pulmonary vein (SLPV) Right primary bronchus Left pulmonary artery (LPA) Left primary bronchus

A

ST

Sternum (ST) Left coronary artery (LCA)

Right atrium (RA)

RV

RA

Right ventricle (RV) AA

Ascending aorta (AA)

LCA

Superior left pulmonary vein (SLPV)

SRPV SLPV

LA

LPA

V

DA

Superior right pulmonary vein (SRPV) Left atrium (LA)

Descending aorta (DA) Vertebra (V)

B

3.82

TRANSVERSE OR HORIZONTAL (AXIAL) 3D VOLUME RECONSTRUCTIONS (LEFT SIDE OF PAGE) AND CT ANGIOGRAMS OF THORAX (A–E)

SECTIONAL ANATOMY AND IMAGING

Th o rax

285

Sternum (ST)

ST

Left coronary artery (LCA) Left pulmonary artery (LPV) RCA

Right ventricle (RV) RV

RA AA

Right coronary artery (RCA) Right atrium (RA)

LCA

Left ventricle (LV) Ascending aorta (AA)

SRPV

Superior right pulmonary vein (SRPV) LA

SLPV LPA ILPV DA

Left atrium (LA) Inferior left pulmonary vein (ILPV) Descending aorta (DA)

V

C

Superior left pulmonary vein (SLPV)

Vertebra (V)

Sternum (ST)

ST

Right ventricle (RV) RV

Right atrium (RA) Left ventricle (LV)

RA LV

Mitral valve (MV)

MV LA

Left atrium (LA)

IRPV

Inferior right pulmonary vein (IRPV) ILPV DA

Descending aorta (DA)

V

D

Vertebra (V)

ST

Right ventricle (RV)

RV

RCA

Right coronary artery (RCA) LV

RA

Left ventricle (LV) Right atrium (RA) Left atrium (LA)

LA DA V

E

LPV Descending aorta (DA) Vertebra (V)

TRANSVERSE OR HORIZONTAL (AXIAL) 3D VOLUME RECONSTRUCTIONS (LEFT SIDE OF PAGE) AND CT ANGIOGRAMS OF THORAX (A–E) (continued )

3.82

CHAPTER 4

Ab d o m e n Overview ...........................................................................288 Anterolateral Abdom inal Wall.............................................290 Inguinal Region .................................................................300 Testis .................................................................................310 Peritoneum and Peritoneal Cavity ......................................312 Digestive System ...............................................................322 Stom ach ............................................................................323 Pancreas, Duodenum , and Spleen .....................................326 Intestines ...........................................................................330 Liver and Gallbladder .........................................................340 Biliary Ducts.......................................................................350 Portal Venous System .........................................................354 Posterior Abdom inal Viscera ...............................................356 Kidneys ..............................................................................359 Posterolateral Abdom inal Wall ...........................................363 Diaphragm ........................................................................368 Abdom inal Aorta and Inferior Vena Cava............................369 Autonom ic Innervation ......................................................370 Lym phatic Drainage ...........................................................376 Sectional Anatom y and Im aging ........................................380

288

Ab d o m e n

OVERVIEW

Right lung

Left lung

Outline of diaphragm

Outline of esophagus

Outline of parietal pleura

Apex of heart Liver Pylorus of stomach

Spleen Outline of pancreas

Fundus of gallbladder

Outline of duodenum Ascending colon

Stomach

Transverse colon Jejunum Small intestine Ileum

Cecum Anterior superior iliac spine

Descending colon

Urinary bladder

A. Anterior View

4.1

ABDOMINAL VISCERA IN SITU

OVERVIEW

Ab d o m e n

Left lung

289

Right lung

Scapula

Outline of esophagus Outline of diaphragm Left suprarenal gland

Outline of parietal pleura

Outline of stomach Liver Spleen

Right suprarenal gland

Left kidney Right kidney Outline of pancreas

Descending colon

Outline of duodenum Ascending colon Right ureter

Small intestine Cecum Appendix Sigmoid colon Rectum Urinary bladder

B. Posterior View

ABDOMINAL VISCERA IN SITU (continued )

4.1

290

Ab d o m e n

ANTEROLATERAL ABDOMINAL WALL

Location of xiphoid process

Tendinous intersections of rectus abdominis

Serratus anterior

External oblique

Linea semilunaris

Location of linea alba

Umbilicus Rectus abdominis

Location of anterior superior iliac spine (ASIS)

Location of linea alba

Inguinal groove (location of inguinal ligament)

Location of pubic symphysis

Anterior View

4.2

SURFACE ANATOMY

Surface fe at ure s. • The um bilicus is where the um bilical cord entered the fetus and indicates the anterior level of the T10 derm atom e. Typ ically, the um bilicus lies at the level of the intervertebral disc between the L3 and L4 vertebrae. • The linea alba is a brous band form ed by the fusion of the rig ht and left abdom inal aponeuroses between the xiphoid process and the pubic sym physis dem arcated super cially by a m idline vertical skin groove.

• A curved skin groove, the linea sem ilunaris, dem arcates the lateral bord er of the right and left rectus abdom inis m uscles and rectus sheath. • In lean individuals with good m uscle developm ent, three to four transverse skin grooves overlie the tendinous intersections of the rectus abdom inis m uscle. • The site of the inguinal ligament is indicated by a skin crease, the inguinal groove, just inferior and parallel to the ligament, marking the division between the anterolateral abdominal wall and the thigh.

ANTEROLATERAL ABDOMINAL WALL Median plane

Transumbilical plane

RLQ

LUQ

RL RI

LLQ

A. Anterior View

291

Midclavicular lines

RH RUQ

Ab d o m e n

E U

P

LH Subcostal plane

LL LI

Transtubercular plane

B. Anterior View

Abdominal Quadrants Right upper quadrant (RUQ) Left upper quadrant (LUQ) Right lower quadrant (RLQ) Left lower quadrant (LLQ)

Right upper quadrant (RUQ)

Left upper quadrant (LUQ)

Liver: right lobe Gallbladder Stomach: pylorus Duodenum: parts 1–3 Pancreas: head Right suprarenal gland Right kidney Right colic (hepatic) flexure Ascending colon: superior part Transverse colon: right half

Liver: left lobe Spleen Stomach Jejunum and proximal ileum Pancreas: body and tail Left kidney Left suprarenal gland Left colic (splenic) flexure Transverse colon: left half Descending colon: superior part

ABDOMINAL REGIONS AND QUADRANTS A. Quadrants. B. Regions. It is im portant to know what org ans are located in each abdom inal region or quad rant so that one knows where to auscultate, percuss, and palpate them and to record the locations of ndings during a physical exam . The six com m on causes of ab d o m in al p ro t rusio n begin with the letter F: food, uid, fat, feces, atus, and fetus. Eversion of the um bilicus m ay be a sign of increased intra-abdom inal pressure, usually resulting from ascites (abdom inal accum ulation of serous uid in the peritoneal cavity), or a large m ass (e.g., a tum or, fetus, or enlarged organ such as the liver [hepatom egaly]).

Abdominal Regions Right hypochondriac (RH) Epigastric (E) Left hypochondriac (LH) Right lateral (lumbar) (RL) Umbilical (U)

Left lateral (lumbar) (LL) Right inguinal (groin) (RI) Pubic (hypogastric) (P) Left inguinal (groin) (LI)

Right lower quadrant (RLQ)

Left lower quadrant (LLQ)

Cecum Appendix Most of ileum Ascending colon: inferior part Right ovary Right uterine tube Right ureter: abdominal part Right spermatic cord: abdominal part Uterus (if enlarged) Urinary bladder (if very full)

Sigmoid colon Descending colon: inferior part Left ovary Left uterine tube Left ureter: abdominal part Left spermatic cord: abdominal part Uterus (if enlarged) Urinary bladder (if very full)

4.3 Warm hands are im portant when palpating the abdom inal wall because cold hands m ake the anterolateral abdom inal m uscles tense, producing involuntary m uscle spasm s known as guarding. Intense guarding, boardlike re exive m uscular rigidity that cannot be willfully suppressed, occurs during palpation when an organ (such as the appendix) is in am ed and in itself constitutes a clinically signi cant sign of acut e ab d om en . The involuntary m uscular spasm s attem pt to protect the viscera from pressure, which is painful when an abdom inal infection is present. The com m on nerve supply of the skin and m uscles of the wall explains why these spasm s occur.

292

Ab d o m e n

ANTEROLATERAL ABDOMINAL WALL

C2

C3 C5 C6

C4 C5 T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12

S2

L1 S3

L2 S3 S4

Lateral View

4.4

DERMATOMES

The thoraco-ab dom inal (T7–T11) nerves run between the external and internal obliq ue m uscles to supp ly sensory innervation to the overlying skin. The T10 nerve supp lies the reg ion of the um bilicus. The subcostal nerve (T12) runs along the inferior border of the 12th rib to supply the skin over the anterior superior iliac spine

and hip. The iliohypogastric nerve (L1) innervates the skin over the iliac crest and lower pubic region and the ilio-inguinal nerve (L1) innervates the skin of the m edial aspect of the thigh, the scrotum or labium m ajus, and m ons pubis.

ANTEROLATERAL ABDOMINAL WALL

Ab d o m e n

293

Internal thoracic artery Musculophrenic artery

T4

Thoraco-abdominal nerves:

Superior epigastric artery

T7

T5

T8

10th posterior intercostal artery

T6

T9

External oblique

T10

11th posterior intercostal artery

T11

T7 T8

Subcostal nerve (T12)

Internal oblique Subcostal artery Transversus abdominis Inferior epigastric artery Deep circumflex iliac artery Superficial epigastric artery

Iliohypogastric nerve (L1)

T10

Ilio-inguinal nerve (L1)

T11

Lateral abdominal cutaneous branch

T12

Anterior abdominal cutaneous branch

Superficial circumflex iliac artery

T9

L1

External iliac artery Femoral artery Transversalis fascia Anterior View

ARTERIES AND NERVES OF ANTEROLATERAL ABDOMINAL WALL The skin and m uscles of the anterolateral abdom inal wall are sup plied m ainly by the: • Thoraco-ab dom inal nerves: distal, abdom inal p arts of the anterior ram i of the inferior six thoracic spinal nerves (T7–T11), which have m uscular b ranches and anterior and lateral abdom inal cutaneous branches. The anterior abdom inal cutaneous b ranches pierce the rectus sheath a short distance from the m edian p lane, after the rectus abdom inis m uscle has been supplied. Spinal nerves T7–T9 sup ply the skin superior to the um bilicus; T10 innervates the skin around the um bilicus. • Spinal nerve T11, plus the cutaneous branches of the subcostal (T12), iliohypogastric, and ilio-inguinal (L1) nerves: supply the skin inferior to the um bilicus. • Subcostal nerve: large anterior ram us of spinal nerve T12. The b lood vessels of the anterolateral abdom inal wall are the: • Sup erior epigastric vessels and branches of the m usculop hrenic vessels, the term inal branches of the internal thoracic vessels.

4.5

• Inferior epigastric and deep circum ex iliac vessels from the external iliac vessels. • Super cial circum ex iliac and super cial epigastric vessels from the fem oral artery and great saphenous vein. • Posterior intercostal vessels in the 11th intercostal space and anterior branches of subcostal vessels. In cisio n al n e rve in jury. The inferior thoracic spinal nerves (T7–T12) and the iliohypogastric and ilio-inguinal nerves (L1) approach the abdom inal m usculature separately to provide the m ultisegm ental innervation of the abdom inal m uscles. Thus, they are distributed across the anterolateral abdom inal wall, where they run oblique but m ostly horizontal courses. They are susceptible to injury in surgical incisions or from traum a at any level of the abdom inal wall. Injury to them m ay result in weakening of the m uscles. In the inguinal region, such a weakness m ay predispose an individual to developm ent of an inguinal hernia.

294

Ab d o m e n

ANTEROLATERAL ABDOMINAL WALL

Intercostobrachial nerves (T2) Pectoralis major

Long thoracic nerve

Nipple

Serratus anterior

Latissimus dorsi

Anterior branches of lateral abdominal cutaneous branches (T6, T7, T8)

Posterior branches of lateral abdominal cutaneous branches of thoraco-abdominal nerves

External oblique Aponeurosis of external oblique (part of anterior wall of rectus sheath) Umbilicus

Lateral cutaneous branch of iliohypogastric nerve (L1) Lateral cutaneous branch of subcostal nerve (T12)

Anterior superior iliac spine

Lateral View

4.6

ANTEROLATERAL ABDOMINAL WALL, SUPERFICIAL DISSECTION

The m uscular p ortion of the external oblique m uscle interd igitates with slips of the serratus anterior m uscle, and the aponeurotic p ortion contributes to the anterior wall of the rectus sheath. The anterior and p osterior branches of the lateral abdom inal cutaneous branches of the thoraco-abdom inal nerves course super cially in the subcutaneous tissue. • Um b ilical h e rn ias are usually sm all protrusions of extraperitoneal fat and/ or peritoneum and om entum and som etim es bowel. They result from increased intra-abdom inal p ressure in

the presence of weakness or incom plete closure of the anterior abdom inal wall after ligation of the um bilical cord at birth, or m ay be acquired later, m ost com m only in wom en and obese people. • The lines along which the bers of the abdom inal aponeurosis interlace (see Fig. 4.10A, B, and D) are also potential sites of herniation. These gap s m ay be congenital, the result of the stresses of obesity and aging, or the consequence of surgical or traum atic wounds.

Ab d o m e n

ANTEROLATERAL ABDOMINAL WALL

295

To parasternal lymph nodes

Subcutaneous tissue

Axillary vein

Axillary lymph nodes

To anterior diaphragmatic lymph nodes Thoraco-epigastric vein

Transumbilical plane

Superficial epigastric vein Superficial inguinal lymph nodes

Femoral vein

A. Anterior View Thoraco-epigastric vein Superficial epigastric vein

B. Anterior View

LYMPHATIC DRAINAGE AND SUBCUTANEOUS (SUPERFICIAL) VENOUS DRAINAGE OF ANTEROLATERAL ABDOMINAL WALL A. Overview. • The skin and subcutaneous tissue of the abdom inal wall are served by an intricate subcutaneous venous plexus, draining superiorly to the internal thoracic vein m edially and the lateral thoracic vein laterally, and inferiorly to the super cial and inferior epigastric veins, tributaries of the fem oral and external iliac veins, respectively. • Super cial lym phatic vessels accom pany the subcutaneous veins; those superior to the transum bilical plane drain m ainly to the axillary lym ph nodes; however, a few drain to the parasternal lym ph nodes. Super cial lym phatic vessels inferior to the transum bilical plane drain to the super cial inguinal lym ph nodes.

4.7

B. Enlarg em ent of subcutaneous veins. • Lip o suct io n is a surgical m ethod for rem oving unwanted subcutaneous fat using a percutaneously placed suction tube and high vacuum pressure. The tubes are inserted subderm ally through sm all skin incisions. • When ow in the superior or inferior vena cava is obstructed, anastom oses between the tributaries of these system ic veins, such as the thoraco-epigastric vein, m ay provide collat eral p at h ways by which the obstruction m ay be bypassed, allowing blood to return to the heart. The veins becom e enlarged and tortuous ( B).

296

Ab d o m e n

ANTEROLATERAL ABDOMINAL WALL

Serratus anterior

5th costal cartilage Anterior layer of rectus sheath

Anterior layer of rectus sheath

Rectus abdominis

Linea alba External oblique

Lateral abdominal cutaneous branches Anterior abdominal cutaneous branches

External oblique

Tendinous intersection Aponeurosis of external oblique Anterior superior iliac spine

Fatty layer of subcutaneous tissue Superficial circumflex iliac artery and vein Superficial epigastric artery and vein Superficial inguinal ring External pudendal artery

Membranous deep layer of subcutaneous tissue Intercrural fibers Medial and lateral crura Ilio-inguinal nerve Spermatic cord

Great saphenous vein

A. Anterior View

4.8

ANTERIOR ABDOMINAL WALL

A. Super cial dissection demonstrating the relationship of the cutaneous nerves and super cial vessels to the musculoaponeurotic structures. The anterior wall of the left rectus sheath is re ected, revealing the rectus abdominis muscle, segmented by tendinous intersections. • After the T7 to T12 spinal nerves sup ply the m uscles, their anterior abdom inal cutaneous branches em erge from the rectus abdom inis m uscle and pierce the anterior wall of its sheath. • The three sup er cial ing uinal branches of the fem oral artery (super cial circum ex iliac artery, super cial epigastric artery,

and external pudendal artery) and the g reat saphenous vein lie in the fatty layer of subcutaneous tissue. • The b ers of the external obliq ue aponeurosis separate into m edial and lateral crura, which, with the intercrural bers that unite them , form the sup er cial inguinal ring. The sperm atic cord of the m ale (shown here), or round ligam ent of the fem ale, exits the inguinal canal through the super cial inguinal ring along with the ilio-inguinal nerve.

ANTEROLATERAL ABDOMINAL WALL

Ab d o m e n

297

Pectoralis major Serratus anterior

Rectus abdominis

7th costal cartilage Superior epigastric artery Anterior layer of rectus sheath

Posterior wall of rectus sheath

Linea alba Transversus abdominis Anterior abdominal branches of anterior rami External oblique (cut edges) Internal oblique (cut edges) Internal oblique Anterior superior iliac spine (ASIS) Transversalis fascia

Arcuate line Inferior epigastric artery

Iliohypogastric nerve Ilio-inguinal nerve

Rectus abdominis

Opened inguinal canal

Conjoint tendon

Saphenous opening

Coverings of spermatic cord

Great saphenous vein

B. Anterior View

ANTERIOR ABDOMINAL WALL (continued ) B. Deep dissection. On the right side of the specim en, m ost of the external oblique m uscle is excised. On the left, the internal oblique m uscle is divided and the rectus abdom inis m uscle is excised, revealing the posterior wall of the rectus sheath. • The bers of the internal oblique muscle run horizontally at the level of the anterior superior iliac spine (ASIS), obliquely upward superior to the ASIS, and obliquely downward inferior to the ASIS. • The arcuate line is at the level of the ASIS; inferior to the line, transversalis fascia lies im mediately posterior to the rectus abdom inis m uscle.

4.8 • Initially, the anterior abdom inal branches of the anterior ram i course between the internal oblique and transversus abdom inis m uscles. • The anastom osis between the superior and inferior epigastric arteries indirectly unites the subclavian artery of the upper lim b to the external iliac arteries of the lower lim b. The anastom osis can b ecom e functionally p atent in response to slowly d e ve lo p in g o cclusio n o f t h e ao rt a.

Ab d o m e n

298

8

ANTEROLATERAL ABDOMINAL WALL 7

7

7

8

8

9

9

9

10

10

Aponeurosis of external oblique (contributing to anterior layer of rectus sheath)

External oblique (A)

10

A

Internal nternal oblique (B)

Aponeurosis of internal oblique (contributing to anterior and posterior layers of rectus sheath) A

Iliac crest

A

B

Aponeurosis of transversus abdominis (contributing to posterior layer of rectus sheath) B A

Transversus abdominis

Inguinal ligament

Femur

A. Lateral View

B. Lateral View

C. Lateral View 6 7

4

8

Xiphoid process

5 A

10 11

A

L3

D

Tendinous intersection

Tendinous intersection D

Rectus sheath (anterior layer) removed Inguinal ligament

Pyramidalis

Pubic crest

Pubic symphysis

D. Anterior View

4.9

D

L2

Linea alba A

9

L1

Rectus abdominis (D)

A

5

E. Lateral View

MUSCLES OF ANTEROLATERAL ABDOMINAL WALL

A. External obliq ue. B. Internal oblique. C. Transversus abdom inis. D. and E. Rectus abdom inis and pyram idalis.

TABLE 4.1

a

PRINCIPAL MUSCLES OF ANTEROLATERAL ABDOMINAL WALL

Musclesa

Origin

Insertion

Innerva tion

External oblique (A)

External surfaces of 5th–12th ribs

Linea alba, pubic tubercle, and anterior half of iliac crest

Thoraco-abdominal nerves (anterior Compresses and supports abdominal viscera; rami of T7–T11) and subcostal nerve exes and rotates trunk

Internal oblique (B)

Thoracolumbar fascia, anterior two thirds of iliac crest, and connective tissue deep to inguinal ligament

Inferior borders of 10th–12th ribs, linea alba, and pubis via conjoint tendon

Transversus abdominis (C)

Internal surfaces of 7th–12th costal cartilages, thoracolumbar fascia, iliac crest, and connective tissue deep to inguinal ligament (iliopsoas fascia)

Linea alba with aponeurosis of internal oblique, pubic crest, and pectin pubis via conjoint tendon

Rectus abdominis (D)

Pubic symphysis and pubic crest

Xiphoid process and 5th–7th costal cartilages

Thoraco-abdominal nerves (anterior rami of T7–T11), subcostal nerve, and rst lumbar nerve

Thoraco-abdominal nerves (T7–T11) and subcostal nerve

Action(s)

Compresses and supports abdominal viscera (with external oblique ipsilaterally, internal oblique contralaterally) Flexes trunk and compresses abdominal viscera b; stabilizes and controls tilt of pelvis

Approximately 80% of people have a pyramidalis muscle, which is located in the rectus sheath anterior to the most inferior part of the rectus abdominis. It extends from the pubic crest of the hip bone to the linea alba. This small muscle tenses the linea alba. b In so doing, these muscles act as antagonists of the diaphragm to produce expiration.

Ab d o m e n

ANTEROLATERAL ABDOMINAL WALL

299

D Aponeurosis of right external oblique Right external oblique

C

Aponeurosis of left external oblique

E

Left external oblique Linea alba

Anterior View Showing Location of Sections C–E

Umbilical ring Fatty layer of subcutaneous tissue (Camper fascia)

External oblique Internal oblique

A. Anterior View

Transversus abdominis Skin

Aponeurosis of external oblique

Linea alba Internal oblique

B. Anterior View

Parietal peritoneum

C. Longitudinal Section

Investing (deep) fascia: Deep Intermediate Superficial

D.

Extraperitoneal fat

Membranous layer of subcutaneous tissue (Scarpa fascia)

Aponeurosis of internal oblique

External oblique

Transversalis fascia

Transversus abdominis Parietal peritoneum Internal oblique Extraperitoneal fat External oblique Transversalis fascia Rectus abdominis Aponeurosis of transversus abdominis Aponeurosis of internal oblique

Skin

Fatty layer of subcutaneous tissue

Aponeurosis of external oblique Rectus sheath

Linea alba Membranous layer of subcutaneous tissue

E.

STRUCTURE OF ANTEROLATERAL ABDOMINAL WALL

4.10

A. Interdigitation of the aponeuroses of the right and left external oblique m uscles. B. Interdigitation of the aponeuroses of the contralateral external and internal oblique m uscles. C–E. Layers of the abdom inal wall and the rectus sheath.

Transverse Sections

Ab d o m e n

300

INGUINAL REGION

Linea alba

External oblique

Aponeurosis of external oblique Anterior superior iliac spine

Intercrural fibers

Inguinal ligament

Superficial inguinal ring

Lateral crus

Medial crus Acetabular labrum

Lacunar ligament Pubic symphysis

Reflected ligament

A. Anterior View

Pubic tubercle Pubic crest

External oblique Aponeurosis of external oblique Potential space deep to membranous layer Anterior superior iliac spine

Umbilicus

Plane of section in part C

Inguinal ligament

Membranous layer of subcutaneous tissue (Scarpa fascia)

Continuity with fascia lata Fascia lata Saphenous opening Skin

B. Anterior View

4.11

Continuity with superficial fascia of penis (cut) Spermatic cord Continuity with dartos tunic of scrotum (cut) Attachment to posterior edge of perineal membrane

Skin Fatty layer of subcutaneous tissue (Camper fascia) Aponeurosis of external oblique Spermatic cord “Gutter” (floor of inguinal canal) Inguinal ligament Superior ramus of pubis Fascia lata Subcutaneous tissue of thigh

C. Sagittal Section

INGUINAL REGION OF MALE I

A. Form ations of the ap oneurosis of the external ob liq ue m uscle. B. and C. Mem branous (deep) layer of subcutaneous tissue. Inferior to the um b ilicus, the sub cutaneous tissue is com p osed of two layers: a sup er cial fatty layer and a deep m em branous layer. Laterally, the m em b ranous layer fuses with the fascia lata of the thigh about a nger’s breadth inferior to the inguinal ligam ent. Medially, it fuses with the linea alba and pubic sym physis in the

m idline, and inferiorly, it continues as the m em branous layer of the sub cutaneous tissue of the p erineum and p enis and the d artos fascia of the scrotum . The inferior m argin of the external oblique ap oneurosis is thickened and turned internally form ing the ing uinal ligam ent. The sup erior surface of the in-turning inguinal ligam ent form s a shallow trough or “gutter” that is the oor of the ing uinal canal.

INGUINAL REGION

Ab d o m e n

301

External oblique

Internal oblique

Linea alba Anterior layer of rectus sheath

Iliohypogastric nerve Conjoint tendon

Ilio-inguinal nerve

Reflected ligament Aponeurosis of external oblique Fundiform ligament of penis

Inguinal ligament

Medial crus

Cremaster muscle

Intercrural fibers

Of aponeurosis of external oblique

Lateral crus

Saphenous opening (falciform margin)

Inguinal lymph nodes Superficial inguinal ring

A. Anterior View Spermatic cord (cut ends)

External oblique

Internal oblique

Rectus abdominis

Aponeurosis of internal oblique Aponeurosis of external oblique (cut edges) Slips of cremaster muscle Spermatic cord

B. Anterior View

INGUINAL REGION OF MALE II

4.12

A. Internal oblique and cremaster muscle. Part of the aponeurosis of the external oblique m uscle is cut away, and the spermatic cord is cut short. B. Schematic illustration. • The crem aster fascia covers the sperm atic cord. Crem aster m uscle is dispersed within the crem asteric fascia. • The re ected ligam ent is form ed by aponeurotic bers of the external oblique m uscle and lies anterior to the conjoint tendon. The conjoint tend on is form ed by the fusion of the inferior m ost parts of the aponeurosis of the internal obliq ue and transversus abdom inis m uscles. • The cutaneous branches of the iliohypogastric and ilio-inguinal nerves (L1) course between the internal and external oblique m uscles and m ust be avoided when an ap p e n d e ct o m y (g rid iro n ) in cisio n is m ade in this region.

Ab d o m e n

302

INGUINAL REGION

Investing fascia Internal oblique

Iliohypogastric nerve Branches of deep circumflex iliac artery and vein Transversus abdominis

Aponeurosis of external oblique (cut edge)

Ilio-inguinal nerve Internal oblique Aponeurosis of internal oblique

Transversalis fascia

Inferior epigastric artery and vein

Aponeurosis of external oblique

Transversalis fascia

Cremaster muscle Conjoint tendon Location of deep inguinal ring

Pubic tubercle Cremasteric artery Cremasteric vein

Internal spermatic fascia covering spermatic cord

Anterior View

4.13

INGUINAL REGION OF MALE III

The internal obliq ue m uscle is re ected, and the sp erm atic cord is retracted. • The internal obliq ue m uscle portion of the conjoint tendon is attached to the pubic crest, and the transversus abdom inis portion to the pectineal line.

TABLE 4.2

• The iliohypogastric and ilio-inguinal nerves (L1) supply the internal obliq ue and transversus abdom inis m uscles. • The transversalis fascia is evaginated to form the tubular internal sp erm atic fascia. The m outh of the tube, called the deep inguinal ring, is situated lateral to the inferior ep igastric vessels.

BOUNDARIES OF INGUINAL CANAL

Bounda ry

Deep Ring/La tera l Third

Middle Third

La tera l Third/Super cia l Ring

Posterior wall

Transversalis fascia

Transversalis fascia

Inguinal falx (conjoint tendon) plus re ected inguinal ligament

Anterior wall

Internal oblique plus lateral crus of aponeurosis of external oblique

Aponeurosis of external oblique (lateral crus and intercrural bers)

Aponeurosis of external oblique (intercrural bers), with fascia of external oblique continuing onto cord as external spermatic fascia

Roof

Transversalis fascia

Musculo-aponeurotic arches of internal oblique and transversus abdominis

Medial crus of aponeurosis of external oblique

Floor

Iliopubic tract

Inguinal ligament

Lacunar ligament

INGUINAL REGION

Ab d o m e n

303

Transversus abdominis and aponeurosis Internal oblique Testicular vessels

Spermatic cord

Ductus deferens

Anterior superior iliac spine

Transversus abdominis

Transversus abdominis

Inguinal ligament

Location of deep inguinal ring

Transversalis fascia Extraperitoneal fat

Inferior epigastric artery Inferior epigastric vein

Femoral branch of genitofemoral nerve Deep circumflex iliac vein

Pubic branches

Deep circumflex iliac artery External iliac artery

Conjoint tendon

External iliac vein

Pubic tubercle

Fascia lata

Cremasteric artery

Femoral artery Femoral vein

A. Anterior View

Margin of saphenous opening

Deep inguinal lymph nodes in femoral canal

External oblique Internal oblique Aponeurosis of internal oblique (cut edges) Rectus abdominis Aponeurosis of external oblique (cut edge) Transversus abdominis and aponeurosis Spermatic cord Transversalis fascia Conjoint tendon Inguinal ligament Pubic tubercle

B. Anterior View

INGUINAL REGION OF MALE IV

4.14

A. The ing uinal p art of the transversus abdom inis m uscle and transversalis fascia is p artially cut away, the sp erm atic cord is excised, and the ductus deferens is retracted. B. Schem atic illustration. • The deep inguinal ring is located superior to the inguinal ligam ent at the m idpoint between the anterior superior iliac spine and pubic tubercle. • The external iliac artery has two branches, the deep circum ex iliac and inferior ep igastric arteries. Note also the crem asteric artery and p ubic branch arising from the latter.

304

Ab d o m e n

INGUINAL REGION

Anterior superior iliac spine

Fatty layer of subcutaneous tissue

Membranous layer of subcutaneous tissue Intercrural fibers Femoral branch of genitofemoral nerve Superficial inguinal ring Medial crus of aponeurosis of exterior oblique Fat pad Pubic tubercle

Artery of round ligament

Labium majus

Site of inguinal ligament

Pudendal cleft

Lateral crus of aponeurosis of exterior oblique Genital branch of genitofemoral nerve

A. Anterior View

4.15

Round ligament of uterus

INGUINAL CANAL OF FEMALE

Pro g re ssive d isse ct io n s o f t h e fe m ale in g uin al can al. • The sup er cial inguinal ring is sm all ( A) . Passing through the sup er cial inguinal ring are the round ligam ent of the uterus, a closely app lied fat pad, the genital branch of the genitofem oral nerve, and the artery of the round ligam ent of the uterus ( B) .

• The round ligam ent breaks up into strands as it leaves the inguinal canal and approaches the labium m ajus. The ilio-inguinal nerve m ay also pass through the super cial inguinal ring ( C) . • The external iliac artery and vein are exposed deep to the inguinal canal by excising the transversalis fascia ( D) .

INGUINAL REGION

Ab d o m e n

305

Membranous layer of subcutaneous tissue

Aponeurosis of external oblique

Internal oblique

Femoral branch of genitofemoral nerve

Cremaster muscle

Fat pad

Inguinal ligament

Strands of round ligament of uterus

B

Internal oblique

Deep inguinal ring Transversalis fascia Round ligament of uterus Strands of round ligament Genital branch of genitofemoral nerve

Anterior Views

C

Internal oblique and aponeurosis Transversus abdominis

Transversalis fascia (cut)

Deep circumflex iliac artery and vein

Conjoint tendon

External iliac artery

Pubic tubercle

Inferior epigastric artery and veins External iliac vein Inguinal ligament

D

INGUINAL CANAL OF FEMALE (continued )

4.15

Ab d o m e n

306

INGUINAL REGION

External oblique (cut edges)

12th thoracic nerve Inferior epigastric artery Iliohypogastric nerve

Internal oblique Posterior wall of rectus sheath Iliohypogastric nerve Ilio-inguinal nerve Fascia lata

Internal oblique Transversus abdominis Ascending branch of deep circumflex iliac artery Femoral branch of genitofemoral nerve Deep inguinal ring Inferior epigastric artery

Femoral branches of genitofemoral nerve Edge of saphenous opening Femoral sheath Genital branch of genitofemoral nerve to scrotal wall Great saphenous vein

Genital branch of genitofemoral nerve to cremaster Cremasteric artery Conjoint tendon Internal spermatic fascia Cremaster External spermatic fascia

A. Anterior View

Internal oblique (reflected) Aponeurosis of external oblique (cut edge)

Internal oblique and aponeurosis

Transversus abdominis Arch of transversus abdominis Transversalis fascia Internal spermatic fascia Cremaster muscle and fascia

Conjoint tendon Cremaster muscle (in cremaster fascia) Suspensory ligament of penis

Conjoint tendon External spermatic fascia

Cremaster muscle and fascia Internal spermatic fascia Tunica vaginalis (parietal layer) Epididymis (head)

B. Anterior View

4.16

INGUINAL CANAL, SPERMATIC CORD, AND TESTIS

Tunica vaginalis (visceral layer) covering testis

Ab d o m e n

INGUINAL REGION

Testicular veins

307

Testicular artery Ductus deferens

Internal spermatic fascia Cremaster muscle within cremasteric fascia

Spermatic cord

External spermatic fascia Testicular artery Lobules of epididymis

Pampiniform plexus of veins

Ductus deferens

Efferent ductules of testis

Epididymis External spermatic fascia Cremaster muscle and fascia

Tunica vaginalis (parietal layer)

Internal spermatic fascia

Tunica vaginalis (visceral layer) covering testis

C. Lateral View

D. Anterior View

Key for E

Subcutaneous tissue (superficial fascia)

External oblique External spermatic fascia

Skin

Internal oblique Cremaster muscle &cremasteric fascia

Ductus deferens Testicular vessels

Spermatic cord

Transversus abdominis Transversalis fascia Internal spermatic fascia Peritoneum Tunica vaginalis (parietal and visceral layers)

Epididymis Layers of tunica vaginalis

Parietal Visceral

Cavity of tunica vaginalis

Testis

Skin Dartos muscle and fascia

Scrotum

E. Schematic Illustration

INGUINAL CANAL, SPERMATIC CORD, AND TESTIS (continued ) A. Dissection of inguinal canal. B. Dissection of inguinal region and coverings of the sperm atic cord and testis. C–E. Coverings

4.16

of sp erm atic cord and testis. The cavity of the tunica vaginalis is norm ally a p otential space.

Ab d o m e n

308

INGUINAL REGION Male

Primordial testis (in retroperitoneal connective tissue)

Kidney Primordial ovaries

Ureter

Gubernaculum

Ductus deferens

Testis

Female

Paramesonephric duct Developing kidney

Peritoneum

Processus vaginalis

Anterior View

Gubernaculum Primordial scrotum

Future deep inguinal ring Superficial inguinal ring

Mesonephric duct

Upper gubernaculum (inguinal fold–becomes ligament of ovary)

Lower gubernaculum (becomes round ligament of uterus) Peritoneum

Body of right pubis

D. 2 Months

Diagrammatic oblique sagittal section to right of midline

A. Seventh Week Kidney Ureter Ovary Ligament of ovary Round ligament of uterus

Gubernaculum

Deep inguinal ring

Superficial inguinal ring

Labia majora

E. 15 Weeks

Site of deep inguinal ring Anterior View

Gubernaculum Processus vaginalis

4.17

Diagrammatic oblique sagittal section to right of midline

B. Seventh Month

Ductus deferens

Spermatic cord

Ductus deferens Tunica vaginalis testis Testis

C. Ninth Month

Anterior View Diagrammatic oblique sagittal section to right of midline

RELOCATION OF GONADS

The inguinal canals in fem ales are narrower than those in m ales, and the canals in infants of both sexes are shorter and m uch less oblique than in adults. For a com p lete descrip tion of the em bryology of the inguinal region, see Moore et al. (2012). The fetal testes relocate from the dorsal abdom inal wall in the superior lum bar region to the deep inguinal rings during the 9th to 12th fetal weeks. This m ovem ent probably results from the growth of the vertebral colum n and pelvis. The m ale gubernaculum , attached to the caudal pole of the testis and accom p anied by an outpouching of peritoneum , the p rocessus vaginalis, projects into the scrotum . The testis passes posterior to the processus vaginalis. The inferior rem nant of the p rocessus vaginalis form s the tunica vaginalis covering the testis. The ductus deferens, testicular vessels, nerves, and lym phatics accom pany the testis. The nal descent of the testis usually occurs before or shortly after birth. The fetal ovaries also relocate from the dorsal abdom inal wall in the superior lum bar region during the 12th week but pass into the lesser pelvis. The fem ale gubernaculum attaches to the caudal pole of the ovary and projects into the labia m ajora, attaching en route to the uterus; the part passing from the uterus to the ovary form s the ovarian ligam ent, and the rem ainder of it becom es the round ligam ent of the uterus. Because of the attachm ent of the ovarian ligam ents to the uterus, the ovaries do not relocate to the inguinal region; however, the round ligam ent passes through the inguinal canal and attaches to the subcutaneous tissue of the labium m ajus.

Ab d o m e n

INGUINAL REGION

Direct (acquired) inguinal hernia Testicular vessels entering spermatic cord

Indirect (congenital) inguinal hernia

Inguinal triangle

Lateral umbilical fold Ductus deferens

309

Medial umbilical fold

Inferior epigastric vessels Median umbilical fold

Transversalis fascia

Transversus abdominis Internal oblique

Peritoneum

External oblique Deep inguinal ring Ilio-inguinal nerve Inguinal ligament Herniating bowel passes MEDIAL to inferior epigastric vessels, pushing through peritoneum and transversalis fascia in inguinal triangle to enter inguinal canal.

Herniating bowel passes LATERAL to inferior epigastric vessels to enter deep inguinal ring. Deep inguinal ring Conjoint tendon (inguinal falx)

Superficial inguinal ring Hernial sac (parallels spermatic cord)

Loop of intestine inside cord Hernial sac (within spermatic cord)

Spermatic cord

4.18

COURSE OF DIRECT AND INDIRECT INGUINAL HERNIAS An in g uin al h e rn ia is a protrusion of parietal peritoneum and viscera, such as the sm all intestine, throug h the abdom inal wall in the inguinal region. There are two m ajor categories of inguinal

TABLE 4.3

hernia: indirect and direct. More than two thirds are ind irect hernias, m ost com m only occurring in m ales.

CHARACTERISTICS OF INGUINAL HERNIAS

Cha ra cteristics

Direct (Acquired)

Indirect (Congenita l)

Predisposing factors

Weakness of anterior abdominal wall in inguinal triangle (e.g., owing to distended super cial ring, narrow conjoint tendon, or attenuation of aponeurosis in males 40 years of age)

Patency of processus vaginalis (complete or at least of superior part) in younger persons, the great majority of whom are males

Frequency

Less common (one third to one fourth of inguinal hernias)

More common (two thirds to three fourths of inguinal hernias)

Coverings at exit from abdominal cavity

Peritoneum plus transversalis fascia (lies outside inner one or two fascial coverings, parallel to cord)

Peritoneum of persistent processus vaginalis plus all three fascial coverings of cord/round ligament

Course

Usually traverses only medial third of inguinal canal, external and parallel to vestige of processus vaginalis

Traverses inguinal canal (entire canal if it is suf cient size) within processus vaginalis

Exit from anterior abdominal wall

Via super cial ring, lateral to cord; rarely enters scrotum

Via super cial ring inside cord, commonly passing into scrotum/labium majus

Ab d o m e n

310

TESTIS

Superficial (external) inguinal ring External spermatic fascia Testicular artery Ilio-inguinal nerve

Cremaster Genitofemoral nerve

Suspensory ligament of penis

Ductus deferens Deep dorsal vein of penis

Pampiniform plexus of veins

Dorsal artery and nerve of penis

Epididymis External spermatic fascia Testis

A.

Glans penis

Anterior View

Spermatic cord

4.19

SPERMATIC CORD, TESTIS, AND EPIDIDYMIS

A. Dissection of sperm atic cord. The subcutaneous tissue (dartos fascia) covering the p enis has b een rem oved and the deep fascia rendered transparent to dem onstrate the m edian deep dorsal vein and the bilateral dorsal arteries and nerves of the penis. On the specim en’s right, the coverings of the sperm atic cord and testis are re ected, and the contents of the cord are separated. The testicular artery has been separated from the pam piniform plexus of veins that surrounds it as it courses parallel to the ductus deferens. Lym phatic vessels and autonom ic nerve bers (not shown) are also present. B. The tunica vaginalis has been incised longitudinally to expose its cavity, surrounding the testis anteriorly and laterally, and extending between the testis and epididym is at the sinus of the ep ididym is. The epididym is is located posterolateral to the testis, that is, toward the right side of the right testis and the left side of the left testis. The app endices of the testis and epididym is m ay be ob served in som e specim ens. These structures are sm all rem nants of the em bryonic genital (param esonephric) duct.

Epididymis: Head

Appendices of epididymis

Appendix of testis

Body

Testis covered by visceral layer of tunica vaginalis

Sinus

Tail

B. Anterior View

Parietal layer of tunica vaginalis (cut edge) Gubernacular remnant

TESTIS

Ab d o m e n

311

Thoracic duct Cremasteric arteries Abdominal aorta

Cisterna chyli

Testicular artery

Pre-aortic nodes Artery of ductus deferens

Left testicular artery

Right testicular artery

Ductus deferens

Common iliac nodes

Lumbar (caval/aortic) nodes

External iliac nodes

Epididymis

Right common iliac artery

Superficial inguinal nodes

Tunica vaginalis (cut edges)

Femoral artery

A. Posterior View Ductus deferens Head of epididymis Efferent ductules Testis Rete testis Visceral layer Parietal layer

Lymphatic Drainage of:

Tunica vaginalis

Cavity of tunica vaginalis

Scrotum

Scrotum

C. Anterior View

Testis

Seminiferous tubule Tail Body

Tunica albuginea

of epididymis

B. Longitudinal Section of Tunica Vaginalis;

Testis Sectioned in Sagittal and Transverse Planes

BLOOD SUPPLY AND LYMPHATIC DRAINAGE OF TESTIS A. Blood sup ply. B. Internal structure. C. Lym p hatic drainage. Because the testes relocate from the p osterior ab d om inal wall into the scrotum d uring fetal d evelop m ent, their lym p hatic d rainag e d iffers from that of the scrotum , wh ich is an

4.20 outp ouching of the ab d om inal skin. Conseq uently, ca n ce r o f t h e t e st is m etastasizes initially to the lum b ar lym p h nod es, and ca n ce r o f t h e scro t u m m etastasizes initially to the sup er cial ing uinal lym p h nod es.

Ab d o m e n

312

PERITONEUM AND PERITONEAL CAVITY

Diaphragm

Round ligament of liver

Parietal peritoneum (cut edge) Falciform ligament

Umbilicus Para-umbilical veins

Para-umbilical vein

Transversalis fascia

Costodiaphragmatic recess

Parietal peritoneum External oblique Internal oblique

Posterior rectus sheath

Transversus abdominis

Arcuate line

Transversalis fascia (cut edge)

Rectus abdominis Inferior epigastric vessels

Parietal peritoneum (cut edge)

Deep inguinal ring

Lateral umbilical fold Medial umbilical fold

Deep circumflex iliac vessels

Lateral inguinal fossa

Iliopubic tract

Median umbilical fold

Testicular vessels Medial inguinal fossa (inguinal/Hesselbach triangle)

Femoral nerve

Iliacus

*

Femoral artery

Ductus deferens Urinary bladder

Femoral vein

Umbilical artery (obliterated distally as medial umbilical ligament)

Supravesical fossa

Obturator nerve and vessels Seminal gland

Ureter (cut end)

Tendinous arch of levator ani

Seminal vesicle

Obturator internus Posterior View

Prostate

Levator ani

Anterior recess of ischio-anal fossa

* Femoral ring/canal

4.21

POSTERIOR ASPECT OF THE ANTEROLATERAL ABDOMINAL WALL

Um bilical folds (m edian, m edial, and lateral) are re ections of the parietal peritoneum that are raised from the body wall by underlying structures. The m edian um bilical fold extends from the urinary bladder to the um bilicus and covers the m edian um bilical ligam ent (the rem nant of the urachus). The two m edial um bilical folds cover the m edial um bilical ligam ents (occluded rem nants of the fetal

um bilical arteries). Two lateral um bilical folds cover the inferior epigastric vessels. The supravesical fossae are between the m edian and m edial um bilical folds, the m edial inguinal fossae (inguinal triangles) are between the m ed ial and lateral um bilical folds, and the lateral inguinal fossae and deep inguinal rings are lateral to the lateral um bilical folds.

PERITONEUM AND PERITONEAL CAVITY

Ab d o m e n

313

Thoracic duct

Descending (thoracic) aorta

Azygos vein

Esophagus Pericardial sac

Inferior vena cava

Diaphragm Left lobe of liver Gastrosplenic ligament

Falciform ligament

Stomach Costodiaphragmatic recess Right lobe of liver Round ligament of liver (ligamentum teres)

Gastrocolic ligament

Fundus of gallbladder (more inferiorly placed here due to “tall” variation of liver)

*The term greater omentum

is often used as a synonym for the gastrocolic ligament, but it actually also includes the gastrosplenic and gastrophrenic ligaments, all of which have a continuous attachment to the greater curvature of the stomach.

External oblique Internal oblique Transversus abdominis Rectus abdominis

A. Anterior View

Diaphragm Falciform ligament

Coronary ligament (cut)

Round ligament of liver

Gastrophrenic ligament**

Liver surfaces: Diaphragmatic Visceral Gastrohepatic ligament* Arrow passing through omental foramen into omental bursa Hepatoduodenal ligament (containing portal triad)* Right colic flexure Ascending colon Greater omentum** (gastrocolic ligament) * Parts of lesser omentum B. Anterior View

Stomach Gastrosplenic ligament** Spleen Left colic flexure Transverse mesocolon Transverse colon (sectioned) Descending colon Gastrocolic ligament** Inferior recess of omental bursa ** Parts of greater omentum

ABDOMINAL CONTENTS AND PERITONEUM

4.22

A. Dissection. B. Com ponents of greater and lesser om entum .

Ab d o m e n

314

PERITONEUM AND PERITONEAL CAVITY

Diaphragm Bare area of liver Coronary ligament

Visceral peritoneum investing liver

Liver Superior recess of omental bursa

Lesser omentum Visceral peritoneum investing stomach

Descending aorta Omental bursa (lesser sac) Omental (epiploic) foramen

Stomach

Celiac trunk

Transverse mesocolon

Pancreas

Visceral peritoneum investing transverse colon

Superior mesenteric artery

Parietal peritoneum lining abdominopelvic wall

Pancreas Duodenum

Inferior recess of omental bursa

Mesentery of small intestine

Greater sac

Parietal peritoneum

Greater omentum

Bare area

Visceral peritoneum investing small intestine

Recto-uterine pouch

Uterus

Rectum

Urinary bladder Pubic symphysis Vagina

Key

Urethra

Greater sac Omental bursa (lesser sac)

Median Section

4.23

PERITONEAL FORMATIONS AND BARE AREAS

Various term s are used to describe the parts of the p eritoneum that connect organs with other organs or to the abdom inal wall and to

TABLE 4.4

describe the com partm ents and recesses that are form ed as a consequence. The arrow passes throug h the om ental (ep iploic) foram en.

TERMS USED TO DESCRIBE PARTS OF PERITONEUM

Term

De nition

Peritoneal ligament

Double layer of peritoneum that connects an organ with another organ or to the abdominal wall.

Mesentery

Double layer of peritoneum that occurs as a result of the invagination of the peritoneum by one or more organs and constitutes a continuity of the visceral and parietal peritoneum.

Omentum

Double-layered extension of peritoneum passing from the proximal duodenum and/or stomach and to adjacent organs. The greater omentum extends from the greater curvature of the stomach and the proximal duodenum; the lesser omentum from the lesser curvature.

Bare area

Every organ must have an area, the bare area, that is not covered with visceral peritoneum, to allow the entrance and exit of neurovascular structures. Bare areas are formed in relation to the attachments of mesenteries, omenta, and ligaments. Named bare areas (e.g., bare area of liver) are especially extensive.

Ab d o m e n

PERITONEUM AND PERITONEAL CAVITY

315

Diaphragm Lesser omentum

Liver Superior recess of omental bursa

Falciform ligament Subhepatic space

Descending aorta Pancreas

Key Supracolic compartment (greater sac)

Duodenum

Infracolic compartment (greater sac)

Mesentery of small intestine

Omental bursa (lesser sac)

Stomach Transverse mesocolon Transverse colon Inferior recess of omental bursa

Ileum

Greater omentum Jejunum

Rectovesical pouch

Parietal peritoneum Visceral peritoneum

Rectum

Urinary bladder

A. Right Lateral View

Superior recess of omental bursa

Liver

Liver

Lesser omentum Omental bursa (lesser sac)

Pancreas Stomach

Inferior recess of omental bursa

Duodenum

Transverse mesocolon Posterior abdominal wall

Greater omentum Posterior abdominal wall

Mesentery of small intestine

Ileum

B. Infant

Mesentery of small intestine

C. Adult Schematic Sagittal Sections, Lateral View

SUBDIVISIONS OF PERITONEAL CAVITY A. Sagittal section. B. In an infant, the om ental bursa (lesser sac) is an isolated part of the peritoneal cavity, lying posterior to the stom ach and extending superiorly between the liver and diaphragm (superior recess of the om ental bursa) and inferiorly between the layers of the greater om entum (inferior recess of the

4.24 om ental bursa). C. In an adult, after fusion of the layers of the greater om entum , the inferior recess of the om ental bursa now extends inferiorly only as far as the transverse colon. The arrows (red) pass from the g reater sac through the om ental (epip loic) foram en into the om ental bursa.

316

Ab d o m e n

PERITONEUM AND PERITONEAL CAVITY Inferior vena cava Diaphragm

Site of bare area of liver

Falciform ligament (cut edges) Left triangular ligament

Esophagus Hepatic portal vein Left gastric artery

Splenic vessels

Coronary ligament

Splenorenal ligament (cut edges) Right triangular ligament

Left kidney

Right suprarenal gland

Pancreas

Bile duct Hepatic artery proper

Root of transverse mesocolon (cut edges)

Middle colic vein Duodenum

Middle colic artery

Right kidney

Superior mesenteric artery Superior mesenteric vein

Root of mesentery of small intestine (cut edges)

Duodenojejunal junction

Right paracolic gutter

Left paracolic gutter

Site of bare area of ascending colon

Inferior mesenteric vein Inferior mesenteric artery Site of bare area of descending colon

Site of cecum Right ureter

Root of sigmoid mesocolon (cut edges)

Rectum Uterus

Left uterine tube Left ovary

Bladder

Left round ligament of uterus

A.

Anterior Views Supracolic compartment

Transverse mesocolon

Transverse colon

Left colic (splenic) flexure

Right colic flexure

4.25

POSTERIOR WALL OF PERITONEAL CAVITY

A. Roots of the p eritoneal re ections. The p eriton eal re ections from the p osterior ab d om inal wall (m esenteries and re ections surround ing b are areas of liver and second arily retrop eritoneal org ans) have b een cut at their roots, and the intrap eritoneal and second arily retrop eritoneal viscera have b een rem oved . The arrow (white) p asses throug h the om ental (ep ip loic) foram en. B. Sup racolic and infracolic com p artm ents of the g reater sac. The infracolic spaces and paracolic gutters are of clinical im portance because they determ ine the paths (black arrows) for the o w o f ascit ic uid wit h ch an g e s in p o sit ion , and the spread of intraperitoneal infections.

Phrenicocolic ligament

Tenia coli Root of mesentery of small intestine

Ascending colon

Descending colon

Right paracolic gutter

B.

Right infracolic space

Left Left infracolic paracolic space gutter

Infracolic compartment

Ab d o m e n

PERITONEUM AND PERITONEAL CAVITY

Portal triad 8th costal cartilage

Hepatic artery proper Hepatic portal vein Bile duct

Liver

317

Falciform ligament Round ligament of liver Rectus abdominis Lesser omentum 7th costal cartilage

Gallbladder (neck)

Stomach

Cystic duct

Common hepatic artery Celiac trunk

External oblique

Abdominal aorta

Costodiaphragmatic recess

Splenic artery

Omental (epiploic) foramen Inferior vena cava

Left suprarenal gland

Thoracic duct

Gastrosplenic ligament

Azygos vein

Spleen

Hepatorenal recess

Splenorenal ligament

T12

Right suprarenal gland

Left sympathetic trunk

Right crus of diaphragm

Left kidney

Right kidney Latissimus dorsi Parietal pleura

A. Inferior View

Diaphragm

Key Greater sac

T12 spinal nerve Spinal cord

Left lobe of liver

Erector spinae muscles

Omental bursa (lesser sac)

Rectus abdominis

Falciform ligament

External oblique

Proper hepatic artery

Stomach with air-fluid level

Hepatic portal vein

Pancreas Celiac trunk

Right lobe of liver

Left suprarenal gland

Inferior vena cava

Spleen T12

Right suprarenal gland

Abdominal aorta Left kidney Left crus of diaphragm

Right kidney Right crus of diaphragm

Plane of section (T12 vertebra) in A&B

Perirenal fat Spinous process

Deep back muscles

B. Transverse (Axial) CT Scan

TRANSVERSE SECTION AND AXIAL CT IMAGE THROUGH GREATER SAC AND OMENTAL BURSA • When bacterial contam ination occurs or when the gut is traum atically penetrated or rup tured as the result of infection and in am m ation, g as, fecal m atter, and bacteria enter the p eritoneal cavity. The result is infection and in am m ation of the p eritoneum , called p e rit o n it is. • Under certain pathological conditions such as peritonitis, the peritoneal cavity m ay be distended with ab norm al uid, ascit e s.

4.26

Widespread m etastases (spread) of cancer cells to the abdom inal viscera cause exudation (escape) of uid that is often blood stained. Thus, the peritoneal cavity m ay be distended with several liters of abnorm al uid. Surgical puncture of the peritoneal cavity for the aspiration of drainage of uid is called p arace n t e sis.

318

Ab d o m e n

PERITONEUM AND PERITONEAL CAVITY

Azygos vein and thoracic duct

Thoracic aorta

Lesser omentum

Diaphragm

Esophagus Lesser curvature of stomach

Right lobe of liver

Outline of liver (bold line) 7th rib Stomach Site of porta hepatis Greater curvature of stomach

Omental (epiploic) foramen Duodenum Free edge of lesser omentum Gallbladder Costodiaphragmatic recess Pyloric canal

Anastomosis between right and left gastroomental (epiploic) arteries

10th rib 11th costal cartilage

Transverse colon appearing in an unusual gap in the greater omentum

Gastrocolic ligament

A. Anterior View Lesser omentum

ANTERIOR

Portal triad in Hepatic artery hepatoduodenal Bile duct ligament Hepatic portal vein Peritoneal Cavity (P)

Hepatogastric ligament

Stomach

Visceral peritoneum (covering stomach) Gastrosplenic ligament

P P

Greater sac

Visceral peritoneum (covering spleen)

P

Omental bursa (lesser sac)

Parietal peritoneum

P

Spleen Omental (epiploic) foramen

P Splenorenal ligament

Parietal peritoneum Right kidney

B. Transverse Section

4.27

Inferior vena cava

Left kidney POSTERIOR

Abdominal aorta

STOMACH AND OMENTA

A. Lesser and greater om enta. The stom ach is in ated with air, and the left p art of the liver is cut away. The gallbladder, followed superiorly, leads to the free m argin of the lesser om entum and serves

as a guide to the om ental (epiploic) foram en, which lies posterior to that free m argin. B. Om ental bursa (lesser sac), schem atic transverse section. Arrow is traversing om ental foram en and bursa.

PERITONEUM AND PERITONEAL CAVITY Greater curvature of stomach

Portal triad

Ab d o m e n

319

Caudate lobe of liver Left suprarenal gland

Right dome of diaphragm

Left kidney Left dome of diaphragm Costodiaphragmatic recess

Right lobe of liver

Spleen

Costodiaphragmatic recess

Gastrosplenic ligament, cut edge (part of greater omentum) Splenic vein and artery Tail of pancreas

Gallbladder

Transverse mesocolon Transverse colon

Body of pancreas

Gastrocolic ligament, cut edge (part of greater omentum)

A. Anterior View Left dome of diaphragm Left triangular ligament

Liver

Adhesions

Stomach

Costodiaphragmatic recess

Esophageal opening

Spleen Phrenicocolic ligament

Pancreas (unusually short)

Left gastro-omental (epiploic) artery

Lesser omentum

Left kidney Splenic artery and vein Transverse colon Pylorus of stomach

Transverse mesocolon

Gastrocolic ligament (cut edge)

B. Anterior View

POSTERIOR RELATIONSHIPS OF OMENTAL BURSA (LESSER SAC) A. Op ened om ental bursa. The greater om entum has been cut along the greater curvature of the stom ach; the stom ach is reected sup eriorly. Peritoneum of the posterior wall of the bursa is partially rem oved. B. Stom ach bed. The stom ach is excised.

4.28

Peritoneum covering the stom ach bed and inferior p art of the kidney and pancreas is largely rem oved. Ad h e sio n s binding intraperitoneal organs, such as the sp leen to the diap hragm are pathological, but not unusual.

Ab d o m e n

320

Falciform ligament

PERITONEUM AND PERITONEAL CAVITY Caudate lobe

Superior recess of omental bursa

Left triangular ligament

Right lobe of liver Hepatic portal vein Left gastric vessels Quadrate lobe of liver

Lesser omentum (cut edge) Gastropancreatic fold

Rod passing from hepatorenal pouch through omental foramen into omental bursa

Stomach Common hepatic artery Splenic artery

Gallbladder

Pancreas (posterior to parietal peritoneum)

Duodenum Right kidney

Left gastro-omental vessels

Lesser omentum (cut edge)

Middle colic vessels Superior mesenteric vessels

Right colic (hepatic) flexure

Transverse mesocolon (lining posterior surface of inferior recess of omental bursa)

Transverse colon Stomach (cut edge)

Gastrocolic ligament (cut edge)

A. Anterior View Right gastro-omental vessels in gastrocolic ligament

4.29

Middle colic vessels

OMENTAL BURSA (LESSER SAC), OPENED

A. Dissection. B. Line of incision ( A) . The anterior wall of the om ental bursa, consisting of the stom ach, lesser om entum , anterior layer of the greater om entum , and vessels along the curvatures of the stom ach, has been sectioned sagittally. The two halves have b een retracted to the left and rig ht: the body of the stom ach on the left side, and the pyloric part of the stom ach and rst part of the duodenum on the right. The right kidney form s the posterior wall of the hepatorenal pouch (part of greater sac), and the pancreas lies horizontally on the posterior wall of the m ain com partm ent of the om ental bursa (lesser sac). The gastrocolic ligam ent form s the anterior wall and the lower part of the posterior wall of the inferior recess of the om ental bursa. The transverse m esocolon form s the up per part of the posterior wall of the inferior recess of the om ental bursa.

Liver Lesser omentum:

Stomach

Hepatogastric ligament Hepatoduodenal ligament

Gastrocolic ligament

Line of incision

B. Anterior View

Ab d o m e n

PERITONEUM AND PERITONEAL CAVITY

321

Superior recess of omental bursa Liver

Caudate lobe

Esophagus

Left triangular ligament

Esophageal branches Left gastric vein and artery Celiac trunk Spleen

Common hepatic artery

Stomach

Hepatic portal vein

Omental bursa

Right gastric artery and vein Gallbladder

Splenic artery and vein in splenorenal ligament

Splenic artery

Stomach (reflected to right)

Gastrocolic ligament Left gastro-omental vessels Splenic vein Pancreas Left renal vein

Neck of pancreas

Inferior mesenteric vein Left testicular vein Superior mesenteric vein Superior mesenteric artery

Right gastroomental vessels

Uncinate process of pancreas

Right colic vessels Head of pancreas

Middle colic artery and vein Accessory middle colic artery

Ileocolic vein

Anterior View

POSTERIOR WALL OF OMENTAL BURSA The parietal peritoneum of the posterior wall of the om ental bursa has been m ostly rem oved, and a section of the pancreas has been excised. The rod passes through the om ental foram en. • The celiac trunk gives rise to the left gastric artery, the sp lenic artery that runs tortuously to the left, and the com m on hepatic artery that runs to the right, passing anterior to the hepatic portal vein. • The hep atic p ortal vein is form ed p osterior to the neck of the pancreas by the union of the superior m esenteric and splenic

4.30 veins, with the inferior m esenteric vein joining at or near the angle of union. • The left testicular vein usually drains into the left renal vein. Both are system ic veins. • In am m at io n o f t h e p arie t al p e rit o n e um can occur due to an enlarged organ or b y the escape of uid from an organ. The area becom es in am ed and causes pain over the affected region. • Re b o un d t e n d e rn e ss is a pain that is elicited after pressure over the in am ed area is released.

Ab d o m e n

322

DIGESTIVE SYSTEM

Arteries Celiac Superior mesenteric Inferior mesenteric

Mouth Tongue Pharynx Larynx Trachea Esophagus

Liver

Stomach

Gallbladder Pylorus Duodenum

B. Anterior View

Pancreas Transverse colon

Veins Liver

Descending colon

Ascending colon Jejunum Ileum Cecum Appendix

Sigmoid colon

Hepatic portal vein

Hepatic portal Splenic Superior mesenteric Inferior mesenteric Direction of flow of blood

Rectum Anal canal

A. Diagrammatic Anterior View; Medial View of Bisected Head

C. Anterior View

4.31

ALIMENTARY SYSTEM

A. Overview. The alim entary system extends from the lips to the anus. Associated organs include the liver, gallbladder,

and pancreas. B. Overview of arterial sup ply. C. Overview of p ortal venous drainage.

Ab d o m e n

STOMACH

323

Cardial notch Esophagus

Esophagogastric junction

Fundus

Cardia

Cardial notch

s

Circular layer

tu

s Le a v cur

Pylorus

Left gastric artery and vein

Body

Pyloric canal re

ter a e Gr

t va r cu

Pyloric antrum

Oblique fibers Muscular layers Longitudinal layer

Lesser curvature

u

Duodenum

Fundus

Esophagus re

Angular incisure

er

Cardia

Hepatogastric ligament (lesser omentum)

Gastrosplenic ligament

Angular incisure

Short gastric vein and artery

Right gastric vein and artery

Body

Hepatoduodenal ligament (lesser omentum)

A. Anterior View

Greater curvature

Duodenum Pylorus

Left gastro-omental artery and vein

Pyloric canal

B. Anterior View

Gastrocolic ligament (cut edge)

Right gastro-omental vessels

Endothoracic fascia

Pleura

Esophagogastric junction (Z line)

Pylorus

Upper limb of phrenicoesophageal ligament

E

Cardial orifice Diaphragm Gastric canal Duodenum

CO Pyloric canal

Pyloric orifice

Peritoneum Lower limb of phrenicoesophageal ligament

Z line

Pyloric sphincter (pylorus)

C. Anterior View, Internal Surface

Rugae Pyloric antrum

STOMACH A. Parts. B. External surface. C. Internal surface (m ucous m em brane), anterior wall rem oved. Insets: Left side of page—pylorus, viewed from the duodenum . Right side of page—details of the esophagogastric

4.32 junction. The Z line is where the strati ed squam ous epithelium of the esophagus (white portion in photograph) changes to the sim ple colum nar epithelium of the stom ach (dark portion).

Ab d o m e n

324

STOMACH

Left gastric artery Celiac trunk Common hepatic artery Right and left branches

Esophageal branch

Posterior gastric artery Splenic artery Short gastric arteries

Cystic artery Hepatic artery proper

Splenic branches

Right gastric artery Gastroduodenal artery Supraduodenal artery

Left gastro-omental artery

Abdominal aorta Right gastro-omental artery Superior pancreaticoduodenal artery

A. Anterior View Esophageal branch Left gastric artery Splenic artery Common hepatic artery

Splenic artery

Short gastric arteries

Spleen Splenic branches

Posterior gastric artery

Celiac trunk

Hepatic artery proper Right gastric artery Gastroduodenal artery

Supraduodenal artery Superior pancreaticoduodenal artery Left gastro-omental (gastro-epiploic) artery

Right gastro-omental artery

B. Anterior View

4.33

CELIAC ARTERY

A. Branches of celiac trunk. The celiac trunk is a branch of the abdom inal aorta, arising im m ediately inferior to the aortic hiatus of the diaphragm (T12 vertebral level). The vessel is usually 1 to 2 cm long and divides into the left gastric, com m on hepatic, and splenic arteries. The celiac trunk supplies the liver, gallbladder, inferior

esophagus, stom ach, pancreas, spleen, and duodenum . B. Arteries of stom ach and spleen. The serous and m uscular coats are rem oved from two areas of the stom ach, revealing anastom otic networks in the subm ucous coat.

STOMACH Five main sites where esophagus is constricted:

Ab d o m e n

325 Fundus

1. Junction of pharynx and esophagus (in neck)

Lesser curvature Peristaltic wave (arrows)

2. Aortic arch

Greater curvature

Duodenal cap

Angular incisure

Pylorus Pyloric antrum

3. Left main bronchus (at tracheal bifurcation)

Gastric folds (rugae)

Duodenum

C 4. Left atrium Peristaltic wave (arrows) Duodenal cap Pylorus Pyloric antrum Duodenum

5. Esophageal hiatus

A. Lateral View

D Anterior Views (B–D)

Fundus of stomach Peristaltic wave Gallbladder Duodenal cap Pylorus Pyloric antrum Jejunum

B

Gastric folds (rugae) Greater curvature

RADIOGRAPHS OF ESOPHAGUS, STOMACH, DUODENUM (BARIUM SWALLOW)

4.34

A. Five sites of normal esophageal constriction. B. Stomach, small intestine, and gallbladder. Note additional contrast medium in gallbladder. C. Stomach and duodenum. D. Pyloric antrum and duodenal cap. Blockag e of esop h ag us. The impressions produced in the esophagus by adjacent structures are of clinical interest because of the slower passage of substances at these sites. The impressions indicate where swallowed foreign objects are most likely to lodge and where a stricture may develop, for example, after the accidental drinking of a caustic liquid, such as lye. A hiatal (hiatus) hernia is a protrusion of a part of the stomach into the mediastinum through the esophageal hiatus of the diaphragm. The hernias occur most often in people after middle age, possibly because of weakening of the muscular part of the diaphragm and widening of the esophageal hiatus.

Ab d o m e n

326

PANCREAS, DUODENUM, AND SPLEEN Gastric area

Short gastric vessels Left gastro-omental vessels

Transmitted by gastrosplenic ligament

Posterior end (medial end) S LS

RS

Diaphragm RK

Hilum of spleen P

LK

D

Splenorenal ligament containing splenic vessels and tail of pancreas*

Hilum of spleen

*

Renal area

Colic area

A. Anterior View Key

Key

D

Duodenum

RK Right kidney

Anterior border

LK

Left kidney

RS

Right suprarenal gland

Inferior border

LS

Left suprarenal gland

S

Stomach

P

Pancreas

4.35

B. Inferomedial View

Superior border

SPLEEN

A. The surface anatom y of the spleen. The spleen lies super cially in the left upper abdom inal quadrant between the 9th and 11th ribs. B. Note the im pressions (colic, renal, and gastric areas) m ade by

structures in contact with the spleen’s visceral surface. Its superior border is notched.

Left gastric artery

Left branch of hepatic artery

T10

Right branch of hepatic artery

Splenic artery

Right gastric artery

Left gastroomental artery

Hepatic artery proper

Celiac trunk

Common hepatic artery

Gastroduodenal artery

Anterior View

4.36

CELIAC ARTERIOGRAM

Catheter

Right gastro-omental artery

Ab d o m e n

PANCREAS, DUODENUM, AND SPLEEN 1–4 Parts of duodenum

327

Left suprarenal gland

A Uncinate process B Head of pancreas C Neck D Body E Tail

Left kidney

Left gastric artery

Hepatic artery proper

Diaphragm

Hepatic portal vein

Spleen

Splenic artery

Celiac trunk

Bile duct Right suprarenal gland Right kidney E Gallbladder Gastroduodenal artery

1

Accessory pancreatic duct

D

Minor duodenal papilla Major duodenal papilla

C

2

Vertebral levels

A

B

4

Main pancreatic duct Superior mesenteric vein and artery

3

Duodenum Ascending colon Psoas Inferior vena cava

Descending colon

Left ureter

Right ureter Abdominal aorta Anterior View

Inferior mesenteric vein

Suspensory muscle

Inferior mesenteric artery

4.37

PARTS AND RELATIONSHIPS OF PANCREAS AND DUODENUM Pancreas and duodenum in situ.

TABLE 4.5

PARTS AND RELATIONSHIPS OF DUODENUM

Pa rt of Duodenum

Anterior

Posterior

Superior (1st) part

Peritoneum Gallbladder Quadrate lobe of liver

Bile duct Gastroduodenal artery Hepatic portal vein IVC

Descending (2nd) part

Transverse colon Transverse mesocolon Coils of small intestine

Hilum of right kidney Renal vessels Ureter Psoas major

Inferior (horizontal or 3rd) part

Superior mesenteric artery Superior mesenteric vein Coils of small intestine

Right psoas major IVC Aorta Right ureter

Ascending (4th) part

Beginning of root of mesentery Coils of jejunum

Left psoas major Left margin of aorta

Media l

Superior

Inferior

Vertebra l Level

Neck of gallbladder

Neck of pancreas

Anterolateral to L1 vertebra

Head of pancreas Pancreatic duct Bile duct

Superior mesenteric artery and vein

Right of L2–L3 vertebrae

Head and uncinate process of pancreas Superior mesenteric artery and vein

Anterior to L3 vertebra

Body of pancreas

Left of L3 vertebra

328

4.38

Ab d o m e n

PANCREAS, DUODENUM, AND SPLEEN

VASCULAR RELATIONSHIPS OF PANCREAS AND DUODENUM

A. Anterior relationships. The gastroduodenal artery descends anterior to the neck of the pancreas. B. Posterior relationships. The splenic artery and vein course on the p osterior aspect of the p ancreatic tail, which usually extends to the spleen. The pancreas “loops” around the right side of the superior m esenteric vessels so that its neck is anterior, its head is to the right, and its uncinate process is posterior to the vessels. The splenic and sup erior m esenteric veins unite posterior to the neck to form the hep atic portal vein. The b ile duct descends in a ssure (op ened up) in the posterior p art of the head of the pancreas. Most in am m atory erosions of the duodenal wall, d uo d e n al (p e p t ic) ulce rs, are in the p osterior wall of the superior (1st) part of the duodenum within 3 cm of the pylorus.

PANCREAS, DUODENUM, AND SPLEEN

Ab d o m e n

329

Left gastric artery Stomach (reflected superiorly) Celiac trunk Right gastric artery Hepatic artery proper Short gastric arteries Common hepatic artery

Posterior gastric artery Left gastro-omental (epiploic) artery

Gastroduodenal artery

Spleen Right gastro-omental (-epiploic) artery

Splenic branches

Anterior superior pancreaticoduodenal artery

Tail of pancreas

Duodenum Splenic artery Anterior pancreaticoduodenal arch

1st jejunal artery

Superior mesenteric artery

Duodenojejunal junction

Middle colic artery Vasa recta duodeni

A. Anterior View, with Stomach

Jejunal arteries

Reflected Superiorly

Left gastric artery Celiac trunk Common hepatic artery

Greater pancreatic artery

Splenic artery

BLOOD SUPPLY TO THE PANCREAS, DUODENUM, AND SPLEEN

Gastroduodenal artery Posterior superior pancreaticoduodenal artery

Artery to tail of pancreas Inferior pancreatic artery

Anterior superior pancreaticoduodenal artery

Dorsal pancreatic artery

Anterior pancreaticoduodenal arch

1st jejunal artery

Posterior pancreaticoduodenal arch

Superior mesenteric artery

Anterior inferior pancreaticoduodenal artery

B. Anterior View

Posterior inferior pancreaticoduodenal artery

Common stem of posterior inferior and anterior inferior pancreaticoduodenal arteries

4.39

A. Celiac trunk and superior m esenteric artery. B. Pancreatic and p ancreaticoduodenal arteries. • The anterior superior p ancreaticoduodenal artery from the gastroduodenal artery and the anterior inferior pancreaticoduodenal artery of the superior m esenteric artery form the anterior pancreaticoduodenal arch anterior to the head of the pancreas. The posterior superior and posterior inferior branches of the sam e two arteries form the posterior pancreaticoduodenal arch posterior to the pancreas. The anterior and posterior inferior arteries often arise from a com m on stem . • Arteries supp lying the p ancreas are d erived from the com m on hepatic artery, gastroduodenal artery, pancreaticoduodenal arches, splenic artery, and sup erior m esenteric artery.

Ab d o m e n

330

INTESTINES

Gastrocolic part of greater omentum (reflected)

Transverse colon

Omental appendices

Right colic flexure

B Descending colon Parietal peritoneum

Taeniae coli

C Ascending colon Haustra

D

Sigmoid colon Cecum Appendix

Urinary bladder

Inferior epigastric artery

Rectus abdominis

A. Anterior View

B. Proximal Jejunum

4.40

C. Proximal Ileum

D.

Distal Ileum

INTESTINES IN SITU, INTERIOR OF SMALL INTESTINE

A. Intestines in situ, greater om entum re ected. The ileum is reected to exp ose the ap pendix. The ap pendix usually lies posterior to the cecum (retrocecal) or, as in this case, projects over the pelvic brim . The features of the large intestines are the taeniae coli, haustra, and om ental appendices. B. Proxim al jejunum . The

circular folds are tall, closely packed, and com m only branched. C. Proxim al ileum . The circular folds are low and becom ing sp arse. The caliber of the gut is reduced, and the wall is thinner. D. Distal ileum . Circular folds are absent, and solitary lym ph nodules stud the wall.

INTESTINES

Ab d o m e n

331

Gastrocolic part of greater omentum

B Transverse colon Jejunum Mesentery of small intestine

Descending colon

Duodenojejunal junction Aorta

Ileum Sigmoid colon

Sigmoid mesocolon

A. Anterior View

SIGMOID MESOCOLON AND MESENTERY OF SMALL INTESTINE, INTERIOR OF TRANSVERSE COLON Taeniae coli Semilunar fold

Haustra

B. Transverse Colon

4.41

A. Sigm oid m esocolon and m esentery of the sm all intestine. • The d uodenojejunal junction is situated to the left of the m edian plane. • The m esentery of the sm all intestine fans out extensively from its short root to accom m odate the length of jejunum and ileum ( 6 m ). • The d escending colon is the narrowest part of the large intestine and is retrop eritoneal. The sigm oid colon has a m esentery, the sigm oid m esocolon; the sigm oid colon is continuous with the rectum at the point at which the sig m oid m esocolon ends. B. Transverse colon. The sem ilunar folds and taeniae coli form prom inent features on the sm ooth-surfaced wall.

Ab d o m e n

332

INTESTINES

T

D

C

A

B Postero-anterior Radiographs Key A Ascending colon C Cecum D Descending colon

G Sigmoid colon H Hepatic flexure R Rectum

S Splenic flexure T Transverse colon U Haustra

Transverse colon

Flexible colonoscope Ascending colon

4.42

BARIUM ENEMA AND COLONOSCOPY OF COLON

A. Single-contrast study. A barium enem a has lled the colon. B. Double-contrast study. Barium can be seen coating the walls of the colon, which is distended with air, p roviding a vivid view of the m ucosal relief and haustra. C. The interior of the colon can be observed with an elongated endoscope, usually a beroptic exible colonoscop e. The endoscope is a tube that inserts into the colon through the anus and rectum . D. Diverticulosis of the colon can be photographed through a colonoscop e. E. Diverticulosis is a disorder in which m ultip le false diverticula (external evaginations or outpocketings of the m ucosa of the colon) develop along the intestine. It p rim arily affects m iddleaged and elderly people. Diverticulosis is com m only (60%) found in the sigm oid colon. Diverticula are subject to infection and rupture, leading to d ive rt iculit is, and they can distort and erode the nutrient arteries, leading to hem orrhage.

Descending colon

Sigmoid colon Rectum

Presence of diverticula

C. Anterior View

D. Colonoscopic View

E. Diverticulosis

INTESTINES

Ab d o m e n

333

Ascending branch Ileocolic artery Taeniae coli Ileal branch Anterior and posterior cecal branches Superior ileocecal recess Vascular fold of cecum

64% 0.5%

Ileum Inferior ileocecal recess Inferior ileocecal fold

Ileum

Meso-appendix

1%

Cecum

Appendix

Appendicular artery

A. Anterior View

Appendix

B. Anterior View

2%

32%

Haustrum (sacculation) of colon

Ileocecal orifice Ileum

Ileal diverticulum

Orifice of appendix

Appendix

C. Anterior View

ILEOCECAL REGION AND APPENDIX A. Blood supply. The appendicular artery is located in the free edge of the m eso-ap pendix. The inferior ileocecal fold is bloodless, whereas the superior ileocecal fold is called the vascular fold of the cecum . B. The ap proxim ate incidence of various positions of the appendix. C. Interior of a dried cecum and ileal diverticulum (of Meckel). This cecum was lled with air until dry, op ened , and

4.43 varnished. Ileal diverticulum is a congenital anom aly that occurs in 1% to 2% of persons. It is a pouchlike rem nant (3 to 6 cm long) of the proxim al p art of the yolk stalk, typically within 50 cm of the ileocecal junction. It som etim es becom es in am ed and produces pain that m ay m im ic that produced by appendicitis.

Ab d o m e n

334

INTESTINES

Jejunum

Transverse colon Marginal artery Omental appendix Taeniae coli

Translucent area

Vasa recta Arcades

Haustra

Middle colic artery

Jejunum

Vasa recta

Right colic artery

Superior mesenteric artery Ascending colon Ileocolic artery

Ileal branches Ileum

Cecum Vasa recta Fat

Appendicular artery Appendix Anterior View

4.44

Arcades

Ileum

SUPERIOR MESENTERIC ARTERY AND ARTERIAL ARCADES

The peritoneum is partially stripped off. • The sup erior m esenteric artery ends by anastom osing with one of its own branches, the ileal branch of the ileocolic artery. • On the inset drawings of jejunum and ileum , com p are the diam eter, thickness of wall, num ber of arterial arcades, long or short vasa recta, presence of translucent (fat-free) areas at the m esenteric border, and fat encroaching on the wall of the gut between the jejunum and ileum .

• Acut e in am m at io n o f t h e ap p e n d ix is a com m on cause of an acute abdom en (severe abdom inal pain arising suddenly). The pain of appendicitis usually com m ences as a vague pain in the peri-um bilical region because afferent pain bers enter the spinal cord at the T10 level. Later, severe p ain in the right lower quadrant results from irritation of the parietal peritoneum lining the posterior abdom inal wall.

INTESTINES

Ab d o m e n

335

Gas in transverse colon Superior mesenteric artery Marginal artery

Middle colic artery

Jejunal arteries Ileal arteries Right colic artery Gas in ascending colon Ileocolic artery Catheter

Ileocecal junction

A Anteroposterior Arteriograms Vasa recta

Superior mesenteric artery

Arterial arcades

Jejunal arteries

B

SUPERIOR MESENTERIC ARTERIOGRAMS A. Branches of superior m esenteric artery. Consult Figure 4.44 to identify the branches. B. Enlargem ent to show the jejunal arteries, arterial arcad es, and vasa recta. • The branches of the superior m esenteric artery include, from its left side, 12 or m ore jejunal and ileal arteries that anastom ose to form arcades from which vasa recta pass to the sm all intestine and, from its right side, the m iddle colic, ileocolic, and com m only (but not here) an independent right colic artery that anastom ose to form a m arginal artery that parallels the m esenteric border at the colon and from which vasa recta pass to the large intestine.

4.45 • Occlusio n o f t h e vasa re ct a by em boli results in ischem ia of the part of the intestine concerned. If the ischem ia is severe, necrosis of the involved segm ent results and ile us (obstruction of the intestine) of the paralytic typ e occurs. Ileus is accom panied by a severe colicky pain, along with abdom inal distension, vom iting, and often fever and dehydration. If the condition is diagnosed early (e.g., using a superior m esenteric arteriogram ), the obstructed part of the vessel m ay be cleared surgically.

336

Ab d o m e n

INTESTINES

Transverse colon

Marginal artery

Site of anastomosis of SMAand IMA

Middle colic artery

Superior mesenteric artery (SMA)

Duodenum

Inferior mesenteric artery (IMA)

Left colic artery

Abdominal aorta

Descending colon Marginal artery

Sigmoid arteries Right common iliac artery Left common iliac artery Superior rectal artery "Critical point" of superior rectal artery, anastomosis poor or absent

Sigmoid colon Anterior View

4.46

INFERIOR MESENTERIC ARTERY

The m esentery of the sm all intestine has been cut at its root. • The inferior m esenteric artery arises posterior to the ascending part of the duodenum , about 4 cm superior to the bifurcation of the aorta; on crossing the left com m on iliac artery, it becom es the superior rectal artery. • The branches of the inferior m esenteric artery include the left colic artery and several sig m oid arteries; the inferior two sigm oid arteries branch from the sup erior rectal artery.

• The point at which the last sigm oidal artery branches from the sup erior rectal artery is known as the “critical point” of the superior rectal artery; distal to this point, there are poor or no anastom otic connections b etween the superior rectal artery and the m arginal artery.

INTESTINES

Ab d o m e n

337

Ascending branch of left colic artery

Inferior mesenteric artery

Right renal pelvis

Marginal artery Right ureter

Left colic artery

Descending branch of left colic artery Gas in ascending colon

Descending colon

Catheter

Sigmoid arteries

Superior rectal artery

Gonadal radiation shield

Postero-anterior Arteriogram

INFERIOR MESENTERIC ARTERIOGRAM • The left colic artery courses to the left toward the descending colon and sp lits into ascending and descending branches. • The sigm oid arteries, two to four in num ber, sup ply the sigm oid colon.

4.47 • The sup erior rectal artery, which is the continuation of the inferior m esenteric artery, supplies the rectum ; the superior rectal anastom oses are form ed by branches of the m iddle and inferior rectal arteries (from the internal iliac artery).

338

Ab d o m e n

INTESTINES

Transverse colon

Gastrocolic ligament (part of greater omentum)

Duodenojejunal junction Jejunum

Middle colic artery in transverse mesocolon

Root of mesentery of small intestine (cut)

Right colic flexure

Descending colon

Duodenum

Abdominal aorta Inferior mesenteric artery

Ascending colon Psoas (deep to peritoneum)

Appendices epiploicae Taenia coli

Sigmoid colon

Cecum

Sigmoid mesocolon

Inferior epigastric artery Ileum Obliterated umbilical artery Anterior View

4.48

PERITONEUM OF POSTERIOR ABDOMINAL CAVITY

The gastrocolic ligam ent is retracted superiorly, along with the transverse colon and transverse m esocolon. The appendix had been surgically rem oved. This dissection is continued in Figure 4.49. • The root of the m esentery of the sm all intestine, app roxim ately 15 to 20 cm in length, extends between the duodenojejunal junction and ileocecal junction. • The larg e intestine form s 3½ sid es of a sq uare, “fram ing ” the jejunum and ileum . On the rig ht are the cecum and ascend ing colon, sup erior is the transverse colon, on the left

is the d escend ing and sig m oid colon, and inferiorly is the sig m oid colon. • Ch ro n ic in am m at io n o f t h e co lo n (ulce rat ive co lit is, Cro h n d ise ase ) is characterized by severe in am m ation and ulceration of the colon and rectum . In som e patients, a colectom y is perform ed, during which the term inal ileum and colon as well as the rectum and anal canal are rem oved. An ileostom y is then constructed to establish an arti cial cutaneous opening between the ileum and the skin of the anterolateral abdom inal wall.

INTESTINES

Ab d o m e n

339

Transverse colon Transverse mesocolon

Middle colic artery

Jejunum

Anterior superior pancreaticoduodenal artery

Inferior part of duodenum

Pancreas Kidney

Descending part of duodenum (covered with peritoneum)

Psoas

Jejunal and ileal arteries Descending colon

Superior mesenteric artery and vein

Left colic artery

Ileocolic artery

Inferior mesenteric artery and vein

Right colic artery

Testicular vein and artery

Paracolic lymph node Ureter Ascending colon Anterior longitudinal ligament covering body of L5 vertebra Superior hypogastric plexus on left common iliac vein

5th lumbar (L5/S1) intervertebral disc (sacral promontory)

Sigmoid arteries

Cecum

Sigmoid mesocolon Ileum Anterior View Appendices epiploicae

Sigmoid colon

POSTERIOR ABDOMINAL CAVITY WITH PERITONEUM REMOVED The jejunal and ileal branches (cut) pass from the left side of the sup erior m esenteric artery. The right colic artery here is a b ranch of the ileocolic artery. This is the sam e specim en as in Fig ure 4.48. • The duodenum is larger in diam eter before crossing the superior m esenteric vessels and narrow afterward. • On the right side, there are lym ph nod es on the colon, p aracolic nodes beside the colon, and nodes along the ileocolic artery, which drain into nodes anterior to the p ancreas.

4.49

• The intestines and intestinal vessels lie on a resectable plane (rem nant of the em bryological dorsal m esentery) anterior to that of the testicular vessels; these, in turn, lie anterior to the plane of the kidney, its vessels, and the ureter. • The superior hyp ogastric plexus lie inferior to the bifurcation of the aorta and anterior to the left com m on iliac vein, the body of the 5th lum bar vertebra, and the 5th intervertebral disc.

340

Ab d o m e n

LIVER AND GALLBLADDER

Coronary ligament

Right lobe

Left triangular ligament

Left lobe

Falciform ligament

Round ligament of liver (ligamentum teres hepatis)

Gallbladder

A. Anterior View

Bare area Ligament of inferior vena cava Right triangular ligament

Inferior vena cava

Caudate lobe

Left triangular ligament

Openings of right and left hepatic veins

Coronary ligament Right lobe

Bare area Left lobe

Coronary ligament Falciform ligament

B. Superior View

4.50

DIAPHRAGMATIC (ANTERIOR AND SUPERIOR) SURFACE OF LIVER

A. The falciform ligam ent has been severed close to its attachm ent to the diaphragm and anterior abdom inal wall and dem arcates the right and left lobes of the liver. The round ligam ent of the liver (ligam entum teres) lies within the free edge of the falciform ligam ent.

B. The two layers of p eritoneum that form the falciform ligam ent separate over the sup erior aspect (surrounding the b are area) of the liver to form the superior layer of the coronary ligam ent and the right and left triangular ligam ents.

LIVER AND GALLBLADDER

Ab d o m e n

341

Left triangular ligament Lesser omentum

Diaphragmatic area Bare area Inferior vena cava

Esophageal area

Line approximating separation between diaphragmatic and visceral surfaces Suprarenal area

Left lobe Gastric area Caudate lobe

Coronary ligament

Hepatic artery

Renal area

Bile duct

Caudate process

Porta hepatis

Hepatic portal vein

Pyloric area

Right lobe

Quadrate lobe

Duodenal area Gallbladder

Falciform ligament Round ligament of liver

A. Postero-inferior View Colic area

Caudate lobe

Anterior layer of coronary ligament

Left lobe

Bare area of liver

Ligamentum venosum (ductus venosus)

Liver

Posterior layer of coronary ligament Posterior abdominal muscles

Visceral

Caudate process

Right lobe

Round ligament (umbilical vein) Right kidney

Subphrenic recess Inferior border of liver

Surfaces of the Liver: Diaphragmatic

Inferior vena cava (in groove for vena cava)

Lung

Diaphragm

Hepatorenal recess

Subhepatic space

B. Sagittal Section

VISCERAL (POSTERO-INFERIOR) SURFACE OF LIVER A. Isolated specim en dem onstrating lobes, and im pressions of adjacent viscera. B. Hepatic surfaces and peritoneal recesses. C. Round ligam ent of liver and ligam entum venosum . The round ligam ent of liver includes the obliterated rem ains of the um bilical vein that carried well-oxygenated blood from the placenta to the fetus. The ligam entum venosum is the brous rem nant of the fetal ductus venosus that shunted blood from the um bilical vein to the inferior

Hepatic Portal triad: portal vein enters liver at Hepatic artery porta hepatis Bile passages

Quadrate lobe

Gallbladder (in fossa for gallbladder)

C. Postero-inferior View

4.51 vena cava by passing the liver. Hepatic tissue m ay be obtained for diagnostic purposes by live r b io p sy. The needle puncture is com m only m ade through the right 10th intercostal space in the m idaxillary line. Before the physician takes the biop sy, the person is asked to hold his or her breath in full expiration to m inim ize the costodiaphragm atic recess and to lessen the possibility of dam aging the lung and contam inating the pleural cavity.

342

Ab d o m e n

LIVER AND GALLBLADDER

Stomach Right lobe of liver Falciform ligament

Round ligament of liver Gallbladder Transverse mesocolon (root) Site of ascending colon Mesentery of small intestine (root) Anterior View

Site of descending colon

A

Left triangular ligament

Falciform ligament

Falciform ligament

Coronary ligament

Bare area

Inferior vena cava

Left triangular ligament

Superior recess

Bare area

Caudate lobe Lesser omentum Caudate process

Posterior View

Right triangular ligament Hepatorenal recess Anterior View

B

4.52

LIVER AND ITS POSTERIOR RELATIONS, SCHEMATIC ILLUSTRATION

A. Liver in situ. The jejunum , ileum , and the ascending, transverse, and d escending colons have been rem oved. B. The liver is drawn schem atically on a p age in a book, so that as the p age is turned (arrow in A), the liver is re ected to the right to reveal its p osterior

surface, and on the facing p age, the posterior relations that com pose the bed of the liver are viewed. The arrow ( B) traverses the om ental (ep iploic) foram en to enter the om ental bursa and its sup erior recess (arrowhead).

Ab d o m e n

LIVER AND GALLBLADDER

343

Inferior vena cava

Right Intermediate Hepatic veins (middle) Left

Hepatic artery Hepatic portal vein Bile duct

Portal triad

Removed portion of liver

Round ligament of liver

Plane of section

A B

A. Superior View

Liver tissue

Hepatic portal vein (portal triad)

Intermediate (middle) hepatic vein Left hepatic vein Right hepatic vein Diaphragm

B. US, Inferior View

HEPATIC VEINS A. Approxim ately horizontal section of liver with the posterior asp ect at the top of p age. Note the m ultip le p erivascular brous cap sules sectioned throughout the cut surface, each containing a portal triad (the hepatic portal vein, hepatic artery, bile ductules) plus lym ph vessels. Interdigitating with these are branches of the

4.53 three m ain hepatic veins (right, interm ediate, and left), which, unaccom panied and lacking capsules, converge on the inferior vena cava. B. Ultrasound scan. The transducer was placed under the costal m argin and directed posteriorly, producing an inverted im age ( A) .

Ab d o m e n

344

LIVER AND GALLBLADDER Inferior vena cava Left hepatic vein Intermediate (middle) hepatic vein

Right hepatic vein

II

VII 3°

VIII

Key



T

M = Main portal fissure R = Right portal fissure T = Transverse hepatic plane U = Umbilical fissure 2° = Secondary branches of portal triad structures 3° = Tertiary branches of portal triad structures

I 3°

IV 2°





III



U

VI

Right and left (1°) branches of hepatic artery Portal vein Hepatic artery Portal triad Bile duct

M

V

Gallbladder

A. Anterior View

R

Right (part of) liver

Left (part of) liver Right medial division

Right lateral division

VII

VIII

Left medial division

Posterior (part of) liver (caudate lobe)

Left lateral division II

IV

II

VII I

III III VI

IV

V

Left lobe Right lobe

B Right posterior medial segment

V

VI

Division between right and left (parts of) liver (right sagittal fissure)

C Left medial segment

Left posterior lateral segment

Left posterior lateral segment

Posterior (caudate) segment

Right posterior lateral segment

Right posterior lateral segment Left anterior lateral segment

Right anterior lateral segment

D

Left anterior lateral segment Right anterior medial segment Anterior Views (B, D)

4.54

Right anterior lateral segment

HEPATIC SEGMENTATION

Left medial segment

E

Right anterior medial segment

Postero-inferior Views (C, E)

Ab d o m e n

LIVER AND GALLBLADDER

4.54

HEPATIC SEGMENTATION (continued ) Each segm ent is sup plied by a secondary or tertiary branch of the hepatic artery, bile duct, and portal vein. The hepatic veins interdigitate between the portal triads and are intersegm ental in that they drain adjacent segm ents. Since the right and left hepatic

TABLE 4.6

a

345

arteries and ducts and branches of the right and left portal veins do not com m unicate, it is possible to perform h e p at ic lo b e ct o m ie s (rem oval of the right or left p art of the liver) and se g m e n t e ct om ie s. Each segm ent can be identi ed num erically or by nam e (Table 4.6).

SCHEMA OF TERMINOLOGY FOR SUBDIVISIONS OF LIVER

Ana tomica l Term

Right Lobe

Left Lobe

Ca uda te Lobe

Functional/surgical term a

Right (part of) liver [Right portal lobe b]

Left (part of) liver [Left portal lobe c ]

Posterior (part of) liver

Right lateral division

Right medial division

Left medial division

Left lateral division

Posterior lateral segment Se g m e nt VII [Posterior superior area]

Posterior medial segment Se g m e nt VIII [Anterior superior area]

[Medial superior area]

Lateral segment Se g m e nt II [Lateral superior area]

Right anterior lateral segment Se g m e nt VI [Posterior inferior area]

Anterior medial segment Se g m e nt V [Anterior inferior area]

Left medial segment Se g m e nt IV [Medial inferior area quadrate lobe]

[Right caudate lobe b]

Left anterior lateral segment Se g m e nt III [Lateral inferior area]

[Left caudate lobe c ]

Posterior segment Se g m e nt I

The labels in the table and gure above re ect the Terminologia Anatomica: International Anatomical Terminology. Previous terminology is in brackets. Under the schema of the previous terminology, the caudate lobe was divided into right and left halves, and bthe right half of the caudate lobe was considered a subdivision of the right portal lobe; cthe left half of the caudate lobe was considered a subdivision of the left portal lobe.

b,c

Hepatic portal vein Interlobular Hepatic artery portal triad Biliary duct

Deep lymphatic duct receiving lymph from perisinusoidal space

Kupffer cell (sinusoidal macrophage) Bile canaliculi Bile flowing from hepatocytes into bile canaliculi, to interlobular biliary ducts, and then to the bile duct in the extrahepatic portal triad

Blood flowing in sinusoids from interlobular (hepatic) artery and (portal) vein

Central vein

Perisinusoidal spaces (of Disse)

Liver lobules

Interlobular portal triads Peribiliary arterial plexus

Hepatocytes (produce bile and detoxify blood)

FLOW OF BLOOD AND BILE IN THE LIVER This sm all part of a liver lobule shows the com ponents of the interlobular portal triad and the p ositioning of the sinusoids and bile canaliculi (right). The cut surface of the liver shows the hexagonal pattern of the lobules. • With the exception of lipids, every substance absorb ed by the alim entary tract is received rst by the liver via the hepatic portal

Central vein (transports clean blood to hepatic vein)

Central vein Sinusoids

Hepatocytes

4.55 vein. In addition to its m any m etabolic activities, the liver stores glycogen and secretes bile. • There is progressive destruction of hepatocytes in cirrh o sis o f t h e live r and replacem ent of them by brous tissue. This tissue surrounds the intrahep atic blood vessels and biliary ducts, m aking the liver rm and im peding circulation of blood through it.

346

Ab d o m e n

LIVER AND GALLBLADDER

Falciform ligament

Liver

Caudate lobe Left (hepatic) branch Round ligament of liver

Common hepatic duct Hepatic portal vein Right (hepatic) branch

Gallbladder

Bile duct Peritoneum

Cystic duct

Duodenum (retracted anteriorly) Peritoneum (cut edge) Areolar membrane (fusion fascia)

Hepatorenal recess

Bare area for colon Perirenal fat Pancreas Right kidney

Ureter

Abdominal aorta Testicular vein and artery

Inferior vena cava

A. Anterior View

4.56

EXPOSURE OF THE PORTAL TRIAD IN HEPATODUODENAL LIGAMENT

A. The hepatoduodenal ligam ent (hepatic pedicle) includes the portal triad consisting of the hepatic portal vein (posteriorly), the hepatic artery proper (ascending from the left), and the bile passages (descending to the right). Here, the hepatic artery p rop er is replaced by a left hepatic branch, arising directly from the com m on hepatic artery, and a right hepatic branch, arising from the sup erior m esenteric artery (a com m on variation). A rod traverses

the om ental (epiploic) foram en. The lesser om entum and transverse colon are rem oved, and the peritoneum is cut along the right border of the duodenum ; this part of the duodenum is retracted anteriorly. The space opened up reveals two sm ooth areolar m em branes (fusion fascia) norm ally applied to each other that are vestig es of the em bryonic peritoneum originally covering these surfaces.

LIVER AND GALLBLADDER

Ab d o m e n

347

Gallbladder

Cystic duct

Left (hepatic) branch Common hepatic duct

Right lobe of liver

Common hepatic artery Rod in omental (epiploic) foramen

Gastroduodenal artery Bile duct

Aberrant right hepatic artery

Posterior superior pancreaticoduodenal artery

Hepatic portal vein Pancreaticoduodenal lymph node

Head of pancreas, posterior surface

Right renal vein and artery

Posterior pancreaticoduodenal arch Posterior inferior pancreaticoduodenal artery

Right kidney Inferior vena cava

Superior mesenteric artery Duodenum

Extraperitoneal fascia

Parietal peritoneum Quadratus lumborum Psoas Testicular vein Testicular artery

Abdominal aorta Ureter

B. Anterior View

EXPOSURE OF THE PORTAL TRIAD IN HEPATODUODENAL LIGAMENT (continued ) B. Continuing the dissection, the second arily retrop eritoneal viscera (d uodenum and head of the p ancreas) are retracted anteriorly and to the left. The areolar m em brane (fusion fascia) covering the posterior aspect of the pancreas and duodenum is largely rem oved, and that covering the anterior aspect of the great vessels is partly rem oved.

4.56

A com m on m ethod for re d ucin g p o rt al h yp e rt e n sio n is to divert blood from the p ortal venous system to the system ic venous system by creating a com m unication between the portal vein and the inferior vena cava (IVC). This p o rt acaval an ast o m o sis or p o rt o syst e m ic sh un t m ay be created where these vessels lie close to each other posterior to the liver.

348

Ab d o m e n

LIVER AND GALLBLADDER

Round ligament of liver (obliterated umbilical vein)

Gallbladder Superficial branch

Cystic artery

Deep branch

Left hepatic duct

Cystic duct

Left branch

Right branch Common hepatic duct

Left hepatic branch

Ligamentum venosum (obliterated ductus venosus)

Right hepatic branch

A. Inferior View Hepatic artery proper

Inferior vena cava Hepatic portal vein

Bile duct

Hepatic artery and duct

Cystic veins

Right

Gallbladder

Fossa for gallbladder

Left

Cystohepatic triangle (common hepatic duct, cystic duct, inferior surface of liver), surgical site for locating cystic artery Common hepatic duct Hepatic artery

Cystic artery To liver

Abdominal aorta Celiac trunk Cystic duct Hepatic portal vein

To left portal vein Anterior cystic vein Posterior cystic vein Cystic duct

Common hepatic duct Right gastric vein

Hepatoduodenal ligament (cut edge) Duodenum

4.57

Stomach

Gastroduodenal artery Pancreas

Posterior superior pancreaticoduodenal vein Gallbladder Retracted

Hepatogastric ligament (cut edge)

Bile duct

Bile duct

B. Inferior View with

Splenic artery

C. Anterior View (Liver Removed)

GALLBLADDER AND STRUCTURES OF PORTA HEPATIS

A. Gallbladder, cystic artery, and extrahepatic bile ducts. The inferior border of the liver is elevated to dem onstrate its visceral surface (as in orientation gure). B. Venous drainage of the gallbladder and extrahepatic ducts. Most veins are tributaries of the hepatic portal vein, but som e drain directly to the liver. C. Portal triad within the hepatoduodenal ligam ent (free edge of lesser om entum ).

Gallst o n e s are concretions in the gallbladder or extrahepatic biliary ducts. The cystohepatic (hepatobiliary) triangle (Calot), between the com m on hepatic duct, cystic duct, and liver, is an im portant endoscopic landm ark for locating the cystic artery during ch o le cyst e ct o m y.

LIVER AND GALLBLADDER

Ab d o m e n

349

Quadrate lobe of liver

Fossa for gallbladder

Left hepatic duct Left branch of hepatic portal vein

Right hepatic duct Right branch of hepatic portal vein

Middle and left (hepatic) branches

Right hepatic branch Cystic artery

Hepatic portal vein Hepatic artery proper

Cystic duct

Common hepatic artery Left gastric vein

Bile duct

Gastroduodenal artery Pancreas Right gastric artery and vein

Deep branch of cystic artery Duodenum

A. Anterior View, Liver Reflected Superiorly

Accessory or replaced left hepatic artery may originate from left gastric artery

Left hepatic branch

Gastroduodenal artery

B. Anterior View

Left gastric artery Splenic artery Superior mesenteric artery Accessory or replaced right hepatic artery may originate from superior mesenteric artery

VESSELS IN PORTA HEPATIS A. Hepatic and cystic vessels. The liver is re ected superiorly. The gallbladder, freed from its bed or fossa, has rem ained nearly in its anatom ical p osition, p ulled slightly to the right. The deep branch of the cystic artery on the d eep , or attached, surface of the gallbladder anastom oses with branches of the super cial branch of the cystic artery and sends twigs into the bed of the gallbladder.

Left gastric artery

C. Anterior View

4.58 Veins (not all shown) accom p any m ost arteries. B. Aberrant (accessory or rep laced) right hepatic artery. C. Aberrant left hep atic artery. Awareness of the variations in arteries and bile duct form ation is im portant for surgeons when they ligate the cystic duct during ch ole cyst e ct o m y (rem oval of the gallbladder).

Ab d o m e n

350

BILIARY DUCTS

Gallbladder

Fundus

Right hepatic duct

Liver

Left hepatic duct

From right lobe

From quadrate lobe

Body

Right and left hepatic ducts

From left lobe

Mucous membrane Spiral fold (valve) in cystic duct

Cystic duct

From caudate lobe

Gallbladder

Common hepatic duct

Neck

Bile duct

Bile duct

Superior (1st) part

Main pancreatic duct

1

Accessory pancreatic duct

Descending part of duodenum Pylorus

C. Magnetic Resonance Cholangiopancreatography (MRCP)

Bile duct

Descending (2nd) part

Common hepatic duct

2 Main pancreatic duct

Minor duodenal papilla Hood

Ascending (4th) part

4 Hepatopancreatic ampulla

Major duodenal papilla Longitudinal fold

3

A. Anterior View Inferior (3rd) part

D. Internal View

E Accessory pancreatic duct Bile duct

4.59

Bile duct

1 D

Minor duodenal papilla

C

2 wall removed Major duodenal papilla

B

A

Main pancreatic duct

Superior mesenteric vein and artery

B. Anterior View

3

4

Key 1–4 Parts of duodenum Parts of pancreas: A Uncinate process (extends posterior to superior mesenteric vein) B Head D Body C Neck E Tail

BILE AND PANCREATIC DUCTS

A. and B. Extrahepatic bile p assages and p ancreatic ducts. C. Magnetic resonance cholangiopancreatography (MRCP) dem onstrating the bile and pancreatic ducts. The right and left hepatic ducts collect bile from the liver; the com m on hepatic duct unites with the cystic duct sup erior to the duodenum to form the bile duct, which descends posterior to the superior (1st) part of the duodenum . D. Interior of the descending (2nd) part of the duodenum . The bile duct joins the m ain pancreatic duct, form ing the hepatopancreatic am pulla, which opens on the m ajor duodenal p ap illa. This op ening is the narrowest part of the biliary passages and is the com m on site for im p act io n o f a g allst o n e . Gallstones m ay p roduce biliary colic (pain in the epigastric region). The accessory p ancreatic duct opens on the m inor duodenal papilla.

Ab d o m e n

BILIARY DUCTS

351

Accessory pancreatic duct Gallbladder Stomach Bile duct

Stomach Dorsal pancreas

Ventral pancreas

Dorsal pancreas Ventral pancreas

Bile duct Descending or 2nd part of duodenum Main pancreatic duct

Anterior Views

Anterior abdominal wall

Ventral pancreas

Ventral mesentery

Accessory pancreatic duct

Ventral mesentery Bile duct Dorsal pancreas

Main pancreatic duct Peritoneum

2nd part of duodenum

Duodenum

Dorsal mesentery Peritoneum

A

Inferior vena cava Aorta

Duodenum

D

B

C Transverse Sections

Accessory pancreatic duct

Accessory pancreatic duct

Accessory pancreatic duct

Primitive dorsal duct

Bile duct

Main pancreatic duct

E

Main pancreatic duct

Main pancreatic duct

F

G

Primitive ventral duct

Anterior Views

DEVELOPMENT AND VARIABILITY OF THE PANCREATIC DUCTS A–C. Anterior views (upper row) and transverse sections (middle row) of the stages in the developm ent of the pancreas. A. The sm all, prim itive ventral bud arises in com m on with the bile duct, and a larger, p rim itive dorsal bud arises independently from the duodenum . B. The 2nd , or descending, p art of the duodenum rotates on its long axis, which brings the ventral bud and bile duct posterior to the dorsal bud. C. A connecting segm ent unites the dorsal duct to the ventral duct, whereupon the duodenal end of

4.60

the dorsal duct atrophies, and the direction of ow within it is reversed. D–G. Com m on variations of the p ancreatic d uct. D. An accessory duct that has lost its connection with the duodenum . E. An accessory duct that is large enough to relieve an obstructed m ain duct. F. An accessory duct that could probably substitute for the m ain duct. G. A persisting p rim itive dorsal duct unconnected to the prim itive ventral duct.

Ab d o m e n

352

BILIARY DUCTS

Left hepatic duct Left hepatic duct Right hepatic duct Right hepatic duct Common hepatic duct

Common hepatic duct

Bile duct

Bile duct (common bile duct)

Pancreatic duct (partially filled)

Pancreatic duct T tube Duodenum

B.

A.

4.61

RADIOGRAPHS OF BILIARY PASSAGES

After a cholecystectom y (rem oval of the gallbladder), contrast m edium was injected with a T tube inserted into the bile passages.

Left hepatic branch

Left hepatic branch

Right hepatic branch

The biliary passages are visualized in the superior abdom en ( A) and are m ore localized in B.

Left hepatic branch

Right hepatic branch

Right hepatic branch

Right hepatic branch

Right hepatic branch

Hepatic portal vein

Hepatic portal vein

A. 24%

B. 64% Hepatic artery proper

Hepatic artery proper Right hepatic branch and duct

Cystic artery Cystic duct Bile duct Gastroduodenal artery

F. 75.5%

C. 12%

Left hepatic branch and duct

Common hepatic duct Cystohepatic triangle (of Calot) Hepatic artery proper Common hepatic artery

D. 91%

E. 9%

Hepatic arteries proper

Right hepatic branch and duct

Right hepatic branch and duct

Left hepatic branch and duct

Left hepatic branch and duct

6.2% 13.1% Cystic artery

Cystic artery

2.1% 2.6%

G. 0.5%

H. 24.0%

Anterior Views

4.62

VARIATIONS IN HEPATIC AND CYSTIC ARTERIES

In a study of 165 cadavers in Dr. Grant’s laboratory, ve patterns were observed. A. Right hepatic artery crossing anterior to bile passages, 24%. B. Right hepatic artery crossing posterior to bile passages, 64%. C. Aberrant artery arising from the superior mesenteric artery, 12%. The artery crossed anterior (D) to the portal vein in 91% and posterior

(E) in 9%. The cystic artery usually arises from the right hepatic artery in the angle between the common hepatic duct and cystic duct (see cystohepatic triangle, Fig. 4.57A), without crossing the common hepatic duct (F and G). However, when it arises on the left of the bile passages, it almost always crosses anterior to the passages (H).

Ab d o m e n

BILIARY DUCTS

Right hepatic duct

Liver

Left hepatic duct

Parts of gallbladder:

Common hepatic duct

Neck

Neck of gallbladder

Right and left hepatic ducts

Cystic duct

k

Body

N ec

Common hepatic duct

Body Fundus

353

Cystic duct

Fundus

A. Lateral View from Left

Bile duct

Bile duct Gallbladder

Duodenum

Duodenum

B. Sagittal Section

C. Lateral View from Left

4.63

GALLBLADDER AND EXTRAHEPATIC BILIARY DUCTS A. Gallbladd er dem onstrated by endoscopic retrograde cholangiography (ERCP). B. Relationships to sup erior part of duodenum . C. ERCP of bile p assages. En d o sco p ic re t ro g ra d e ch o la n g io g ra p h y (ERCP) is d on e b y rst p assin g a b erop tic end oscop e th roug h th e m outh ,

CHD

Common hepatic duct (CHD)

Cystic duct (CD)

esop h ag us, an d stom ach . Th en th e d uod en um is en tered , an d a can n ula is inserted in to th e m ajor d uod enal p ap illa an d ad van ced un d er uoroscop ic g uid an ce in to th e d uct of ch oice (b ile d uct or p an creatic d uct) for in jection of rad iog rap h ic con trast m ed ium .

CHD

CD

A. Low Union

B. High Union

CD

C. Swerving Course

G G

G

AHD CHD

AHD Inferior Views

CHD

D. Accessory Hepatic Duct (AHD)

E. Accessory Hepatic Duct (AHD)

VARIATIONS OF CYSTIC AND HEPATIC DUCTS AND GALLBLADDER The cystic duct usually lies on the right side of the com m on hepatic duct, joining it just above the superior ( rst) part of the duodenum , but this varies ( A–C) . Of 95 gallbladders and bile p assages studied in Dr. Grant’s laboratory, 7 had accessory ducts. Of these,

F. Folded Gallbladder (G)

G. Double Gallbladder (G)

4.64

four joined the com m on hepatic duct near the cystic duct ( D) , two joined the cystic duct ( E) , and one was an anastom osing duct connecting the cystic with the com m on hepatic duct. F. Folded gallbladder. G. Double gallbladder.

354

Ab d o m e n

PORTAL VENOUS SYSTEM

Inferior vena cava Left lobe of liver Right lobe of liver Esophageal branches of gastric veins Left gastric vein Stomach Cystic vein Short gastric vein

Gallbladder

Left branch Right branch

Spleen

Hepatic portal vein

Splenic vein Right gastric vein

Pancreatic vein Pancreas

Left and right gastro-omental veins

Pancreaticoduodenal veins Inferior mesenteric vein

Superior mesenteric vein Middle colic vein Descending colon Right colic veins Left colic veins

Ascending colon

Ileocolic vein Sigmoid veins

Jejunal and ileal veins Appendicular vein

Sigmoid colon

Cecum

Anterior View

Appendix Superior rectal veins Rectum

4.65

PORTAL VENOUS SYSTEM

• The hep atic p ortal vein drains venous blood from the g astrointestinal tract, spleen, pancreas, and gallbladder to the sinusoids of the liver; from here, the blood is conveyed to the system ic venous system by the hepatic veins that drain directly to the inferior vena cava. • The hep atic p ortal vein form s p osterior to the neck of the p ancreas b y the union of the superior m esenteric and splenic veins, with the inferior m esenteric vein joining at or near the angle of union. • The splenic vein drains blood from the inferior m esenteric, left gastro-om ental (epiploic), short gastric, and pancreatic veins.

• The right gastro-omental, pancreaticoduodenal, jejunal, ileal, right, and middle colic veins drain into the superior m esenteric vein. • The inferior m esenteric vein com m ences in the rectal plexus as the superior rectal vein and, after crossing the com m on iliac vessels, becom es the inferior m esenteric vein; branches include the sigm oid and left colic veins. • The hepatic p ortal vein divides into right and left branches at the porta hepatis. The left branch carries m ainly, but not exclusively, blood from the inferior m esenteric, gastric, and splenic veins, and the right branch carries blood m ainly from the superior m esenteric vein.

Ab d o m e n

PORTAL VENOUS SYSTEM

355

Azygos vein Esophageal vein Esophagus Inferior vena cava

(1)

Stomach Distended (dilated) veins (V)

Liver

Left gastric vein Splenic vein

Hepatic portal vein

Superior mesenteric vein Inferior mesenteric vein

Anterior View

Para-umbilical veins Colic vein

V Umbilicus Colon

(3)

V

(4)

Epigastric veins

V

View through esophagoscope

B. Esophageal Varices (V)

Retroperitoneal veins Superior rectal vein Middle rectal veins

Caput medusae

Inferior rectal vein

(2)

Anus

A. Anterior View

C. Anterior View

PORTACAVAL SYSTEM A. Portacaval system . In this diagram , portal tributaries (dark blue), and system ic tributaries and com m unicating veins (light blue). In p o rt al h yp e rt e n sio n (as in hep atic cirrhosis), the p ortal blood cannot pass freely through the liver, and the portocaval anastom oses becom e engorged, dilated, or even varicose; as a conseq uence, these veins m ay rup ture. The sites of the portocaval anastom osis shown are between (1) esophageal veins d raining into the azygos vein (system ic) and left g astric vein (p ortal), which when dilated are esophageal varices; (2) the inferior and m iddle rectal veins,

4.66 draining into the inferior vena cava (system ic) and the superior rectal vein continuing as the inferior m esenteric vein (portal) (hem orrhoids result if the vessels are dilated); (3) p araum bilical veins (p ortal) and sm all ep igastric veins of the anterior abdom inal wall (system ic), which when varicose form “cap ut m edusae” (so nam ed because of the resem blance of the radiating veins to the serpents on the head of Med usa, a character in Greek m ythology); and (4) twigs of colic veins (portal) anastom osing with system ic retroperitoneal veins. B. Esop hageal varices. C. Cap ut m edusae.

Ab d o m e n

356

POSTERIOR ABDOMINAL VISCERA

For caudate lobe of liver

For bare area of liver

Esophagus

IVC

Left gastric artery

Right suprarenal gland

For stomach Omental (epiploic) foramen (arrow)

For spleen Root of transverse mesocolon

For right lobe of liver cre Pa n

Duodenum

as

Left kidney For bare area of descending colon

Right kidney For bare area of ascending colon For small intestine

For small intestine

Root of mesentery of small intestine

A. Anterior View

Superior mesenteric artery and vein Ureter

Left Coronary ligament

Superior

Falciform ligament Left triangular ligament

Inferior

IVC SG Right triangular ligament

Superior recess of omental bursa (lesser sac)

Portal triad (Hepatoduodenal ligament)

Tail of pancreas

Splenorenal ligament

K

Right renal vein

Right ureter

Jejunum

Left suprarenal gland Left renal vein Duodenum

Right gonadal (ovarian/testicular) vein and artery

Left gonadal (ovarian/testicular) artery and vein

Intestinal vessels

C. Anterior View

B. Anterior View

4.67

POSTERIOR ABDOMINAL VISCERA AND THEIR ANTERIOR RELATIONS

A. Duodenum and pancreas in situ. Note the line of attachm ent of the root of the transverse m esocolon is to the body and tail of the pancreas. The viscera contacting speci c regions are indicated by the term “for.” The om ental (epiploic) foram en is traversed by

an arrow. B. After rem oval of duodenum and p ancreas. The three parts of the coronary ligam ent are attached to the diaphragm , except where the inferior vena cava (IVC), suprarenal g land (SG), and kidney (K) intervene. C. Pancreas and duodenum rem oved from A.

POSTERIOR ABDOMINAL VISCERA

Ab d o m e n

357

Celiac ganglion Celiac trunk

Posterior vagal trunk in esophageal hiatus Inferior phrenic artery and plexus

Hepatic veins

Spleen

Inferior phrenic artery

Costodiaphragmatic recess

Right suprarenal gland

10th rib Left suprarenal gland

Inferior vena cava

Right kidney

Diaphragm Abdominal aorta

Superior mesenteric artery

Left kidney

Descending colon

Subcostal artery and nerve Transversus abdominis

Sympathetic trunk External oblique

Quadratus lumborum

Internal oblique

Anterior ramus, L1 spinal nerve

Transversus abdominis

Left common iliac artery and vein Inferior mesenteric artery and vein

Iliacus Lateral cutaneous nerve of thigh Psoas

Testicular artery and vein Ureter

Femoral nerve

Sigmoid colon

Psoas fascia

Right internal iliac artery

Genitofemoral nerve External iliac artery and vein

Testicular artery and vein Ductus deferens

A. Anterior View

Celiac trunk Left renal vein and artery Superior mesenteric artery 3rd part of duodenum Small intestine Abdominal aorta B. Lateral View (from Left)

VISCERA AND VESSELS OF POSTERIOR ABDOMINAL WALL

4.68

A. Great vessels, kidneys, and suprarenal glands. B. Relationships of left renal vein and inferior (third) part of duodenum to aorta and sup erior m esenteric artery. • The abdom inal aorta is shorter and sm aller in caliber than the inferior vena cava. • The inferior m esenteric artery arises about 4 cm sup erior to the aortic bifurcation and crosses the left com m on iliac vessels to becom e the superior rectal artery. • The left renal vein drains the left testis, left suprarenal gland, and left kidney; the renal arteries are p osterior to the renal veins. • The ureter crosses the external iliac artery just beyond the com m on iliac bifurcation. • The testicular vessels cross anterior to the ureter and join the ductus deferens at the deep inguinal ring. • The left renal vein and duodenum (and uncinate p rocess of pancreas—not shown) pass between the aorta posteriorly and the superior m esenteric artery anteriorly; they m ay be com pressed like nuts in a nutcracker ( B) .

Ab d o m e n

358

POSTERIOR ABDOMINAL VISCERA

Peritoneum

Diaphragmatic surface

Splenic recess

9th rib Spleen Intercostal muscles Perinephric fat

Renal surface

10th rib

Right suprarenal gland

Renal fascia (anterior layer) Diaphragm

Splenorenal ligament containing branches of splenic artery and vein

Costodiaphragmatic recess 11th rib

Splenic artery and vein

Left kidney Tail of pancreas

Extra peritoneal fat of abdominal wall

Renal artery and veins entering renal sinus Paranephric fat

12th rib

Accessory renal artery Ureter

A. Anteromedial View with Spleen Reflected to Right

Gastrosplenic ligament Stomach

Spleen (reflected)

Visceral peritoneum (covering spleen) Parietal peritoneum

Splenic artery

Splenorenal ligament (cut)

Spleen Abdominal aorta Splenorenal ligament

Renal vein

Splenic artery

Left kidney

Renal vein Left kidney

B. Inferior View

4.69

Abdominal aorta

Site of incision Renal fascia (anterior layer)

Renal fascia (anterior layer)

C. Inferior View

EXPOSURE OF THE LEFT KIDNEY AND SUPRARENAL GLAND

A. Dissection. B. Schem atic section with spleen and splenorenal ligam ent intact. C. Procedure used in A to expose the kidney. The spleen and splenorenal ligam ent are re ected anteriorly, with the splenic vessels and tail of the pancreas. Part of the renal fascia of

the kidney is rem oved. Note the proxim ity of the splenic vein and left renal vein, enabling a sp le n o re n al sh un t to be established surgically to relieve portal hypertension.

KIDNEYS

Ab d o m e n Spleen

Left suprarenal gland

Left kidney

Left kidney 11th rib

L2

12th rib

Major calyx Renal pelvis 1

Inferior vena cava

Ureter

Abdominal aorta L5

Sacrum

1

Gas in intestine

L5 Ureter

Hip bone 2 External iliac artery

Urinary bladder

3 Urinary bladder

Urethra

A. Anterior View

B. Anteroposterior Pyelogram

Aortic hiatus in diaphragm

359

2

3

Left inferior phrenic artery Left superior suprarenal arteries Left suprarenal gland Left kidney Left middle suprarenal artery Left inferior suprarenal artery Left renal artery Left ureter Abdominal aorta Left gonadal artery (testicular or ovarian)

Left common iliac artery

C. Anterior View

Left internal iliac artery

KIDNEYS AND SUPRARENAL GLANDS

4.70

A. Overview of urinary system . B. Retrograde p yelogram . Contrast m ed ium was injected into the ureters from a exible endoscope (urethroscope) in the bladder. Note the papillae bulging into the m inor calices, which em pty into a m ajor calyx that opens, in turn, into the renal pelvis drained by the ureter. Sites at which relative constrictions in the ureters norm ally appear: (1) ureteropelvic junction; (2) crossing external iliac vessels or pelvic brim ; and (3) as ureter traverses bladder wall. These constricted areas are potential sites of obstruction by ureteric (kidney) stones. C. Arterial sup ply of the suprarenal glands, kidneys, and ureters. Re n al t ran sp lan t at io n is now an established op eration for the treatm ent of selected cases of chronic renal failure. The kidney can b e rem oved from the d onor without dam aging the suprarenal gland because of the weak sep tum of renal fascia that separates the kidney from this gland. The site for transplanting a kidney is in the iliac fossa of the greater pelvis. The renal artery and vein are joined to the external iliac artery and vein, respectively, and the ureter is sutured into the urinary bladder.

Ab d o m e n

360

KIDNEYS

Superior pole Medial margin

LATERAL

Anterior surface

MEDIAL Renal artery Renal vein

Posterior and anterior lips ANTERIOR

POSTERIOR

Renal sinus Renal pelvis Medial margin Posterior surface Inferior pole

Ureter

B. Anteromedial View

A. Anterior View

Fibrous capsule

Renal column Renal papilla

Renal cortex Minor calyx Renal medulla

Minor calyces Major calyx Major calyx

Renal column Renal sinus

Perinephric fat

Renal pelvis

Renal pelvis

Renal papilla

Ureter

Renal pyramid Renal pyramid Renal cortex

C. Anterior View

4.71

Ureter

D. Coronal Section

STRUCTURE OF KIDNEY

A. External features. The sup erior pole of the kidney is closer to the m edian plane than the inferior pole. Approxim ately 25% of kidneys m ay have a 2nd, 3rd, and even 4th accessory renal artery branching from the aorta. These m ultiple vessels enter through the renal sinus or at the superior or inferior pole (polar arteries). B. Renal sinus. The renal sinus is a vertical “p ocket” op ening on the m edial side of the kidney. Tucked into the pocket are the renal

pelvis and renal vessels in a m atrix of perinephric fat. C. Renal calices. The anterior wall of the renal sinus has been cut away to expose the renal pelvis and the calices. D. Internal features. Cyst s in t h e kid n e y, m ultip le or solitary, are com m on and usually benign ndings during ultrasound exam inations and dissection of cadavers. Ad ult p o lycyst ic d ise ase of the kidneys, however, is an im p ortant cause of renal failure.

KIDNEYS

Ab d o m e n

361

11th and 12th ribs

Superior segmental artery Anterosuperior segmental artery

Superior pole

Antero-inferior segmental artery

Inferior suprarenal artery Renal artery

Posterior segmental artery

Right Kidney, Anterior View

A

Interlobar artery

Inferior segmental artery

Right Kidney, Posterior View Inferior pole

Renal Segments: Apical

Posterior

Anterosuperior

Inferior

B. Anteroposterior Arteriogram

Antero-inferior Collecting duct Papillary duct Renal papilla

Interlobular Arcuate Interlobar

Lobar Posterior segmental

Renal corpuscle

Proximal Glomerular capsule convoluted Glomerulus tubule

Efferent glomerular arteriole

Distal Peritubular convoluted capillaries tubule

Minor calyx

Afferent glomerular arteriole Interlobular artery

Interlobular vein Renal cortex

Interlobar artery and vein Interlobar

Arcuate vein and artery Nephron loop (Loop of Henle)

C. Anterior View

Descending limb Ascending limb

Collecting duct

Vasa recta

Renal medulla

Papillary duct

D. Schematic Diagram

SEGMENTS OF THE KIDNEYS A. Segm ental arteries. Segm ental arteries do not anastom ose signi cantly with other segm ental arteries; they are end arteries. The area supp lied by each segm ented artery is an independent, surgically respectable unit or re n al se g m e n t . B. Renal arteriogram .

4.72 C. Corrosion cast of posterior segm ental artery of kidney. D. The nep hron is the functional unit of the kidney consisting of a renal corpuscle, p roxim al tubule, nephron loop, and distal tubule. Pap illary ducts open onto renal papillae, em ptying into m inor calices.

Ab d o m e n

362

KIDNEYS

Ureter

Bifid pelvis

Bifid pelvis

Unilateral duplicated ureter

A. Bifid Pelves

Ureter Junction of bifid ureter

B. Bifid Ureter and Unilateral

Bladder

Duplicated Ureter

Anteroposterior Pyelogram

Inferior vena cava

Right kidney

Abdominal aorta

Anomalous renal vessels

Ectopic kidney

Inferior vena cava

Inferior mesenteric artery

Right ureter

C. Retrocaval Ureter

D. Horseshoe Kidney

Left ureter Right ureter

E. Ectopic Pelvic Kidney Anterior Views

4.73

ANOMALIES OF KIDNEY AND URETER

A. Bi d p elves. The p elves are alm ost rep laced b y two long m ajor calices, which extend outsid e the sinus. B. Dup licated , or b i d, ureters. These can be unilateral or bilateral and com plete or incom p lete. C. Retrocaval ureter. The ureter courses posterior and then anterior to the inferior vena cava. D. Horseshoe kidney.

The right and left kidneys are fused in the m idline. E. Ectopic p elvic kid ney. Pelvic kidneys have no fatty cap sule and can be unilateral or b ilateral. During child b irth, they m ay cause ob struction and suffer injury.

POSTEROLATERAL ABDOMINAL WALL

Ab d o m e n

363

Latissimus dorsi

Serratus posterior inferior

12th rib

External oblique

Internal oblique Thoracolumbar fascia Lateral cutaneous branch of T12 nerve Iliac crest Lateral cutaneous branch of L1 nerve

Cutaneous branches of posterior rami of nerves L1, L2, L3

Posterolateral View

Latissimus dorsi

Iliac crest

POSTEROLATERAL ABDOMINAL WALL: EXPOSURE OF KIDNEY I

4.74

The latissim us dorsi is partially re ected. • The external oblique m uscle has an oblique, free posterior border that extends from the tip of the 12th rib to the m idpoint of the iliac crest. • The internal oblique m uscle extends posteriorly beyond the border of the external oblique m uscle.

364

Ab d o m e n

POSTEROLATERAL ABDOMINAL WALL

Latissimus dorsi

Serratus posterior inferior

12th rib

Subcostal nerve (T12) External oblique Internal oblique Aponeurosis of transversus abdominis Iliohypogastric nerve (L1)

Posterolateral View

Latissimus dorsi

4.75

POSTEROLATERAL ABDOMINAL WALL: EXPOSURE OF KIDNEY II

Iliac crest

The external oblique m uscle is incised and re ected laterally, and the internal oblique m uscle is incised and re ected m edially; the transversus abdom inis m uscle and its p osterior aponeurosis are exposed where p ierced by the subcostal (T12) and iliohyp ogastric (L1) nerves. These nerves give off m otor twigs and lateral cutaneous branches and continue anteriorly between the internal oblique and transversus abdom inis m uscles.

4.76

POSTEROLATERAL ABDOMINAL WALL: EXPOSURE OF KIDNEY III AND RENAL FASCIA (next page)

A. The posterior aponeurosis of the transversus ab dom inis m uscle is divided between the subcostal and iliohypogastric nerves and lateral to the oblique lateral border of the quadratus lum borum m uscle; the retroperitoneal fat surrounding the kidney is exposed.

B. Renal fascia and retroperitoneal fat, schem atic transverse section. The renal fascia is within this fat; fat internal to the renal fascia is term ed perinephric fat (perirenal fat capsule), and the fat im m ediately external is paranephric fat (pararenal fat body).

POSTEROLATERAL ABDOMINAL WALL

Erector spinae

Ab d o m e n

12th rib

Lumbar fascia, middle and posterior layers Right kidney

Subcostal nerve

Perinephric fat Transversus abdominis (aponeurotic origin)

Renal fascia Quadratus lumborum

Iliohypogastric nerve

A. Posterolateral View

Renal hilum

Peritoneum

Renal sinus Renal fascia (anterior layer)

Body of lumbar vertebra Psoas fascia (sheath)

Perinephric fat (perirenal fat capsule)

Psoas major

Transversus abdominis

Kidney Internal oblique Transverse process of lumbar vertebra

External oblique

Anterior layer of thoracolumbar fascia (quadratus lumborum fascia)

Paranephric fat (pararenal fat body) Aponeurotic origin of transversus abdominis Renal fascia (posterior layer) Latissimus dorsi

Deep back muscles Thoracolumbar fascia (posterior and middle layers)

B. Transverse Section, Inferior View

Quadratus lumborum

365

Ab d o m e n

366

POSTEROLATERAL ABDOMINAL WALL Esophageal hiatus

Diaphragm Aortic hiatus

Medial and lateral arcuate ligaments 12th rib

12th rib Left crus

Subcostal nerve

of Right crus diaphragm

Iliohypogastric nerve Genitofemoral nerve Ilio-inguinal nerve

Lumbar plexus

Quadratus lumborum

GR

Lateral cutaneous nerve of thigh Obturator nerve

Transversus abdominis Psoas minor Iliacus

Lumbosacral trunk

Psoas major

GR

Sympathetic trunk

Genitofemoral nerve

GR

Femoral branch

Sciatic nerve

Genital branch

Psoas major (cut end)

Femoral nerve

GR = Gray ramus communicans

Anterior View

4.77

LUMBAR PLEXUS AND VERTEBRAL ATTACHMENT OF DIAPHRAGM

TABLE 4.7

a

PRINCIPAL MUSCLES OF POSTERIOR ABDOMINAL WALL

Muscle

Superior Atta chments

Inferior Atta chments

Innerva tion

Actions

Psoas majora,b

Transverse processes of lumbar vertebrae; sides of bodies of T12–L5 vertebrae and intervening intervertebral discs

By a strong tendon to lesser trochanter of femur

Anterior rami of lumbar nerves (L1 c, L2 c, L3)

Acting inferiorly with iliacus, it exes thigh at hip; acting superiorly, it exes vertebral column laterally; it is used to balance the trunk; during sitting, it acts inferiorly with iliacus to ex trunk

Iliacusa

Superior two thirds of iliac fossa, ala of sacrum, and anterior sacro-iliac ligaments

Lesser trochanter of femur and shaft inferior to it, and to psoas major tendon

Femoral nerve (L2 c, L3, L4)

Flexes thigh and stabilizes hip joint; acts with psoas major

Quadratus lumborum

Medial half of inferior border of 12th rib and tips of lumbar transverse processes

Iliolumbar ligament and internal lip of iliac crest

Anterior rami of T12 and L1–L4 nerves

Extends and laterally exes vertebral column; xes 12th rib during inspiration

Psoas major and iliacus muscles are often described together as the iliopsoas muscle when exion of the hip joint is discussed. Psoas minor attaches proximally to the sides of bodies of T12–L1 vertebrae and intervertebral disc and distally to the pectineal line and iliopectineal eminence via the iliopectineal arch; it does not cross the hip joint. It is used to balance the trunk, in conjunction with psoas major. Innervation is from the anterior rami of lumbar nerves (L1, L2). c Primary segment(s) of innervation are boldface type. b

POSTEROLATERAL ABDOMINAL WALL

Ab d o m e n

367

Quadratus lumborum Iliohypogastric nerve (L1)

Ramus communicans

Ilio-inguinal nerve (L1)

Obturator nerve (L2, L3, L4)

Iliac crest

Lumbosacral trunk (L4, L5)

Sympathetic trunk

Lateral cutaneous nerve of thigh (L2, L3)

Sciatic nerve (L4, L5, S1, S2, S3) Pudendal nerve (S2, S3, S4)

Femoral branch of genitofemoral nerve (L1, L2)

Genital branch of genitofemoral nerve (L1, L2)

Ganglion impar Femoral nerve (L2, L3, L4)

Common fibular nerve (L4, L5, S1, S2) Posterior Anterior Tibial nerve (L4, L5, S1, S2, S3)

Branches of obturator nerve (L2, L3, L4)

A. Anterior View

NERVES OF LUMBAR PLEXUS The lum bar plexus of nerves is com posed of the anterior ram i of L1–L4 nerves: • Ilio-inguinal and iliohypogastric nerves (L1) enter the abdom en posterior to the m edial arcuate ligam ents; they run between the transversus abdom inis and internal oblique to supply the skin of the suprapubic and inguinal regions. • Lateral cutaneous nerve of thigh (L2, L3) enters the thigh p osterior to the inguinal ligam ent, just m edial to the anterior superior iliac spine; it supplies the skin on the anterolateral surface of the thigh.

4.78 • Fem oral nerve (L2–L4) em erges from the lateral border of the psoas; innervates the iliacus m uscle and the extensor m uscles of the knee. • Genitofem oral nerve (L1, L2) pierces the anterior surface of the psoas m ajor m uscle; divides into fem oral and genital branches. • Obturator nerve (L2–L4) em erges from the m edial border of the psoas to supply the adductor m uscles of the thigh. • Lum bosacral trunk (L4, L5) passes over the ala of the sacrum to join the sacral plexus.

368

Ab d o m e n

DIAPHRAGM

Sternal origin

Anteromedian gap Anterolateral gap

Costal origin

Central tendon

Caval opening

Esophageal hiatus

Median arcuate ligament Aortic hiatus

Gap for psoas major Medial arcuate ligament Lumbocostal triangle Lateral arcuate ligament

12th rib

Quadratus lumborum

A. Inferior View

Left crus

Right crus

Thoracic aorta Central tendon Sternum

Median arcuate ligament

Level of: T8

Celiac trunk Diaphragm

Hepatic artery proper Common hepatic artery Gastroduodenal artery Right renal artery Right crus

Splenic artery Left crus

B. Anterior View

Esophageal hiatus

Esophagus

Superior mesenteric artery Abdominal aorta

T10

Inferior vena cava

Left renal artery

Inferior mesenteric artery

4.79

Caval opening

Abdominal aorta

T12

Aortic hiatus

Celiac trunk Superior mesenteric artery

C. Lateral View, from Left

DIAPHRAGM

A. Dissection. The clover-shaped central tendon is the aponeurotic insertion of the m uscle. Diap h rag m at ic h e rn ia. The diaphragm in this specim en fails to arise from the left lateral arcuate ligam ent, leaving a potential opening, the lum bocostal triangle, through which abdom inal contents m ay be herniated into the thoracic cavity following a sudden increase in intra-thoracic or intra-abdom inal pressure. A h iat al h e rn ia is a protrusion of part of the stom ach into the thorax through the esophageal hiatus.

B. Median arcuate ligam ent and branches of the aorta. C. Openings of the diaphragm . There are three m ajor openings: (1) the caval opening for the inferior vena cava, m ost anterior, at the T8 vertebral level to the right of the m idline; (2) the esophageal hiatus, interm ediate, at T10 level and to the left; and (3) the aortic hiatus, which allows the aorta to pass posterior to the vertebral attachm ent of the diap hragm in the m idline at T12.

ABDOMINAL AORTA AND INFERIOR VENA CAVA

Azygos vein Inferior phrenic artery (T12)

Celiac trunk (T12)

Superior mesenteric artery (L1)

Subcostal artery (L1)

Lumbar arteries: (L1–L4)

Right common iliac artery

Right inferior phrenic vein

Aortic hiatus Suprarenal artery (L1) 1st

Left renal artery (L1)

2nd

Testicular or ovarian arteries (L2)

3rd

Inferior mesenteric artery (L3)

4th

Abdominal aorta

Inferior vena cava Right suprarenal vein Right renal vein

1st

Lumbar 3rd veins 4th

Median sacral artery Left common

5th

Left external Iliac artery Left internal

A. Anterior View

Inferior phrenic Suprarenal: Superior Middle Right renal Lumbar Abdominal aorta Median sacral Deep circumflex iliac Inferior epigastric

369

Right Intermediate Hepatic veins (middle) Left Hemi-azygos vein Left inferior phrenic vein Posterior intercostal veins

2nd

Bifurcation of abdominal aorta (L4)

Ab d o m e n

B. Anterior View

Left suprarenal vein Left renal vein Left gonadal vein (testicular or ovarian) Right gonadal vein (testicular or ovarian) Ascending lumbar vein Left common iliac vein Left external iliac vein Left internal iliac vein Median sacral vein Right common iliac vein

Celiac Superior mesenteric Subcostal Left renal Left gonadal (testicular or ovarian) Inferior mesenteric Left common iliac

Transpyloric plane

Abdominal aorta

Highest point of iliac crest

Aortic bifurcation

External iliac artery

Internal iliac

Common iliac artery Internal iliac artery

External iliac Femoral

D. Anterior View

C. Anterior View Branches of Abdominal Aorta Anterior midline

Lateral

Posterolateral

ABDOMINAL AORTA AND INFERIOR VENA CAVA AND THEIR BRANCHES A. Branches (and their vertebral levels) of abdom inal aorta. B. Tributaries of the inferior vena cava (IVC). C. Arteries of p osterior abd om inal wall, branches of aorta. D. Surface anatom y. Rupture of an ao rt ic an e urysm (localized enlarg em ent of the abd om inal aorta) causes severe pain in the abdom en or back. If unrecognized, a ruptured aneurysm has a m ortality of nearly 90%

4.80

because of heavy blood loss. Surgeons can repair an aneurysm by opening it, inserting a p rosthetic graft (such as one m ade of Dacron), and sewing the wall of the aneurysm al aorta over the graft to protect it. Aneurysm s m ay also be treated by endovascular catheterization procedures.

Ab d o m e n

370

AUTONOMIC INNERVATION

Innervation

Diaphragm

Sympathetic Parasympathetic Plexus (sympathetic and parasympathetic Sacral plexus (somatic)

Fibers from anterior vagal trunk Stomach (cut edge)

Fibers from posterior vagal trunk Sympathetic fibers to stomach

Greater

Celiac ganglion/plexus Celiac trunk

Lower thoracic splanchnic nerves Lesser

Superior mesenteric ganglion and artery

Least

Aorticorenal ganglion and renal plexus

Inferior mesenteric ganglion/plexus and artery

Intermesenteric plexus Lumbar splanchnic nerves

Sympathetic trunk and ganglion Superior hypogastric plexus

Hypogastric nerve

Internal iliac artery Inferior hypogastric plexus Pelvic splanchnic nerves External iliac artery Sciatic nerve Pudendal nerve Anterior View

4.81

ABDOMINOPELVIC NERVE PLEXUSES AND GANGLIA

Th e sym p at h e t ic p art o f t h e aut o n o m ic n e rvo us syst e m in t h e ab d o m e n co n sist s o f: • Abdominopelvic splanchnic nerves from the thoracic and abdom inal sym p athetic trunks. • Preverteb ral sym p athetic ganglia.

• Abdominal aortic plexus and its extensions, the peri-arterial plexuses. The plexuses are m ixed, shared with the parasym pathetic nervous system and visceral afferent bers.

AUTONOMIC INNERVATION

Celiac ganglion

Sympathetic fibers to stomach

Ab d o m e n

Fibers from posterior vagal trunk

371

Fibers from anterior vagal trunk

Greater Splanchnic Lesser nerves Least Superior mesenteric ganglion

Celiac plexus Suprarenal plexus

Aorticorenal ganglion

Renal plexus Intermesenteric plexus

Inferior mesenteric ganglion

Abdominal aortic plexus

Sympathetic trunk and ganglion

Lumbar splanchnic nerves

Superior hypogastric plexus

Hypogastric nerve

* Nerves to descending and sigmoid colon

Inferior hypogastric (pelvic) plexus

Pelvic splanchnic nerves:

Inferior hypogastric (pelvic) plexus

Sacral splanchnic nerves

*

S2 S3 S4

Innervation Sympathetic Somatic (sacral plexus) Parasympathetic

A. Sympathetic Innervation

OVERVIEW OF AUTONOMIC NERVOUS SYSTEM A. Sym p athetic. B. Parasym pathetic.

Anterior Views

Innervation Parasympathetic Somatic (sacral plexus) Sympathetic

B. Parasympathetic Innervation

4.82

372

Ab d o m e n

AUTONOMIC INNERVATION

Nerves T5

Abdominopelvic splanchnic nerves

Visceral afferent Presynaptic sympathetic Postsynaptic sympathetic Presynaptic parasympathetic Postsynaptic parasympathetic

T6 T7

ganglia of * = Prevertebral abdominal aortic plexus

Greater splanchnic nerve Lesser splanchnic nerve Least splanchnic nerve

T8 T9 T10 T11

Vagus nerve (CN X)

*Celiac

T12

Diaphragm Liver

L1

Stomach

L2

*Aorticorenal ganglia

L3

Pancreas Suprarenal gland

Intermediolateral cell column (IML) Thoracolumbar spinal cord segments

Parasympathetic innervation via cranial outflow

ganglion

*Superior mesenteric ganglion Left colic flexure

Peri-arterial plexuses

Sympathetic trunk (paravertebral ganglia)

Kidney

Sacral spinal cord segments

Pelvic splanchnic nerves

Sympathetic innervation

Descending colon S2

A

Gonad

Prevertebral sympathetic ganglion

S4

*Inferior Peri-arterial plexus

Presynaptic parasympathetic (vagal) fiber

mesenteric ganglion

Intrinsic postsynaptic neuron

Pelvic plexus Parasympathetic innervation via sacral outflow

Longitudinal and circular layers (smooth muscle)

Visceral afferent fiber

Presynaptic sympathetic (splanchnic) fiber

S3

Lumbar splanchnic nerve

Postsynaptic sympathetic fiber

Submucosa

B

4.83

ORIGIN AND DISTRIBUTION OF PRESYNAPTIC AND POSTSYNAPTIC SYMPATHETIC AND PARASYMPATHETIC FIBERS, AND GANGLIA INVOLVED IN SUPPLYING ABDOMINAL VISCERA

A. Overview. B. Fibers supp lying the intrinsic p lexuses of abdom inal viscera.

Ab d o m e n

AUTONOMIC INNERVATION

Celiac ganglia

373

Fibers from posterior vagal trunk

Greater Splanchnic nerves Lesser

Left suprarenal gland Aorticorenal ganglion

Least

Renal plexus

Celiac trunk Left kidney

Right kidney

L1 Aorta

Superior mesenteric ganglion and artery

L2 L3

Lumbar splanchnic nerves

Left renal artery Intermesenteric plexus

L4

Inferior mesenteric artery and ganglion

Key Sympathetic Parasympathetic Mixed sympathetic and parasympathetic

Ureteric and testicular/ovarian plexus Superior hypogastric plexus

Sympathetic ganglion and trunk

Left common iliac artery and plexus

Right

Anterior View

Left

Hypogastric nerves to inferior hypogastric/pelvic plexus

4.84

ABDOMINAL NERVE PLEXUSES AND GANGLIA TABLE 4.8

a

AUTONOMIC INNERVATION OF ABDOMINAL VISCERA ( SPLANCHNIC NERVES)

Spla nchnic Nerves

Autonomic Fiber Typea

System

Origin

A. Cardiopulmonary (Cervical and upper thoracic)

Postsynaptic

Sympathetic

Cervical and upper thoracic sympathetic Thoracic cavity (viscera superior to the level of diaphragm) trunk

B. Abdominopelvic 1. Lower thoracic a. Greater b. Lesser c. Least 2. Lumbar 3. Sacral

Presynaptic

C. Pelvic

Presynaptic

Parasympathetic

Destina tion

Lower thoracic and abdominopelvic sympathetic trunk: 1. Thoracic sympathetic trunk: a. T5–T9 or T10 level b. T10–T11 level c. T12 level 2. Abdominal sympathetic trunk 3. Pelvic (sacral) sympathetic trunk

Abdominopelvic cavity (prevertebral ganglia serving viscera and suprarenal glands inferior to the level of diaphragm) 1. Abdominal prevertebral ganglia: a. Celiac ganglia b. Aorticorenal ganglia c. & 2. Other abdominal prevertebral ganglia (superior and inferior mesenteric and of intermesenteric/hypogastric plexuses) 3. Pelvic prevertebral ganglia

Anterior rami of S2–S4 spinal nerves

Intrinsic ganglia of descending and sigmoid colon, rectum, and pelvic viscera

Splanchnic nerves also convey visceral afferent bers, which are not part of the autonomic nervous system.

374

Ab d o m e n

AUTONOMIC INNERVATION

Liver, gallbladder, and duodenum (resulting from irritation of diaphragm)

Duodenum, head of pancreas

Gallbladder

Stomach Spleen

Gallbladder Liver

Liver Small intestine (pink)

Appendix

Sigmoid colon

Cecum and ascending colon

Kidney and ureter

A. Anterior View

B. Posterior View

L

St

(T6–T9)

(T6–T9)

Sp

SR

(T6– T8)

(T6–L2)

4.85

SURFACE PROJECTIONS OF VISCERAL PAIN

A. and B. Sites of visceral referred pain. C. Approxim ate spinal cord segm ents and spinal sensory ganglia involved in sym pathetic and visceral afferent (pain) innervation of abdom inal viscera. Pain is an unpleasant sensation associated with actual or potential tissue dam age, m ediated by speci c nerve bers to the brain, where its conscious appreciation m ay be m odi ed. Organic pain arising from an organ such as the stom ach varies from dull to severe; however, the pain is poorly localized. It radiates to the derm atom e level served by the corresponding sensory ganglion, which receives the visceral afferent b ers from the organ concerned. Visce ral re fe rre d p ain from a gastric ulcer, for exam ple, is referred to the epigastric region because the stom ach is supplied by pain afferents that reach the T7 and T8 spinal (sensory) ganglia and spinal cord segm ents through the greater splanchnic nerve. The brain interprets the pain as though the irritation occurred in the skin of the epigastric region, which is also supplied by the sam e sensory ganglia and spinal cord seg m ents. Pain arising from the p arietal peritoneum is of the som atic type and is usually severe. The site of its origin m ay be localized. The anatom ical basis for this localization of pain is that the parietal peritoneum is supplied by som atic sensory bers through thoracic nerves, whereas a viscus such as the appendix is supplied by visceral afferent bers in the lesser splanchnic nerve. Inam ed parietal peritoneum is extrem ely sensitive to stretching . When digital pressure is app lied to the anterolateral abdom inal wall over the site of in am m ation, the p arietal peritoneum is stretched. When the ngers are sud denly rem oved, extrem e localized pain is usually felt, known as re b o un d t e n d e rn e ss.

P

(T6–T9)

RK

P

(T10–L1)

LK

(T10–L1)

(T6–T9)

D

(T8–T10)

TC (T11)

DC (T12–L1) SI(T8–T10)

SI(T8–T10)

SC (L2–L3)

C

(T10)

(S2)

R

(S4)

C. Anterior View Key C

Cecum

P

Pancreas

Sp

Spleen

D

Duodenum

R

Rectum

SR Suprarenal glands

DC Descending colon

RK Right kidney

St

L

SC Sigmoid colon

TC Transverse colon

Liver

LK Left kidney

SI

Small intestine

Stomach

Ab d o m e n

AUTONOMIC INNERVATION

375

Sympathetic plexus on hepatic portal vein and left hepatic branch Lesser omentum, cut edge Hepatic branches Liver

Posterior vagal trunk (right vagus nerve)

Anterior vagal trunk (left vagus nerve) Right hepatic duct

Esophagus

Right hepatic branch Stomach

Left gastric artery accompanied by celiac branches of posterior vagal trunk Common hepatic artery Pancreas Left gastric artery Gastroduodenal artery

A. Anterior View

Right gastric artery

Esophageal hiatus Posterior vagal trunk Right inferior phrenic artery Celiac branch Right suprarenal gland

Left inferior phrenic artery Left gastric artery

Artery of capsule

Left suprarenal gland

Right kidney

Splenic artery, reflected

Left renal artery Left testicular artery

B. Antero-inferior View

Right renal artery and plexus

Right celiac ganglion

Left celiac ganglion Abdominal aorta

Superior mesenteric artery

VAGUS NERVES IN ABDOMEN A. Anterior and posterior vagal trunks. B. Celiac p lexus and ganglia and suprarenal glands.

4.86

Ab d o m e n

376

LYMPHATIC DRAINAGE

Diaphragm

Inferior vena cava (IVC) Esophagus

Celiac trunk

Central tendon of diaphragm Right suprarenal gland Left suprarenal gland Thoracic duct

Left kidney

Intestinal lymphatic trunk Superior mesenteric artery

Right kidney Abdominal aorta

Left lumbar lymphatic trunk

Cisterna chyli (chyle cistern)

Quadratus lumborum

Right lumbar lymphatic trunk

Left ureter (abdominal part) Inferior mesenteric artery

Transversus abdominis Psoas major

Right ureter (abdominal part)

Left common iliac artery and vein Right internal iliac vein and artery Iliacus

Right external iliac artery and vein

Left ureter (pelvic part) Right ureter (pelvic part) Rectum Bladder

A. Anterior View Key Inferior vena cava

Abdominal aorta

Left lumbar (aortic): Lateral aortic

Common iliac

Postaortic

External iliac

Pre-aortic

Inferior mesenteric

Right lumbar (caval): Lateral caval Postcaval

B. Anterior View

4.87

Celiac

Precaval

Internal iliac Intermediate lumbar Superior mesenteric Direction of flow of lymph Secondary (subsequent) drainage

LYMPHATIC DRAINAGE OF SUPRARENAL GLANDS, KIDNEYS, AND URETERS

Lym phatic vessels from the sup rarenal glands, kidneys, and up per ureters drain to the lum bar nodes. Lym phatic vessels from the m iddle part of the ureter usually drain into the co m m o n iliac lym p h

n o d e s, whereas vessels from its inferior part drain into the com m on, external, or internal iliac lym p h n o d e s.

LYMPHATIC DRAINAGE

Ab d o m e n

377

Ligature retracting suprarenal gland

Inferior phrenic artery Diaphragm

Celiac ganglion

Greater and lesser splanchnic nerves

Right kidney (posterior aspect)

Vein uniting inferior vena cava to azygos vein

Right crus of diaphragm

Medial arcuate ligament Probe retracting inferior vena cava

Cisterna chyli Abdominal aorta

Right lumbar lymphatic trunk Rami communicantes Right lumbar (caval) lymph nodes Sympathetic ganglion Transverse process (L3) Transversalis fascia

Lumbar splanchnic nerve

Transverse process (L4)

Ascending colon (posterior aspect)

Psoas major

Iliac crest

Common iliac lymph node

Ureter Tendon of psoas minor

Inferior vena cava Common iliac artery

Anterior View

Lymph vessels

LUMBAR LYMPH NODES, SYMPATHETIC TRUNK, NERVES, AND GANGLIA The right suprarenal gland, kidney, ureter, and colon are re ected to the left along with the transversalis fascia covering their posterior aspects. The inferior vena cava is pulled m edially, and the third and fourth lum bar veins are rem oved. In this specim en, the greater and lesser splanchnic nerves, the sym pathetic trunk, and a

4.88

com m unicating vein pass through an unusually wide cleft in the right crus. The splanchnic nerves convey preganglionic bers arising from the cell bodies in the (thoracolum bar) sym pathetic trunk. The greater splanchnic nerve is from thoracic ganglia 5 to 9, and the lesser from thoracic ganglia 10 and 11.

Ab d o m e n

378

LYMPHATIC DRAINAGE

Left gastric artery

Stomach

Spleen Celiac trunk Splenic artery

Celiac trunk Splenic artery Superior mesenteric artery

Superior mesenteric artery Pancreas Abdominal aorta

Duodenum

B. Anterior View

Right lymphatic duct

Left internal jugular vein Thoracic duct Left subclavian vein

From ileum From jejunum Thoracic aorta Diaphragm

Thoracic duct

A. Anterior View Key for A and B Celiac

Pancreaticosplenic

Gastric

Pyloric

Gastro-omental

Initial drainage

Hepatic

Secondary

Mesenteric

(subsequent) drainage

Pancreaticoduodenal

Aortic hiatus Abdominal aorta Cisterna chyli (chyle cistern) Right lumbar lymphatic trunk

Intestinal lymphatic trunk Left lumbar lymphatic trunk

C. Anterior View

4.89

LYMPHATIC DRAINAGE

A. Stom ach and sm all intestine. B. Spleen and pancreas. C. Drainage from lum bar and intestinal lym phatic trunks. The arrows indicate the direction of lym ph ow; each group of lym ph nodes is colorcoded. Lym ph from the abdom inal nodes drains into the cisterna

chyli, origin of the inferior end of the thoracic duct. The thoracic duct receives all lym ph that form s inferior to the diaphragm and left upper quadrant (thorax and left upper lim b) and em pties into the junction of the left subclavian and left internal jugular veins.

Ab d o m e n

LYMPHATIC DRAINAGE

379

Epicolic nodes Lymph Nodes for D and E: Middle colic lymph nodes

Appendicular Celiac Cystic Epicolic Hepatic Ileocolic Inferior mesenteric Intermediate colic (right, left, middle colic) Lateral aortic Left gastric Lumbar Mediastinal Paracolic Phrenic Superior mesenteric Direction of flow of lymph

Left colic flexure

Middle colic artery

Left colic lymph nodes

Right colic artery and lymph nodes Ileocolic artery Left colic artery

Cecum

Appendix

D. Anterior View

Inferior mesenteric artery

Thoracic aorta Posterior mediastinal lymph nodes

Caval opening in diaphragm

Coronary ligament Bare area of liver

Diaphragm

Inferior vena cava

Hepatic veins entering IVC in bare area of liver

Esophageal hiatus in diaphragm

Liver

Left gastric artery Hepatic artery

Cystic duct

Hepatic portal vein Splenic artery Common hepatic artery Left renal artery

Gallbladder

Superior mesenteric Abdominal artery Inferior vena aorta cava (IVC)

E. Anterior View

LYMPHATIC DRAINAGE (continued ) D. Large intestine. E. Liver and gallblad der. F. Liver.

Parasternal lymph nodes Sternum

Posterior superior diaphragmatic lymph nodes

Anterior superior diaphragmatic lymph nodes

Posterior Inferior diaphragmatic (phrenic) nodes

Anterior Hepatic artery

Right suprarenal gland

Falciform ligament

Celiac lymph nodes

Hepatic lymph nodes

Celiac trunk Pyloric antrum

Abdominal aorta Right kidney Superior lumbar lymph nodes

Superior mesenteric artery

Pancreas

Superior mesenteric lymph nodes

F. Lateral View

4.89

Ab d o m e n

380

SECTIONAL ANATOMY AND IMAGING

cc cc

cc

cc

RA

RIL R

Xp

R

cc cc

cc

cc

D

R

LL

R

LHV

R E

IVC

PV RHV R R IL

SC

R

IHV

CL

RHV IVC Az

St

Az

R

RIL

R

LIL

Ao

R

St

R

Hz Sp LIL

R

R

S

E

T10

Hz TV P

R

LHV

RL

Ao

T10

RL

R

LL

R IHV

cc

R

DBM

DBM

B

A

AF

LL CD GB

AF R

FL HA

R

RK

T12

D2

Ao Az L C

RL

R

RC

Hz

P PV

IVC RG

CHA

CL

PV

Sp

RF

RK

IVC Ao RC Az L1

DBM

SV

LG

LK

R

PF LC

R

R

SA

CA

PF S

R

St

Ac St

CHD

PA

R

R Sp

R

D

C Key

A

B

T11

C E

D F

H

G L4 L5

4.90

Ac AF Ao Az CA cc CD CHA CHD CL D DBM

Ascending colon Air-fluid level of stomach Aorta Azygos vein Celiac artery Costal cartilage Cystic duct Common hepatic artery Common hepatic duct Caudate lobe of liver Diaphragm Deep back muscles

TRANSVERSE (AXIAL) MRIs OF ABDOMEN

Dc D2 D3 E FL GB HA Hz IHV IMV IVC LC

Descending colon Descending part of duodenum Inferior part of duodenum Esophagus Falciform ligament Gallbladder Hepatic artery Hemi-azygos vein Intermediate hepatic vein Inferior mesenteric vein Inferior vena cava Left crus of diaphragm

LG LHV LIL LK LL LRV LU P PA PB PC

Left suprarenal gland Left hepatic vein Left inferior lobe of lung Left kidney Left lobe of liver Left renal vein Left ureter Pancreas Pyloric antrum of stomach Body of pancreas Portal confluence

Ab d o m e n

SECTIONAL ANATOMY AND IMAGING

RA

RA

381

RA

RA

AF PA

R

St SA

Ac

R

PH R RRV

PC

SV

IVC RC

D2

Sp

LC

Hz

Ac

R

Ao L1

RK

R

SF

PT

Tc

Tc

R

PB

SMV SMA PH PU Ao IVC L2

RK

R

R

TVP

R

PB

Tc

R Dc

PS

PS

LK

R

Tc

St

LK

R

R

R

R

RRA

RRV

DBM

S

DBM

LRV

Az

F

E

SMV

RA Tc Tc

Tc Tc SMA

SMA

SI

SI D3 D3

Ac RK

IMV

Ac IVC Ao PS

Dc RP

L3

R

RU

IVC Ao RC

RL

R

PS

PS R

PF

L2

QL

LRV

R

Dc

LK

PS

R

QL

TVP DBM

DBM

SI

LU RP

RK

LK QL

D2

S

DBM

S

G

H

Key (continued) PF PH PS PT PU PV QL R RA

Perinephric fat Head of pancreas Psoas muscle Tail of pancreas Uncinate process of pancreas Hepatic portal vein Quadratus lumborum Rib Rectus abdominis

RC RF RG RHV RIL RK RL RP RRA

Right crus of diaphragm Retroperitoneal fat Right suprarenal gland Right hepatic vein Right inferior lobe of lung Right kidney Right lobe of liver Renal pelvis Right renal artery

TRANSVERSE (AXIAL) MRIs OF ABDOMEN (continued )

RRV RU S SA SC SF SI SMA SMV

Right renal vein Right ureter Spinous process Splenic artery Spinal cord Splenic flexure Small intestine Superior mesenteric artery Superior mesenteric vein

Sp St SV Tc TVP Xp

Spleen Stomach Splenic vein Transverse colon Transverse process Xiphoid process

4.90

Ab d o m e n

382

SECTIONAL ANATOMY AND IMAGING

Right lung

Splenic artery

Left lung

Left lobe of liver (LL) Right lobe of liver (RL)

RL

Stomach (St)

LL St

Spleen (Sp)

Hepatic portal vein (PV)

PV

Sp

P SV SMV

Splenic vein (SV)

P

Superior mesenteric vein (SMV)

Pancreas (P) Duodenum (D)

SI

Small intestine (SI)

A. Anterior View (Formation of Portal Vein)

Right dome of diaphragm (RDD)

Middle hepatic vein (MHV)

Celiac artery (CA)

Dc

B. Coronal MRI through Portal Vein

RDD Right lung Esophageal hiatus

MHV

Superior mesenteric vein

Esophagus

Spleen (Sp) Splenic artery (SA)

Right kidney (RK)

Left renal vein (LRV)

Right lobe of liver

Sp CA IVC

LRV

LK

RK Ao

Abdominal aorta (Ao) Aortic bifurcation (AB) Left common iliac artery (LCI)

C. Anterior View (Posterior Abdominal Wall)

PS

R C I

AB I LC

Right common iliac artery (RCI)

SA

SV

SMA

Left kidney (LK)

Psoas (PS)

Left lung

LDD

Splenic vein (SV)

Inferior vena cava (IVC)

Stomach

Left dome of diaphragm (LDD)

Superior mesenteric artery (SMA)

4.91

D

Descending colon (Dc)

PS

D. Coronal MRI through Inferior Vena Cava

CORONAL MRIs OF ABDOMEN

A. Illustration of form ation of the hepatic portal vein. B. Coronal MRI through hepatic portal vein. C. Illustration of posterior

abdom inal wall. D. Coronal MRI through inferior vena cava and right and left kidneys.

Ab d o m e n

SECTIONAL ANATOMY AND IMAGING

383

Abdominal aorta

Inferior vena cava

LIL

Spleen

Porta hepatis

LL

GE

RC Splenic vein

Hepatic portal vein

T12

Ao St

P

SV

CA L1 A SM

Left renal vein

Right kidney

L2 Tc

Do L3

Inferior mesenteric vein

S Superior mesenteric vein

LRV

L4 R

L

C. Sagittal MRI through Aorta andABo Celiac and Superior Mesenteric Arteries

I Right common iliac vein

Key for C:

Left common iliac artery Left common iliac vein

Right common iliac artery

Ao CA Do GE LIL LL LRV

A. MR Angiogram (Portal Venogram)

Heart

Aorta Celiac artery Duodenum Gastro-esophageal junction Inferior lobe of left lung Left lobe of liver Left renal vein

P RC SMA St SV Tc

Pancreas Right crus Superior mesenteric artery Stomach Splenic vein Transverse colon

Celiac artery Splenic artery Celiac trunk Abdominal aorta

Left Artery renal Vein

Left renal artery

Right kidney

Left kidney

Right renal artery

Superior mesenteric artery 3rd part of duodenum

Small intestine Right common iliac artery

Left common iliac vein

Superior mesenteric artery

B. MR Angiogram of Aorta and Its Branches

MR ANGIOGRAMS AND SAGITTAL MRI OF ABDOMEN A. Magnetic resonance angiogram (p ortal venogram ) dem onstrating the tributaries and form ation of the hepatic portal vein. B. MR angiogram of aorta and b ranches. C. Sagittal MRI through aorta

Aorta

D. Lateral View (from Left)

4.92 showing the relationships of the celiac and superior m esenteric arteries to surrounding structures. D. Schem atic illustration of relationships of superior m esenteric artery.

Ab d o m e n

384

Falciform ligament

SECTIONAL ANATOMY AND IMAGING

Hepatic artery

Liver

Pancreas Celiac artery

Hepatic portal vein

Splenic artery

Inferior vena cava

Vertebral body

Right crus of diaphragm

A. Transverse US Scan through Celiac Axis (Area of Branching) Gastroduodenal artery

Portal venous confluence

Aorta

Pancreas

Liver Duodenum

Bile duct

Splenic vein

Vertebral body Splenic Uncinate process artery (pancreas) B. Transverse US Scan through Splenic View Inferior vena cava

Left gastric artery

Liver

Splenic artery

Abdominal aorta

Splenic vein

Pancreas

Vein Superior Artery mesenteric

inal Abdom aorta

Gastro-esophageal junction

Celiac artery (trunk)

Left renal vein

C. Midsagittal US Scan through Abdominal Aorta

4.93

ULTRASOUND SCANS OF ABDOMEN

A. Transverse ultrasound scan through celiac artery (axis). B. Transverse ultrasound scan through pancreas. C. and D. Sagittal ultrasound scans through the aorta, celiac trunk, and superior m esenteric

artery (D with Doppler). E. Transverse ultrasound scan at hilum of left kidney with the left renal artery and vein (with Doppler). F. Sagittal ultrasound scan of the right kidney.

SECTIONAL ANATOMY AND IMAGING

Ab d o m e n

385

Liver Superior mesenteric artery Celiac artery

Abdominal aorta

D. Midsagittal US Scan

Cortex of kidney Segmental artery Perirenal fat in renal sinus

Left renal vein Left renal artery

Hilum of kidney

E. Transverse US Scan

Liver

Perirenal fat in renal sinus

Cortex of kidney Psoas

F. Sagittal US Scan

ULTRASOUND SCANS OF ABDOMEN (continued ) A m ajor advantage of ultrasonography is its ability to produce realtim e im ages, dem onstrating m otion of structures and ow within blood vessels. In Doppler ultrasonography (D and E), the shifts in frequency between em itted ultrasonic waves and their echoes are

4.93 used to m easure the velocities of m oving objects. This technique is based on the principle of the Doppler effect. Blood ow through vessels is disp layed in color, sup erim p osed on the two-dim ensional cross-sectional im age (slow ow: blue, fast ow: orange).

CHAPTER 5

Pe lvis an d Pe rin e um Pelvic Girdle .......................................................................388 Ligam ents of Pelvic Girdle ..................................................395 Floor and Walls of Pelvis .....................................................396 Sacral and Coccygeal Plexuses ...........................................400 Peritoneal Re ections in Pelvis............................................402 Rectum and Anal Canal......................................................404 Organs of Male Pelvis ........................................................410 Vessels of Male Pelvis .........................................................416 Lym phatic Drainage of Male Pelvis and Perineum ..............418 Innervation of Male Pelvic Organs .....................................420 Organs of Fem ale Pelvis .....................................................422 Vessels of Fem ale Pelvis ......................................................432 Lym phatic Drainage of Fem ale Pelvis and Perineum ...........434 Innervation of Fem ale Pelvic Organs ..................................436 Subperitoneal Region of Pelvis ...........................................440 Surface Anatom y of Perineum ............................................442 Overview of Male and Fem ale Perineum ............................444 Male Perineum ..................................................................449 Fem ale Perineum ...............................................................458 Pelvic Angiography ............................................................466

Pe lvis an d Pe rin e um

388

PELVIC GIRDLE

Iliac crest Sacrum Anterior superior iliac spine (ASIS) Right hip bone Coccyx

Inguinal fold (dashed line) Pubic tubercle Pubic symphysis

A. Anterior View

Iliac crest Posterior superior iliac spine Sacrum Median sacral crest Left hip bone Inferolateral angle Coccyx

Sacral cornu

Ischial tuberosity

B. Posterior View

5.1

SURFACE ANATOMY OF MALE PELVIC GIRDLE

The pelvic girdle (bony pelvis) is a basin-shaped ring of three bones (right and left hip bones and sacrum) that connects the vertebral colum n to the fem ora. Palp ab le feat ures (green) sh ould b e sym m etrical across th e m id lin e. A. The anterior third of the iliac crests are subcutaneous and usually easily palpable. The rem ainder of the crests may also be palpable, depending on the thickness of the overlying

subcutaneous tissue (fat). The inguinal ligam ent spans between the palpable anterior superior iliac spine (ASIS) and pubic tubercle, located superior to the lateral and m edial ends of the inguinal fold. B. The posterior superior iliac spine (PSIS) is usually palpable and often lies deep to a visible dim ple, indicating the S2 vertebral level. The ischial tuberosities may be palpated when the hip joint is exed.

PELVIC GIRDLE

Sacro-iliac joint

Pe lvis an d Pe rin e um

389

Iliac crest

Sacrum Anterior superior iliac spine Right hip bone

Inguinal fold (dashed line)

Pubic symphysis Pubic tubercle

A. Anterior View

Iliac crest Posterior superior iliac spine Sacrum

Median sacral crest

Sacro-iliac joint Left hip bone Inferolateral angle Sacral cornu

Coccyx

Ischial tuberosity

Gluteal fold

B. Posterior View

SURFACE ANATOMY OF FEMALE PELVIC GIRDLE The fem ale p elvic g ird le is relatively wid er and shallower than that of the m ale, related to its ad d itional roles of b earing the weig h t of th e g ravid uterus in late p re g n a n cy an d allowing p assag e of the fetus throug h the p elvic outlet d uring child b irth (p a rt u rit io n ). A. Palp ab le features (green): The hip b ones are

5.2 joined anteriorly at the p ub ic sym p hysis. The p resence of a thick overlying p ub ic fat p ad form ing the m ons p ub is m ay interfere with p alp ation of th e p ub ic tub ercles and sym p h ysis. B. Posteriorly, th e h ip b on es articulate with th e sacrum at th e sacro-iliac joints.

390

Pe lvis an d Pe rin e um

PELVIC GIRDLE

Ala of sacrum Sacro-iliac joint Iliac crest

Iliac fossa

Sacral promontory Anterior superior iliac spine

Sacrum

Sacrococcygeal joint

Anterior inferior iliac spine

Coccyx Ilium

Acetabulum

Hip bone Pubis

Ischial spine

Ischium

Pubic tubercle Obturator foramen

Subpubic angle

Pubic symphysis

A. Anterior View

Pubic arch

Hip bone

Plane of pelvic inlet

Greater pelvis

Hip bone

Gluteal region

Key Greater (false) pelvis Lesser (true) pelvis

Lesser pelvis Perineal region

B. Coronal Section

5.3

Pelvic outlet

Obturator membrane

Sacrum

C. Anterior View

BONES AND DIVISIONS OF PELVIS

A. Bones of pelvis. The three bones com p osing the pelvis are the pubis, ischium , and ilium . B. and C. Lesser and greater pelvis, schem atic illustrations. The plane of the pelvic inlet (double-headed

arrow in B) sep arates the greater pelvis (p art of the abdom inal cavity) from the lesser pelvis (pelvic cavity).

PELVIC GIRDLE

Pe lvis an d Pe rin e um

391

Body of sacrum

Superior articular process Ala of sacrum

Sacral canal

Sacro-iliac joint Sacral promontory

Iliac crest

Sacrum

Iliac fossa

Coccyx Anterior superior iliac spine Ischial spine Anterior inferior iliac spine Groove for iliopsoas Iliopubic eminence

Superior ramus of pubis Pecten pubis Pubic tubercle

A. Anterosuperior View Pubic symphysis

Internal lip of iliac crest Vertical plane

Ala Ilium

Iliac crest Body

Ala of ilium ASIS

Acetabulum

Iliac fossa

Anterior inferior iliac spine

Posterior superior iliac spine

Arcuate line

Posterior inferior iliac spine

Iliopubic eminence Superior ramus of pubis

Body of ischium

Pubic crest

Ischium

Tuberosity of ilium Sacropelvic Auricular surface surface

Greater sciatic notch Ischial spine Lesser sciatic notch

Body of pubis

Ischial tuberosity Triradiate cartilage

B. Lateral View

Inferior ramus of pubis*

C. Medial Aspect

PELVIS, ANATOMICAL POSITION A. Pelvic g ird le. B. Placem en t of hip b one in anatom ical p osition . In the anatom ical p osition, (1) the anterior sup erior iliac sp ine (ASIS) and the an terior asp ect of the p ub is lie in th e sam e vertical

Obturator foramen

Ischial ramus* *Ischiopubic ramus

5.4 p lane and (2) the sacrum is located sup eriorly, the coccyx p osteriorly, and the p ub ic sym p hysis antero-inferiorly. C. Features of hip b on e.

Pe lvis an d Pe rin e um

392

PELVIC GIRDLE

Hip bone

Sacrum

Acetabulum Superior ramus of pubis

Obturator foramen

Pubic arch Ischiopubic ramus

A. Antero-inferior View

Sacro-iliac joint Sacral canal Iliac crest

Sacrum

C. Subpubic Angle

Ala

"V" shaped

Body

Anterior superior iliac spine (ASIS)

Coccyx

Anterior inferior iliac spine Iliopubic eminence

Groove for iliopsoas Superior ramus of pubis

Pecten pubis Pubic tubercle

Pubic symphysis

B. Anterosuperior View

5.5

MALE PELVIC GIRDLE

TABLE 5.1

DIFFERENCES BETWEEN MALE AND FEMALE PELVES

Bony Pelvis

Ma le

Fema le

General structure

Thicker and heavier

Thinner and lighter

Greater pelvis (pelvis major)

Deeper

Shallower

Lesser pelvis (pelvis minor)

Narrower and deeper, tapering

Wider and shallower, cylindrical

Pelvic inlet (superior pelvic aperture)

Heart shaped, narrower

More oval or rounded, wider

Sacrum/coccyx

More curved

Less curved

Pe lvis an d Pe rin e um

PELVIC GIRDLE

393

Acetabulum Inferior Ischiopubic ramus of pubis ramus Ischial ramus

Obturator foramen Pubic arch

A. Antero-inferior View

Sacro-iliac joint

C. Subpubic Angle "U" shaped

Anterior border of ala Promontory of sacrum Arcuate line of ilium

Ischial spine Pecten pubis Pubic tubercle Pubic symphysis

Pubic crest

B. Anterosuperior View

5.6

FEMALE PELVIC GIRDLE TABLE 5.1

DIFFERENCES BETWEEN MALE AND FEMALE PELVES ( cont inued )

Bony Pelvis

Ma le

Fema le

Pelvic outlet (inferior pelvic aperture)

Comparatively small

Comparatively large

Pubic arch and subpubic angle

Narrower

Wider

Obturator foramen

Round

Oval

Acetabulum

Large

Small

394

Pe lvis an d Pe rin e um

PELVIC GIRDLE

ASIS

ASIS

A

Pelvic inlet

O

O PA

A. Anteroposterior Radiograph, Male Pelvis

ASIS

ASIS

A

Pelvic inlet

O

O PA

B. Anteroposterior Radiograph, Female Pelvis

5.7

RADIOGRAPHS OF PELVIS

A. Male. B. Fem ale. Som e of the m ain differences of m ale and fem ale pelves are listed in Table 5.1. The radiographs highlight

som e of these differences. A, acetabulum ; ASIS, anterior sup erior iliac spine; O, obturator foram en; PA, p ubic arch.

LIGAMENTS OF PELVIC GIRDLE

Transverse process of L5 vertebra

Pe lvis an d Pe rin e um

395

Anterior longitudinal ligament

Iliac crest Iliolumbar ligament Iliac fossa Anterior sacro-iliac ligament Anterior superior iliac spine

Anterior sacral foramina

Greater sciatic foramen

Anterior inferior iliac spine

Sacrotuberous ligament Sacrospinous ligament

Pelvic brim (linea terminalis) Iliofemoral ligament

Head of femur

Pubofemoral ligament Inguinal ligament

Pubic tubercle

Femur Pubic symphysis Obturator membrane

Anterior sacrococcygeal ligament

A. Anterior View

Supraspinous ligament

Iliolumbar ligament

Posterior sacro-iliac ligament Posterior superior iliac spine Posterior sacral foramen Posterior sacrococcygeal ligaments

Greater sciatic foramen

Ischiofemoral ligament

Sacrospinous ligament Lesser sciatic foramen

Sacrotuberous ligament

Femur Ischial tuberosity

B. Posterior View

PELVIS AND PELVIC LIGAMENTS

5.8

Pe lvis an d Pe rin e um

396

FLOOR AND WALLS OF PELVIS

Internal iliac artery Sacrum (S1 segment) Lumbosacral trunk (anterior rami L4 and L5)

Ureter S1

Anterior ramus S1

External iliac artery

Anterior ramus S2

S2

External iliac vein

Piriformis S3

Obturator nerve

Anterior ramus S3 Coccygeus

S4 S5

Inferior rectal (anal) nerve Inferior rectal artery

Lacunar ligament

L4

Coccyx

Pectineal ligament L5

Obturator internus

Perineal nerve

Pubic symphysis

Perineal artery

Pubococcygeus

S1

Dorsal nerve and artery of penis

Compressor urethrae External urethral sphincter surrounding urethra

A

Hip bone

S2 S3

Ischial spine Sacrum (S1 segment) O

Sacral canal

Obturator fascia

S4 segment

P

Perineal membrane

Obturator nerve

Greater sciatic foramen

S1

Sacrotuberous ligament

Gluteus medius

S2

Gluteus maximus

S3

Psoas fascia

Sacrotuberous ligament

S4

External iliac artery

Greater sciatic foramen

External iliac vein

S5 segment Sacrospinous ligament Coccyx

Lesser sciatic foramen

C Obturator foramen

Key O Direction of obturator internus P Direction of piriformis

Medial Views

Sacrospinous ligament Ischial spine

Ischium Obturator canal Pubis Pubic symphysis Obturator membrane

Tip of coccyx Sacrotuberous ligament Lesser sciatic foramen Gluteus maximus

Inferior pubic ligament

B

5.9

Lesser sciatic notch

Ischial tuberosity

OBTURATOR INTERNUS AND PIRIFORMIS

• On the lateral pelvic wall, the obturator foram en is closed by the obturator m em brane except for the obturator canal; the obturator internus m uscle attaches to the obturator m em brane and surrounding bone and exits the lesser pelvis through the lesser sciatic foram en; obturator fascia lies on the m edial surface of the m uscle.

• Piriform is lies on the posterolateral pelvic wall and leaves the lesser pelvis through the greater sciatic foram en.

Pe lvis an d Pe rin e um

FLOOR AND WALLS OF PELVIS

397

Muscles of floor of pelvis:

Ureter

S1

External iliac artery

Levator ani (LA) = Pubococcygeus (PC) + Iliococcygeus (IC) (LA= PC + IC)

S1 S2 Anterior rami S3

External iliac vein Obturator nerve

Pelvic diaphragm (PD) = Levator ani (LA) + Coccygeus (C) (PD = LA+ C)

Lumbosacral trunk (L4,5)

Internal iliac artery

S2

Ductus deferens

Piriformis

S3

Site of deep inguinal ring

Pubococcygeus (PC ) = Puborectalis (PR) + Pubovaginalis (PV) (PC = PR + PV )

Ischial spine

S4

Inferior epigastric artery and vein

Pubococcygeus (PC ) = Puborectalis (PR) + Puboprostaticus (PP) (Levator prostatae) (PC = PR + PP )

S5

Obturator artery and vein

Coccygeus (C)

Obturator fascia covering obturator internus

Coccyx

Tendinous arch of levator ani

Iliococcygeus (IC)

Pubic symphysis Urogenital hiatus (edge)

A. Medial View

Pubococcygeus (PC)

Rectum

Puborectalis

Sacrum Greater sciatic foramen

Coccygeus (C)

Anococcygeal body

Puborectalis

Tendinous arch of levator ani

Iliococcygeus (IC) Pubococcygeus (PC) Pubovaginalis (PV) ( ) Puboprostaticus (PP) ( )

Rectum Perineal body

Obturator fascia covering obturator internus Pubic symphysis

Urogenital hiatus

B. Anterosuperior View

TABLE 5.2

MUSCLES OF PELVIC DIAPHRAGM

5.10

A. The pelvic oor is form ed by the funnel- or bowl-shaped pelvic diaphragm . The funnel shape can be seen in a m edial view of a m edian section. B. The bowl shape from a sup erior view.

MUSCLES OF PELVIC WALLS AND FLOOR

Bounda ry

Muscle

Proxima l Atta chment

Lateral wall

Obturator internus

Pelvic surfaces of ilium and ischium, obturator membrane

Posterolateral wall

Piriformis

Pelvic surface of S2–S4 segments, superior margin of greater sciatic notch, sacrotuberous ligament

Floor

Levator ani (pubococcygeus, puborectalis, and iliococcygeus) Coccygeus (ischiococcygeus)

Dista l Atta chment

Innerva tion

Ma in Action

Nerve to obturator internus (L5, S1, S2)

Rotates hip joint laterally; assists in holding head of femur in acetabulum

Greater trochanter of femur

Anterior rami of S1 and S2

Rotates hip joint laterally; abducts hip joint; assists in holding head of femur in acetabulum

Body of pubis, tendinous arch of obturator fascia, ischial spine

Perineal body, coccyx, anococcygeal ligament, walls of prostate or vagina, rectum, and anal canal

Nerve to levator ani (branches of S4), inferior anal (rectal) nerve, and coccygeal plexus

Forms most of pelvic diaphragm that helps support pelvic viscera and resists increases in intra-abdominal pressure

Ischial spine

Inferior end of sacrum and coccyx

Branches of S4 and S5 spinal nerves

Forms small part of pelvic diaphragm that supports pelvic viscera; exes sacrococcygeal joints

398

Pe lvis an d Pe rin e um

FLOOR AND WALLS OF PELVIS

Sacro-iliac joint

Sacrum

Ilium S3 S4

Anterior rami Piriformis

Inferior gluteal artery

Median sacral artery Coccygeus

Nerves to coccygeus and levator ani Tendinous arch of levator ani

Obturator vein Obturator artery

Obturator fascia covering obturator internus

Obturator nerve

Puborectalis Iliococcygeus Tendinous arch of pelvic fascia

Suture retracting rectum

Pubococcygeus Rectum Urethra Puboprostaticus (anterior part pubococcygeus)

A. Anterosuperior View

Anterior border of levator ani

Pubic symphysis

Urogenital hiatus closed by perineal membrane

Sacro-iliac joint Sacrum

Ilium

Anterior sacrococcygeal ligament

Piriformis

Coccygeus

Tendinous arch of levator ani Obturator internus

Levator ani: Iliococcygeus

Rectum

Pubococcygeus Puborectalis

Deep transverse perineal muscle

Obturator canal

Urethra Compressor urethrae

Perineal membrane Deep dorsal vein of penis Pubis

B. Superior View

5.11

FLOOR AND WALLS OF MALE PELVIS, PELVIC DIAPHRAGM

External urethral sphincter Pubic symphysis

Pe lvis an d Pe rin e um

FLOOR AND WALLS OF PELVIS

399

Vertebral body of L5 Sacral promontory (L5/S1 intervertebral disc) Psoas Ala of sacrum L4 L5

Piriformis

S1 Lumbosacral trunk

S2

Sacrum

S3 S4

Nerve to levator ani

Anterior rami of sacral plexus

Coccygeus

Obturator nerve

Ischial spine Pubococcygeus

Rectum

Obturator canal Femoral artery

Pubovaginalis Femoral ring

Femoral vein

Lacunar ligament Pecten pubis Vagina

A. Anterior View

Urinary bladder

Pubic symphysis

Sacro-iliac joint Ilium

Sacrum Anterior sacrococcygeal ligament

Piriformis

Coccygeus

Tendinous arch of levator ani

Levator ani: Iliococcygeus

Obturator internus

Pubococcygeus

Rectum

Puborectalis

Deep transverse perineal muscle Vagina

Obturator canal

Urethra

Urethrovaginal sphincter

Perineal membrane Deep dorsal vein of clitoris

B. Superior View

FLOOR AND WALLS OF FEMALE PELVIS

Pubis

Compressor urethrae External urethral sphincter Pubic symphysis

5.12

Pe lvis an d Pe rin e um

400

SACRAL AND COCCYGEAL PLEXUSES

Key

Psoas muscle

LA Levator ani P Piriformis

Common iliac a.

Internal iliac a. Iliolumbar a. External iliac a.

Superior gluteal a.

L5

Internal iliac v.

Rami communicantes

L4 Obturator n.

Sympathetic trunk

Lumbosacral trunk

Lateral sacral a.

S1 Superior gluteal n.

Sympathetic ganglion

P Internal pudendal a.

S2

Nn. to piriformis

P Obturator a. S3

Median sacral a.

N. to quadratus femoris

Anterior ramus (S4)

P

Sciatic n. N. to obturator internus

N. to coccygeus

Inferior gluteal a.

Coccygeus

Pudendal n.

Anterior ramus (S5)

LA

Pubic bone Pelvic splanchnic nn.

Nn. to levator ani A. Medial View, Right Half of Hemisected Pelvis

5.13

Coccygeal plexus LA

Anococcygeal nn.

SACRAL AND COCCYGEAL NERVE PLEXUSES

A. Dissection. • The sym pathetic trunk or its ganglia send ram i com m unicantes to each sacral and coccygeal nerve. • The anterior ram us from L4 joins that of L5 to form the lum bosacral trunk.

• The sciatic nerve arises from anterior ram i of L4, L5, S1, S2, and S3; the p udendal nerve from S2, S3, and S4; and the coccygeal plexus from S4, S5, and coccygeal segm ents.

SACRAL AND COCCYGEAL PLEXUSES

Pe lvis an d Pe rin e um

401

L4 Lumbosacral trunk

Key

L5

Anterior division Posterior division

S1 Sacral plexus S2

*

Superior gluteal nerve

S3

Inferior gluteal nerve

*Pelvic splanchnic nerves

* Nerve to piriformis

S4

*

S5

Coccygeal plexus

Co1

Anococcygeal nerves Common fibular nerve Sciatic nerve Tibial nerve

B. Anterior View

Nerves to levator ani and coccygeus Pudendal nerve Perforating cutaneous nerves Obturator Posterior cutaneous nerve of thigh internus Nerve to Superior gemellus Quadratus Nerve to femoris Inferior gemellus

SACRAL AND COCCYGEAL NERVE PLEXUSES (continued )

5.13

B. Branches of anterior and posterior divisions of sacral and coccygeal plexuses.

TABLE 5.3

NERVES OF SACRAL AND COCCYGEAL PLEXUSES

Nerve

Origin

Distribution

Sciatic: 1. Common bular 2. Tibial

L4, L5, S1, S2

Articular branches to hip joint and muscular branches to exors of knee joint in thigh and all muscles in leg and foot

3. Superior gluteal

L4, L5, S1

Gluteus medius and gluteus minimus muscles

4. Nerve to quadratus femoris and inferior gemellus

L4, L5, S1

Quadratus femoris and inferior gemellus muscles

5. Inferior gluteal

L5, S1, S2

Gluteus maximus muscle

6. Nerve to obturator internus and superior gemellus

L5, S1, S2

Obturator internus and superior gemellus muscles

7. Nerve to piriformis

S1, S2

Piriformis muscle

8. Posterior cutaneous nerve of thigh

S1, S2, S3

Cutaneous branches to buttock and uppermost medial and posterior surfaces of thigh

9. Perforating cutaneous

S2, S3

Cutaneous branches to medial part of buttock

10. Pudendal

S2, S3, S4

Structures in perineum, sensory to genitalia, muscular branches to perineal muscles, external urethral sphincter, and external anal sphincter

11. Pelvic splanchnic

S2, S3, S4

Pelvic viscera via inferior hypogastric and pelvic plexuses

12. Nerves to levator ani and coccygeus

S3, S4

Levator ani and coccygeus muscles

13. Anococcygeal nerve

S4, S5, Co1

Penetrate coccygeal attachments of sacrospinous/sacrotuberous ligaments to supply overlying skin

L4, L5, S1, S2, S3

Pe lvis an d Pe rin e um

402

PERITONEAL REFLECTIONS IN PELVIS

Sacrum (S1 segment) Peritoneum

Appendix

Suspensory ligament of ovary

Inferior epigastric artery in lateral umbilical fold

Broad ligament of uterus

Medial umbilical ligament in medial umbilical fold

Uterine tube Ovary

Round ligament of uterus

Cervix

Uterus

Recto-uterine fold

Vesico-uterine pouch

Recto-uterine pouch

Urinary bladder

Posterior fornix Supravesical fossa

Coccyx

Pubic symphysis

Anococcygeal body

Retropubic space Levator ani

Retropubic fat Urethra

Vagina

Inferior pubic ligament

Ampulla of rectum

Labium minus

Anal canal Labium majus

A

8

Medial Views of Right Half of Hemisected Female Pelvis

(B) Peritoneal reflections in females Peritoneum passes: 1. From the anterior abdominal wall 2. Superior to the pubic bone, forming supravesical fossa 3. On the superior surface of the urinary bladder 4. From the bladder to mid-uterus, forming the vesico-uterine pouch 5. On the fundus and body of the uterus, and posterior fornix of the vagina 6. Between the rectum and uterus, forming the recto-uterine pouch 7. On the anterior and lateral sides of the rectum 8. Posteriorly to become the sigmoid mesocolon

5

6

8

7

4

1 3 2

Rectum

5.14

PERITONEUM COVERING FEMALE PELVIC ORGANS

A. Organs in situ with peritoneal re ections. B. Schematic illustration of peritoneal re ections. The level of the supravesical fossa changes with lling and emptying of bladder.

Retropubic space Urinary bladder

B

Uterus Vagina

PERITONEAL REFLECTIONS IN PELVIS

Pe lvis an d Pe rin e um

403

Sacrum (S1 segment) Peritoneal cavity Rectus abdominis Urinary bladder Rectovesical pouch

Peritoneum

Internal urethral sphincter

Supravesical fossa Retropubic space

Rectovesical fascia Fat pad

Coccyx (Co1 segment)

Pubic symphysis Prostate

Prostatic urethra Levator ani

Puboprostatic ligament

Rectum Puborectalis Deep transverse perineal External urethral sphincter (sphincter urethrae)

Intermediate (membranous) urethra Intrabulbar fossa

Internal anal sphincter

Spongy urethra

Anal columns

A

Perineal membrane Bulbospongiosus Bulb of penis

Medial Views Testis

Subcutaneous Parts of external anal Superficial sphincter Deep

8

8 6 1

7

5 3

4

2

Rectum

Urinary bladder

(B) Peritoneal reflections in males Peritoneum passes: 1. From the anterior abdominal wall 2. Onto apex of bladder, forming supravesical fossa 3. On the superior surface of the urinary bladder 4. 2 cm inferiorly on the posterior surface of the urinary bladder 5. On the superior ends of the seminal glands 6. Posteriorly to line the rectovesical pouch 7. To cover the rectum 8. Posteriorly to become the sigmoid mesocolon

Seminal gland

Puboprostatic ligament

PERITONEUM COVERING MALE PELVIC ORGANS B Prostate

5.15

A. Organs in situ. The urinary bladder is distended and displaced posteriorly in this specim en, not anteriorly as is usual, forming a broad and deep supravesical fossa even when the bladder is full. B. Peritoneum covering male pelvic organs. Typically, the location of supravesical fossa changes with lling and emptying of bladder.

Pe lvis an d Pe rin e um

404

RECTUM AND ANAL CANAL

Sacrum (S2 segment)

S2 Anterior rami S3 Urinary bladder Coccygeus Internal urethral sphincter

Pelvic splanchnic nerves Fibers to rectum

Pubic symphysis

Nerve to levator ani Ductus deferens

Prostate

Coccyx Puboprostatic ligament

Seminal gland Pubococcygeus (cut edge)

External urethral sphincter

Puborectalis Deep part Superficial part

Perineal membrane

Subcutaneous

A. Medial View

Superficial Deep Testis

Bulbospongiosus

External anal sphincter

Parts of external anal sphincter

Perineal body

Hip bone

5.16

Pubic symphysis

ANAL SPHINCTERS AND ANAL CANAL

A. Levator ani, in right half of hem isected pelvis. • The subcutaneous bers of the external anal sphincter and overlying skin are re ected with forceps. The p ubococcygeus m uscle is cut to reveal the anal canal, to which it is, in p art, attached. B. Pub orectalis. • The innerm ost part of the levator ani/ pubococcygeus m uscle, the p uborectalis, form s a U-shap ed m uscular “sling” around the anorectal junction, which m aintains the anorectal (p erineal) exure.

Puborectalis (forming puborectal sling)

80˚ anorectal angle at anorectal junction Anal canal

B. Medial View

RECTUM AND ANAL CANAL

Pe lvis an d Pe rin e um

405

Circular muscle coat Longitudinal muscle coat

Levator ani Puborectalis

Regions of Anal Canal Columnar zone Anal pecten Cutaneous zone

Deep*

Anorectal junction

Superficial

Parts of external anal sphincter

Subcutaneous Internal anal sphincter Pectinate line

Anocutaneous line

C. Medial View Fibro-elastic septa

* Blended with puborectalis

Peri-anal skin

Intestinal mucosa

Anal column Anal sinus Anal valve

Internal rectal venous plexus

Anal pecten

Pectinate line Internal anal sphincter

Skin

External anal sphincter

D. Medial View

ANAL SPHINCTERS AND ANAL CANAL (continued ) C. External and internal anal sp hincters. • The internal anal sphincter is a thickening of the inner, circular m uscular coat of the anal canal. • The external anal sphincter has three often indistinct continuous zones: deep , super cial, and subcutaneous; the deep p art interm ingles with the puborectalis m uscle p osteriorly. • The longitudinal m uscle layer of the rectum separates the internal and external anal sp hincters and term inates in the subcutaneous tissue and skin around the anus. D. Features of the anal canal. • The anal colum ns are 5 to 10 vertical folds of m ucosa separated by anal sinuses and valves; they contain p ortions of the rectal venous plexus.

5.16 • The pecten is a sm ooth area of hairless strati ed epithelium that lies between the anal valves superiorly and the inferior border of the internal anal sphincter inferiorly. • The pectinate line is an irregular line at the base of the anal valves where the intestinal m ucosa is continuous with the pecten; this indicates the junction of the superior part of the anal canal (derived from em bryonic hindgut) and the inferior part of the anal canal (derived from the anal pit [proctodeum ]). Innervation is visceral proxim al to the line and som atic distally; lym phatic drainage is to the pararectal nodes proxim ally and to the super cial inguinal nodes distally.

Pe lvis an d Pe rin e um

406

Right external iliac artery

Right and left branches of superior rectal artery

RECTUM AND ANAL CANAL

Sympathetic trunk

Root of sigmoid mesocolon Lateral sacral artery

Left internal iliac artery

Left ureter

Peritoneum Left external iliac artery Left femoral nerve

Right femoral nerve

Lumbosacral trunk (L4–L5)

Psoas

Umbilical artery Anterior ramus S1

Iliacus

Superior gluteal artery Anterior ramus S2

Right ureter

Obturator nerve Obturator artery

Piriformis

Sciatic nerve

Inferior gluteal artery

Obturator internus

Anterior ramus S3 Anterior ramus S4 Coccygeus Iliococcygeus

Obturator fascia covering obturator internus

Sacrotuberous ligament

Tendinous arch of levator ani Pudendal nerve in pudendal Internal pudendal artery canal

Rectum Pubococcygeus Anterior View

Puborectalis External anal sphincter

5.17

Inferior rectal artery Uterine artery Middle rectal artery

RECTUM, ANAL CANAL, AND NEUROVASCULAR STRUCTURES OF POSTERIOR PELVIS

The p elvis is coronally bisected anterior to the rectum and anal canal. The superior gluteal artery often passes posteriorly between

the anterior ram i of L5 and S1, and the inferior gluteal artery between S2 and S3.

RECTUM AND ANAL CANAL Superior transverse rectal fold Superior rectal vein

Superior rectal artery Middle transverse rectal fold Middle rectal artery

Middle re cta l ve in

Obturator internus Levator ani

Inferior transverse rectal fold

Internal pudendal artery

Internal pudendal vein

Inferior rectal artery

Inferior rectal vein

Ischio-anal fossa

Rectal venous plexus

External anal sphincter

A. Coronal Section Inferior mesenteric artery Abdominal aorta

Left common iliac artery Left internal iliac artery

A B

Left external iliac artery Left femoral artery

C

B. Anterior View Veins: To portal venous system Key for B A Superior half of rectum B Inferior half of rectum C Anal canal Lumbar Inferior mesenteric Common iliac Internal iliac External iliac Superficial inguinal Deep inguinal Sacral Direction of flow of lymph

Lymphatics: To internal iliac lymph nodes

Pectinate line

To superficial inguinal lymph nodes To caval venous system

C. Coronal Section

Pe lvis an d Pe rin e um

407

Internal iliac vein Middle rectal vein

Rectum

Internal pudendal vein

Internal hemorrhoid

Internal rectal plexus

External anal sphincter

Inferior rectal vein External rectal plexus

External hemorrhoid

D. Anterior Views of Coronal Section

VASCULATURE AND LYMPHATIC DRAINAGE OF RECTUM

5.18

A. Arterial and venous drainage. B. Lymphatic drainage. C. Venous and lymphatic drainage superior and inferior to the pectinate line. D. Hem orrhoids. Intern al h em orrh oid s (piles) are prolapses of rectal mucosa containing the normally dilated veins of the internal rectal venous plexus. Internal hemorrhoids are thought to result from a breakdown of the muscularis mucosae, a smooth muscle layer deep to the mucosa. Internal hemorrhoids that prolapse through the anal canal are often compressed by the contracted sphincters, impeding blood ow. As a result, they tend to strangulate and ulcerate. Because of the presence of abundant arteriovenous anastomoses, bleeding from internal hemorrhoids is characteristically bright red. The current practice is to treat only prolapsed, ulcerated internal hemorrhoids. Ext e rn al h e m o rrh o id s are throm boses (blood clots) in the veins of the external rectal venous p lexus and are covered by skin. Predisp osing factors for hem orrhoids include p regnancy, chronic constipation, and any disorder that im pedes venous return including increased intra-abdom inal pressure. The superior rectal vein drains into the inferior m esenteric vein, whereas the m iddle and inferior rectal veins drain through the system ic system into the inferior vena cava. Any abnorm al increase in pressure in the valveless portal system or veins of the trunk m ay cause enlargem ent of the superior rectal veins, resulting in an increase in blood ow or stasis in the internal rectal venous plexus. In p o rt al h yp e rt e n sio n that occurs in relation to h e p at ic cirrh o sis, the portacaval anastom osis (e.g., esop hageal) m ay becom e varicose and rupture. Note that the veins of the rectal plexuses norm ally appear varicose (dilated and tortuous), even in newborns, and that internal hem orrhoids occur m ost com m only in the absence of portal hypertension. Regarding pain from and the treatm ent of hem orrhoid s, note that the anal canal superior to the pectinate line is visceral; thus, it is innervated by visceral afferent pain bers, so that an incision or needle insertion into this region is painless. Internal hem orrhoids are not painful and can be treated without anesthesia. Inferior to the pectinate line, the anal canal is som atic, supplied by the inferior anal (rectal) nerves containing som atic sensory bers. Therefore, it is sensitive to painful stim uli (e.g., to the prick of a hypoderm ic needle). External hem orrhoids can be painful but often resolve in a few days.

408

Pe lvis an d Pe rin e um

RECTUM AND ANAL CANAL

Upper lumbar sympathetic trunk T12 L1 L2

L3 L4

Lumbar splanchnic nerves

Spinal (sensory) ganglia Pelvic splanchnic nerves

L5 S1

S2

Pelvic plexus

S3 Prevertebral (sympathetic) ganglia

S4

Aortic plexus

Sacral plexus Superior rectal nerves

Superior hypogastric plexus

Pudendal nerve

Inferior hypogastric plexuses Pelvic plexus

Innervation Visceral afferents running with parasympathetic fibers Presynaptic Postsynaptic

Parasympathetic

Presynaptic Postsynaptic

Sympathetic Inferior anal (rectal) nerve

Somatic motor Somatic afferrent Anal sphincter

5.19

External Internal

INNERVATION OF RECTUM AND ANAL CANAL

The lum bar and p elvic sp inal nerves and hypogastric plexuses have been retracted laterally for clarity.

RECTUM AND ANAL CANAL

Aorta

Pe lvis an d Pe rin e um

409

Inferior mesenteric artery

Inferior vena cava

Aortic plexus

Sigmoid colon

Left common iliac artery Superior hypogastric plexus Sigmoid mesocolon Ureter Internal iliac artery Genitofemoral nerve Psoas External iliac artery Testicular veins Testicular artery Testicular vessels in sheath Peritoneum (cut edge) External iliac vein Ductus deferens Inferior epigastric artery

Pararectal fossa Sacrogenital fold Rectum (ampulla) Rectovesical pouch Paravesical fossa Urinary bladder (deep to peritoneum)

Anterosuperior View

RECTUM IN SITU • The sigm oid colon begins at the left pelvic brim and becom es the rectum anterior to the third sacral segm ent in the m idline. • The superior hypogastric plexus lies inferior to the bifurcation of the aorta and anterior to the left com m on iliac vein. • The ureter adheres to the external aspect of the peritoneum , crosses the external iliac vessels, and descends anterior to the

5.20 internal iliac artery. The ductus deferens and its artery also adhere to the peritoneum , cross the external iliac vessels, and then hook around the inferior epigastric artery to join the other com p onents of the sperm atic cord . • The genitofem oral nerve lies on the psoas.

Pe lvis an d Pe rin e um

410

ORGANS OF MALE PELVIS

Median umbilical fold and ligament (urachus) Peritoneum

Extraperitoneal fascia (fatty tissue)

Medial umbilical fold

Medial umbilical ligament (obliterated umbilical artery)

Femoral nerve Iliacus Psoas External iliac artery

Psoas fascia Inferior epigastric vessels

External iliac vein Rectus abdominis

Ureter Vessels to urogenital organs

Hypogastric sheath

Ductus deferens Urinary bladder

Seminal gland

Prostate (enlarged) Retropubic space

Tendinous arch of levator ani

Paravesical space

Obturator internus

Pudendal nerve

Levator ani

Internal pudendal artery

Bulbo-urethral glands in deep perineal compartment

Levator ani

Perineal membrane

Ischio-anal fossa

Sciatic nerve

Artery to bulb, piercing perineal membrane

Perineal branches of posterior cutaneous nerve of thigh

Deep perineal nerve Bulbospongiosus

A. Posterior View

5.21

POSTERIOR APPROACH TO ANTERIOR PELVIC AND PERINEAL STRUCTURES AND SPACES

A. Dissection. The rectovesical septum and all pelvic and perineal structures posterior to it have been rem oved. B. Schem atic coronal section through the anterior p elvis (p lane of urinary bladder and prostate) dem onstrating pelvic fascia. • The inferior ep igastric artery and accom panying veins enter the rectus sheath, covered posteriorly with peritoneum to form the lateral um bilical fold. The m edial um bilical fold is form ed by peritoneum overlying the m edial um bilical ligam ent (obliterated um bilical artery), and the m edian um bilical fold is form ed by the m edian um bilical ligam ent (urachus). • The pelvic genito-urinary organs are sub peritoneal. Near the bladder, the ureter accom panies a “leash” of internal iliac vessels and derivatives within the hyp ogastric sheath, a bro-areolar structure.

Key occupied by * = spaces fatty endopelvic fascia

Endo-abdominal fascia Parietal abdominal fascia Iliopsoas

Iliacus Psoas

Firm attachment to pelvic brim

Peritoneum

Parietal pelvic fascia Tendinous arch of levator ani

*Retropubic space with endopelvic

Visceral pelvic fascia

Bladder

fascia, vessels and nerves Obturator fascia Obturator internus

Prostate

Tendinous arch of pelvic fascia

Pudendal canal Parietal perineal fascia

*Ischio-anal (ischiorectal) fossa B. Coronal Section

Urethra Levator ani with superior and inferior parietal fascia

Pe lvis an d Pe rin e um

ORGANS OF MALE PELVIS

411

Ureter

Ductus deferens

Urinary bladder Ampulla of ductus deferens Pubic symphysis

Seminal gland

Intramural part

Urethra

Ejaculatory duct

Prostatic Prostate

Intermediate part (membranous) Spongy

Perineal membrane Corpus spongiosum

Bulb of penis

A. Median Section Parts of Male Urethra in B

Ductus deferens Inguinal canal (schematic)

Ureter (pelvic part)

Urinary bladder

Ureter (intramural part)

Intramural (preprostatic) Prostatic Intermediate (membranous) Spongy (penile)

Pubic symphysis Seminal gland

Prostate

Cut and ligated ductus deferens

Ejaculatory duct Bulbo-urethral gland Bulbo-urethral duct Epididymis Efferent ductules Glans penis

B. Schematic Median Section

Deferentectomy (vasectomy)

Testis Ductus deferens

URINARY BLADDER, PROSTATE, SEMINAL GLANDS, AND DUCTUS DEFERENS A. Dissection. The ejaculatory duct ( 2 cm in length) is form ed by the union of the d uctus deferens and duct of the sem inal g land; it passes anteriorly and inferiorly through the substance of the prostate to enter the prostatic urethra. B. Overview of urogenital system , schem atic illustration. The com m on m ethod of sterilizing

5.22

m ales is a d e fe re n t e ct o m y, pop ularly called vase ct o m y. During this procedure, part of the ductus deferens is ligated and/ or excised through an incision in the superior part of the scrotum . Hence, the subsequent ejaculated uid contains no sp erm s.

Pe lvis an d Pe rin e um

412

ORGANS OF MALE PELVIS Ampulla of ductus deferens Seminal gland Ductus deferens

Peritoneum Urinary bladder

Ureter

Ureter

Lobules of prostate Isthmus of prostate Inferolateral lobule Prostatic urethra Anteromedial lobule Lateral ligament of bladder

Seminal colliculus Ejaculatory ducts

Visceral pelvic fascia

Superomedial lobule Inferoposterior lobule

C. Transverse Section

Level of section

Ejaculatory duct

Furrow in posterior surface Prostatic rectovesical septum Prostate

Intermediate (membranous) urethra

Anterior View

Ductus deferens

Ductus deferens

Ampulla of ductus deferens Seminal gland

Lateral ligament of bladder Seminal gland Ampulla of ductus deferens

Retropubic space Prostatic utricle Prostate

Ejaculatory duct

D. Unraveled Seminal Gland (Vesicle)

5.22

Ejaculatory ducts Prostatic ductules Levator ani and superior and inferior fascia of pelvic diaphragm

External urethral sphincter Intermediate (membranous) urethra

E. Posterior View

URINARY BLADDER, PROSTATE, SEMINAL GLANDS, AND DUCTUS DEFERENS (continued )

C. Bladder, ductus deferens, sem inal gland s (vesicles), and lobules of prostate. The left sem inal gland and am p ulla of the ductus deferens are dissected and opened; part of the prostate is cut away to exp ose the ejaculatory duct. D. Sem inal gland unraveled. The gland is a tortuous tube with num erous dilatations. The am pulla

of the ductus deferens has sim ilar dilatations. E. Prostate, dissected posteriorly. The ejaculatory duct enters the p rostatic urethra on the sem inal colliculus. The prostatic utricle lies between the ends of the two ejaculatory ducts. The prostatic ductules m ostly open onto the prostatic sinus.

ORGANS OF MALE PELVIS

Pe lvis an d Pe rin e um

413

Peritoneum

Ureter

Ureteric orifice

Ductus deferens Ureteric orifice Interureteric fold

Urinary bladder

Detrusor muscle Inferolateral surface of bladder

Trigone of urinary bladder Uvula of urinary bladder Internal urethral orifice

Uvula

Vesical Venous plexus

Prostatic sinus

Internal urethral orifice

Prostatic

Seminal colliculus

Prostatic utricle Cut surface of prostate

Internal urethral sphincter Seminal colliculus Prostatic sinus (features openings of prostatic ductules) Prostatic utricle

Urethral crest Prostate Intermediate urethra Bulb of penis

Openings of ejaculatory ducts

A. Anterior View

Cut surface of prostate Urethral crest

Intermediate (membranous) urethra

B. Anterior View

INTERIOR OF MALE URINARY BLADDER AND PROSTATIC URETHRA A. Dissection. The anterior walls of the bladder, prostate, and urethra were cut away. B. Features of the p rostatic urethra. • The m ucous m em brane is sm ooth over the trigone of the urinary bladder (triangular region dem arcated by ureteric and internal urethral ori ces) but folded elsewhere, especially when the bladder is em pty. • The opening of the vestigial p rostatic utricle is in the sem inal colliculus on the urethral crest; there is an ori ce of an ejaculatory duct on each side of the prostatic utricle. The prostatic fascia encloses the p rostatic venous plexus. The prostate is of considerable m edical interest because enlargem ent or b e n ig n h yp e rt ro p h y o f t h e p rost at e (BHP) is com m on

5.23

after m iddle age, affecting virtually every m ale who lives long enough. An enlarged prostate projects into the urinary b ladder and im pedes urination by distorting the prostatic urethra. The m iddle lobule usually enlarges the m ost and obstructs the internal urethral ori ce. The m ore the person strains, the m ore the valvelike prostatic m ass occludes the urethra. BHP is a com m on cause of urethral obstruction, leading to n o ct uria (needing to void d uring the night), d ysuria (dif culty and/ or pain during urination), and urg e n cy (sudden desire to void). BHP also increases the risk of bladder infections (cyst it is) as well as kidney dam age.

Pe lvis an d Pe rin e um

414

ORGANS OF MALE PELVIS

Rectus abdominis Spermatic cord

FV FA

Nerve (FN) Artery (FA) Femoral Vein (FV)

Urinary bladder (UB)

Pubis (B)

Head of femur (HF)

B HF

Ductus deferens Seminal gland (SG) Sciatic nerve (SN) Rectum (R)

UB OI

I

Ischium (I)

SN

Superior gemellus

Max

IAF

R

IAF

HF

OI

SG

SG

Obturator internus (OI)

FN

SL

Max

SL Cx

Sacrospinous ligament (SL)

GC

Coccyx (Cx) Gluteus maximus (Max)

Gluteal cleft

Transverse MRI PR

A. Transverse Section

Adductor longus Adductor brevis

Spermatic cord (Sc) Artery (FA) Vein (FV) Nerve (FN)

Pubic symphysis (Sy) Pubis (B) Prostate (P) Urethra Obturator internus (OI) Ischium (I) Rectum (R) Coccyx (Cx) Gluteal cleft (GC)

Sy

B

Femoral

FV FA

B

Pec OE

OI

Pectineus (Pec) Prostatic venous plexus Obturator externus (OE) Puborectalis (PR) Internal pudendal vein PV Internal pudendal artery Pudendal nerve

Sc

I

P

OI

R

PV

I

PR

IAF

IAF

Max

Max GC

Transverse MRI

Ischio-anal fossa (IAF) Gluteus maximus (Max)

Urinary bladder Prostate

B. Transverse Section B A

5.24

MALE PELVIS, TRANSVERSE SECTIONS AND MRI

A. Transverse section and MRI through urinary bladder, sem inal gland, and rectum . B. Transverse section and MRI through prostate and rectum . C. Digital rectal exam ination. The prostate is exam ined for enlargem ent and tum ors (focal m asses or asym m etry) by d ig it al re ct al e xam in at io n . A full bladder offers resistance, holding the gland in place and m aking it m ore readily p alp able. The m alignant p rostate feels hard and often irregular.

Rectum

Anal canal

C. Sagittal Section

Pe lvis an d Pe rin e um

ORGANS OF MALE PELVIS

6

Pubic symphysis (1)

Urinary bladder (6)

Prostatic urethra (2)

Prostate (7)

1

3

Ampulla of ductus deferens (8)

Isthmus (AMZ) of prostate (3)

7

Seminal gland (9)

Intermediate (membranous) urethra (4)

2 13 7 10

8

10

Rectal wall (11) Rectum (12)

9

7

5 14

4

A. Median Section

5 11

Key for US Scan 12 13 14

2

2

3

Ejaculatory duct (10)

External urethral sphincter (5)

415

12

Site of transducer in rectum Concretions surrounding distended and collapsed urethra Calcification in seminal colliculus

Prostatic capsule

Prostatic venous plexus

Longitudinal (Median) US

Anterior muscular zone (AMZ)

AMZ

Prostatic urethra

AMZ

Seminal colliculus Prostatic sinus (receiving openings of prostatic ducts)

PZ

PZ CZ

Peripheral zone of prostate (PZ)

PZ

PZ CZ

Prostatic utricle Ejaculatory ducts Central (internal) zone of prostate (CZ) Anterior wall of rectum

B. Schematic Illustration

Rectum

TRANSRECTAL ULTRASOUND SCANS OF MALE PELVIS A. Longitudinal scan. B. Transverse scan. The probe was inserted into the rectum to scan the anteriorly located prostate. The ducts of the glands in the peripheral zone open into the p rostatic sinuses, whereas the ducts of the glands in the central (internal) zone op en into the prostatic sinuses and onto the sem inal colliculus. Because of the close relationship of the p rostate to the prostatic urethra, obstructions of the urethra m ay be relieved endoscopically. The instrum ent is inserted transurethrally through the external urethral ori ce and spongy urethra into the prostatic urethra. All or part of the prostate, or just the hypertrophied part, is rem oved by

Transverse US

5.25 t ran sure t h ral re se ct io n o f t h e p ro st at e (TURP). In m ore serious cases, the entire prostate is rem oved along with the sem inal glands, ejaculatory ducts, and term inal parts of the deferent ducts (rad ical p ro st at e ct o m y). TURP and im proved operative techniques (laparoscopic or robotic surgery) attem pt to preserve the nerves and blood vessels associated with the capsule of the prostate and adjacent to the sem inal vesicles as they p ass to and from the p enis, increasing the possibility for patients to retain sexual function after surgery as well as restoring norm al urinary control.

Pe lvis an d Pe rin e um

416

VESSELS OF MALE PELVIS

Internal iliac artery

Common iliac artery Ureter

Superior gluteal artery

Testicular artery

Inferior gluteal artery

Testicular veins

Internal pudendal artery

Psoas fascia

Sacrum

External iliac artery External iliac vein Pelvic splanchnic nerves

Superior vesical arteries

Medial umbilical fold Ductus deferens

Inferior vesical artery

Artery to ductus deferens

Middle rectal artery

Umbilical artery (obliterated)

Urinary bladder

Anomalous (accessory) obturator vein and artery

Rectovesical pouch

Obturator nerve

Prostate

Obturator vein Rectum

Peritoneum

A. Medial View Pubic symphysis

External iliac artery External iliac vein

External iliac artery

Nerve Artery Obturator Vein

External iliac vein Inferior epigastric artery

Inferior epigastric artery

Obturator nerve Obturator artery Obturator vein

Pubic branch Pubic branch

Pubic branches Anomalous (accessory) obturator vein and artery Pubic symphysis

B. Medial Views

ANOMALOUS TYPICAL

5.26

PELVIC VESSELS IN SITU; LATERAL PELVIC WALL

A. Dissection of lateral pelvic wall. The ureter crosses the external iliac artery at its origin (com m on iliac bifurcation), and the ductus deferens crosses the external iliac artery at its term ination (deep inguinal ring). In this specim en, an anom alous (accessory) obturator

artery branches from the inferior epigastric artery. B. Typical and anom alous obturator arteries. Surgeons perform ing hernia repairs m ust keep this com m on variation in m ind.

Pe lvis an d Pe rin e um

VESSELS OF MALE PELVIS

Common iliac (1) Iliolumbar Internal iliac (2)

3

1

2

8 Superior vesical

Lateral sacral (7)

External iliac (3) Obturator (4) Deep circumflex iliac (5) Inferior epigastric (6)

7 5

Gluteal: Superior (8) Inferior (9)

6

Inferior vesical

4

Inferior vesical 9 10 11 B

Internal pudendal (10)

Medial umbilical ligament

R

P

Rectal venous plexus

Middle rectal (cut ends) (11)

Superior vesical Urinary bladder (B) Prostate (P)

Vesical venous plexus

Rectum (R) Prostatic branch of inferior vesical artery

A. Median Section

B. Median Section

Prostatic venous plexus Deep dorsal vein of penis

5.27

ARTERIES AND VEINS OF MALE PELVIS A. Arteries. B. Veins. The neurovascular structures of the pelvis lie extraperitoneally. When dissecting from the pelvic cavity toward the p elvic walls,

TABLE 5.4

417

the pelvic arteries are encountered rst, followed by the associated pelvic veins, and then the som atic nerves of the pelvis.

ARTERIES OF MALE PELVIS

Artery

Origin

Course

Distribution

Internal iliac

Common iliac artery

Passes medially over pelvic brim and descends into pelvic cavity; often forms anterior and posterior divisions

Main blood supply to pelvic organs, gluteal muscles, and perineum

Anterior division of internal iliac artery

Internal iliac artery

Passes laterally along lateral wall of pelvis, dividing into visceral, obturator, and internal pudendal arteries

Pelvic viscera, perineum, and muscles of superior medial thigh

Umbilical

Anterior division of internal iliac artery

Short pelvic course; gives off superior vesical arteries, then obliterates, becoming medial umbilical ligament

Urinary bladder and, in some males, ductus deferens

Superior vesical

Patent part of umbilical artery

Usually multiple; pass to superior aspect of urinary bladder

Superior aspect of urinary bladder and distal ureter

Artery to ductus deferens

Superior or inferior vesical artery

Runs subperitoneally to ductus deferens

Ductus deferens

Obturator

Runs antero-inferiorly on lateral pelvic wall

Pelvic muscles, nutrient artery to head of femur and medial compartment of thigh

Inferior vesical

Passes subperitoneally giving rise to prostatic artery and occasionally the artery to the ductus deferens

Inferior aspect of urinary bladder, pelvic ureter, seminal glands, and prostate

Descends in pelvis to rectum

Seminal glands, prostate, and inferior part of rectum

Exits pelvis through greater sciatic foramen and enters perineum via lesser sciatic foramen

Main artery to perineum, including muscles and skin of anal and urogenital triangles; erectile bodies

Passes posteriorly and gives rise to parietal branches

Pelvic wall and gluteal region

Ascends anterior to sacro-iliac joint and posterior to common iliac vessels and psoas major

Iliacus, psoas major, quadratus lumborum muscles, and cauda equina in vertebral canal

Run on anteromedial aspect of piriformis to send branches into pelvic sacral foramina

Piriformis muscle, structures in sacral canal and erector spinae muscles

Descends retroperitoneally; traverses inguinal canal and enters scrotum

Abdominal ureter, testis and epididymis

Middle rectal

Anterior division of internal iliac artery

Internal pudendal Posterior division of internal iliac artery

Internal iliac artery

Iliolumbar Lateral sacral (superior and inferior) Testicular (gonadal)

Posterior division of internal iliac artery Abdominal aorta

Pe lvis an d Pe rin e um

418

LYMPHATIC DRAINAGE OF MALE PELVIS AND PERINEUM

Inferior mesenteric artery Lymph Nodes:

Abdominal aorta

Lumbar (caval/aortic) Inferior mesenteric Common iliac Internal iliac External iliac Superficial inguinal Deep inguinal Sacral Pararectal Direction of flow

Left ovarian artery Left common iliac artery Left ureter Left internal iliac artery Left external iliac artery

Urinary bladder Left femoral artery Prostatic urethra Spongy urethra

Intermediate urethra

A. Lymphatic Drainage of Pelvic Urinary System

Key for C: Path for lymph flow from: A glans penis B spongy urethra C skin of body of penis/scrotum D testis

B Prostate

Ductus deferens

B. Anterior View

5.28

Testis

A

Seminal gland

C

D

C. Anterior View

LYMPHATIC DRAINAGE OF MALE PELVIS AND PERINEUM

A. Pelvic urinary system . B. Internal genital organs. C. Penis, sp ongy urethra, scrotum and testis.

LYMPHATIC DRAINAGE OF MALE PELVIS AND PERINEUM

Pe lvis an d Pe rin e um

419

Sacrum

Urinary bladder Rectum

Prostatic urethra Anal canal

Prostate

Lymph Nodes

Spongy urethra

Ductus deferens

Glans penis

Epididymis Testis Scrotum

Lumbar (caval/aortic) Inferior mesenteric Common iliac Internal iliac External iliac Superficial inguinal Deep inguinal Sacral Pararectal

D. Medial View

LYMPHATIC DRAINAGE OF MALE PELVIS AND PERINEUM (continued )

5.28

D. Zones of pelvis and perineum initially draining into sp eci c groups of lym p h nodes.

TABLE 5.5

LYMPHATIC DRAINAGE OF MALE PELVIS AND PERINEUM

Lymph Node Group

Structures Typica lly Dra ining to Lymph Node Group

Lumbar

Gonads and associated structures (including testicular vessels), urethra, testis, epididymis, common iliac nodes

Inferior mesenteric nodes

Superiormost rectum, sigmoid colon, descending colon, pararectal nodes

Common iliac nodes

External and internal iliac lymph nodes

Internal iliac nodes

Inferior pelvic structures, deep perineal structures, sacral nodes, prostatic urethra, prostate, base of bladder, inferior part of pelvic ureter, inferior part of seminal glands, cavernous bodies, anal canal (above pectinate line), inferior rectum

External iliac nodes

Anterosuperior pelvic structures, deep inguinal nodes, superior aspect of bladder, superior part of pelvic ureter, upper part of seminal gland, pelvic part of ductus deferens, intermediate and spongy urethra

Super cial inguinal nodes

Lower limb, super cial drainage of inferolateral quadrant of trunk, including anterior abdominal wall inferior to umbilicus, gluteal region, super cial perineal structures, skin of perineum including skin and prepuce of penis, scrotum, peri-anal skin, anal canal inferior to pectinate line

Deep inguinal nodes

Glans of penis, distal spongy urethra, super cial inguinal nodes

Sacral nodes

Postero-inferior pelvic structures, inferior rectum

Pararectal nodes

Superior rectum

Pe lvis an d Pe rin e um

420

INNERVATION OF MALE PELVIC ORGANS

Innervation

White rami communicantes (communicating branches) Presynaptic sympathetic fiber (lumbar splanchnic nerve)

L1 L2L2

Postsynaptic sympathetic cell body Postsynaptic sympathetic fiber entering aortic/superior hypogastric plexus

Somatic Sympathetic Parasympathetic Mixed autonomic

Abdominal aorta Sympathetic trunk

Inferior mesenteric (prevertebral) ganglion Paravertebral sympathetic ganglion Aortic plexus

Lumbar splanchnic nerves

Superior hypogastric plexus Left hypogastric nerve (cut end)

Right common iliac artery

Left common iliac artery

Right hypogastric nerve

Gray rami communicantes (postsynaptic fibers to lower limb)

Lumbosacral trunk (L4–L5) Inferior hypogastric plexus

Sciatic nerve Urinary bladder Pelvic pain line

Pelvic splanchnic nerves arising from anterior rami of S2–S4 spinal nerves

Pudendal nerve (S2–S4) Internal urethral sphincter

Vesical (pelvic) nerve plexus

Prostate and prostatic nerve plexus

Sympathetic fiber to internal urethral sphincter

Somatic motor fiber Presynaptic parasympathetic fiber from inferior hypogastric plexus Intrinsic postsynaptic parasympathetic ganglion

Somatic sensory fibers Urethra

External urethral sphincter

External urethral orifice

Postsynaptic parasympathetic fiber

A. Anterior View

5.29

INNERVATION OF MALE PELVIS AND PERINEUM

A. Overview.

TABLE 5.6

EFFECT OF SYMPATHETIC AND PARASYMPATHETIC STIMULATION ON URINARY TRACT, GENITAL SYSTEM, AND RECTUM

Orga n, Tra ct, or System

Effect of Sympa thetic Stimula tion

Effect of Pa ra sympa thetic Stimula tion

Urinary tract

Vasoconstriction of renal vessels slows urine formation; internal sphincter of male bladder contracted to prevent retrograde ejaculation and maintain urinary continence

Inhibits contraction of internal sphincter of bladder in males; contracts detrusor muscle of the bladder wall causing urination

Genital system

Causes ejaculation and vasoconstriction resulting in remission of erection

Produces engorgement (erection) of erectile tissues of the external genitals

Rectum

Maintains tonus of internal anal sphincter; inhibits peristalsis of rectum

Rectal contraction (peristalsis) for defecation; inhibition of contraction of internal anal sphincter

The parasympathetic system is restricted in its distribution to the head, neck, and body cavities (except for erectile tissues of genitalia); otherwise, parasympathetic bers are never found in the body wall and limbs. Sympathetic bers, by comparison, are distributed to all vascularized portions of the body.

Pe lvis an d Pe rin e um

INNERVATION OF MALE PELVIC ORGANS

421

Lumbar splanchnic nerves Sympathetic trunk Lumbosacral trunk Left hypogastric nerve

Superior hypogastric plexus

Pelvic splanchnic nerves Inferior hypogastric plexus

Sacral splanchnic nerve Pelvic pain line

Prostatic plexus

Inferior anal nerve

Vesical plexus

Pudendal nerve

Dorsal nerve of penis

Cavernous nerves Perineal nerve Posterior scrotal nerves

Innervation Somatic Sympathetic Parasympathetic Mixed autonomic

B. Left Lateral View

INNERVATION OF MALE PELVIS AND PERINEUM (continued ) B. Innervation of prostate and external genitalia. • The prim ary function of the sacral sym pathetic trunks is to p rovide postsynaptic bers to the sacral plexus for sym pathetic innervation of the lower lim b. • The p eri-arterial p lexuses of the ovarian, sup erior rectal, and internal iliac arteries are m inor routes by which sym pathetic bers enter the pelvis. Their p rim ary function is vasom otion of the arteries they accom pany. • The hypog astric plexuses (sup erior and inferior) are networks of sym p athetic and visceral afferent nerve bers. • The sup erior hyp og astric p lexus carries b ers con veyed to and from the aortic (interm esenteric) p lexus b y the L3 an d L4 sp lanchnic nerves. The sup erior hyp og astric p lexus d ivid es into rig ht and left hyp og astric nerves that m erg e with the p arasym p athetic p elvic sp lanchnic nerves to form the inferior hyp og astric p lexuses.

5.29

• The bers of the inferior hypogastric plexuses continue to the pelvic viscera on which they form pelvic plexuses (e.g., prostatic nerve plexus). • The pelvic splanchnic nerves convey presynaptic parasym pathetic bers from the S2–S4 spinal cord segm ents, which m ake up the sacral out ow of the parasym p athetic system . • Visceral afferents conveying unconscious re ex sensation follow the course of the parasym pathetic bers retrogradely to the spinal sensory ganglia of S2–S4, as do those transm itting pain sensations from the viscera inferior to the pelvic p ain line (structures that do not contact the peritoneum plus the distal sigm oid colon and rectum ). Visceral afferent bers conducting pain from structures sup erior to the pelvic pain line (structures in contact with the peritoneum , except for the distal sigm oid colon and rectum ) follow the sym pathetic bers retrogradely to inferior thoracic and superior lum bar spinal ganglia.

Pe lvis an d Pe rin e um

422

ORGANS OF FEMALE PELVIS

Uterine tube Medial umbilical ligament in medial umbilical fold

Ovary

Broad ligament of uterus

Cervix

Round ligament of uterus

Recto-uterine pouch Recto-uterine fold

Uterus

Recto-uterine pouch Vesico-uterine pouch

Posterior fornix of vagina

Urinary bladder

Coccyx

Pubic symphysis

Anococcygeal body

Retropubic space

Levator ani

Retropubic fat Urethra

Rectum Vagina

Inferior pubic ligament

Ampulla of rectum

Labium minus

Anal canal Labium majus

A. Medial View

Vesico-uterine pouch Fundus of uterus Rectus Myometrium abdominis (M)

Body of uterus Endometrium (E)

Cervix of uterus (C) Vagina

M E M

Cervix

Sacrum Rectum (R)

C

Coccyx R

Urinary bladder

Fundus of uterus

Vagina

Endometrium

Endopelvic fascia

Myometrium

Pubic symphysis

B. Midsagittal US

5.30

Urinary bladder

C. Longitudinal (Median) Transabdominal US

FEMALE PELVIC ORGANS IN SITU

A. Median section. The adult uterus is typ ically anteverted (tipped anterosup eriorly relative to the axis of the vagina) and ante exed ( exed or bent anteriorly relative to the cervix, creating the angle of exion) so that its m ass lies over the bladder. The cervix, opening on

the anterior wall of the vagina, has a short, round, anterior lip and a long, thin, posterior lip. B. Midsagittal MRI of uterus. C. Median (transabdom inal) ultrasound im age. The urinary bladder is distended to displace the loops of bowel from the pelvis.

Pe lvis an d Pe rin e um

ORGANS OF FEMALE PELVIS

Median umbilical ligament in median umbilical fold

Urinary bladder

423

Paravesical fossa Medial umbilical ligament in medial umbilical fold Lateral umbilical fold (inferior epigastric artery)

Transverse vesical fold

Vesico-uterine pouch Round ligament of uterus

Deep inguinal ring

Uterus Round ligament of uterus Uterine tube Ligament of ovary

Broad ligament Recto-uterine fold

Broad ligament of uterus Uterine tube

Recto-uterine pouch

Suspensory ligament of ovary Pararectal fossa

Sigmoid colon

Ovarian vein Sigmoid mesocolon

Ovarian artery

Rectum Ureter

Ureter

D. Superior View

Urinary bladder

Urinary bladder Uterus

Vagina

Ovary Vagina

Rectus

Rectum

E. Median Section

Uterus

F. Median Section

Urinary bladder

FEMALE PELVIC ORGANS IN SITU (continued ) Round ligament

Fundus of uterus

Uterine tube Ovary

Rectum

G. Laparoscopic View of Normal Female Pelvis

Broad ligament

5.30

D. True pelvis with peritoneum intact, viewed from above. The uterus is usually asym m etrically placed. The round ligam ent of the fem ale takes the sam e subp eritoneal course as the ductus deferens of the m ale. E. Bim an ual p alp at io n o f ut e rin e ad n e xa (accessory structures, e.g., ovaries) F. Bim an ual p alp at io n of ut e rus. G. Lap aro sco p y involves inserting a laparoscope into the p eritoneal cavity through a sm all incision below the um bilicus. Insuf ation of inert gas creates a pneum operitoneum to provide space to visualize the pelvic organs. Additional openings (ports) can be m ade to introduce other instrum ents for m anipulation or to enable therapeutic procedures (e.g., ligation of the uterine tubes).

Pe lvis an d Pe rin e um

424

ORGANS OF FEMALE PELVIS

Aorta Inferior vena cava Ovarian artery Psoas major Sigmoid colon

Right ureter

Sigmoid mesocolon Internal iliac artery Uterine tube

External iliac artery

Ovary

Round ligament of uterus

Broad ligament of uterus

Uterine artery

Fundus of uterus Round ligament of uterus

Vaginal arteries

Trigone of urinary bladder Ureteric orifice Obturator externus Pubic bone Vestibule Crus of clitoris (cut ends)

A. Anterior View Nulliparous* adult

Multiparous** adult Postmenopausal

Puberty Newborn

Key

4-year-old

* Has never given birth ** Has given birth two or more times 2:1

1:1 2:1

B

1:1 2:1

5.31

3:1

FEMALE GENITAL ORGANS

A. Dissection. Part of the pubic bones, the anterior aspect of the bladder, and—on the specim en’s right side—the uterine tube, ovary, broad ligam ent, and peritoneum covering the lateral wall of the pelvis have been rem oved. B. Life t im e ch an g e s in ut e rin e

size an d p ro p o rt io n (body to cervical ratio, e.g., 2:1). All these stages represent norm al anatom y for the p articular age and reproductive status of the wom an.

ORGANS OF FEMALE PELVIS

Pe lvis an d Pe rin e um Perimetrium Myometrium Uterine wall Endometrium

Fundus of uterus

Round ligament of uterus Uterine cavity

Suspensory ligament of ovary

425

Ovary Uterine tube Ovarian artery Tubal branch of uterine artery Ovarian branch of uterine artery

Internal ostium

Uterine artery

Ligament of ovary

Cervical canal

Vaginal branch of uterine artery

Cervix Fornix of vagina External ostium Cervix (vaginal part)

Vaginal artery

Vagina

A. Anterior View

Suspensory ligament of ovary Uterine tube

Uterus

Round ligament of uterus

Uterine tube Abdominal ostium of uterine tube

Uterine artery

Broad ligament of uterus

Vaginal artery

Uterine artery

Ureter (with stone) Ureteric orifice Trigone of bladder

Ureter Vaginal artery Rectum

Vagina Fascia supporting vagina

Levator ani

Rod through urethra Labium minus Labium majus

B. Anterior View

UTERUS AND ITS ADNEXA A. Blood supp ly. On the specim en’s left side, part of the uterine wall with the round ligam ent and the vaginal wall have been cut away to exp ose the cervix, uterine cavity, and thick m uscular wall of the uterus, the m yom etrium . On the sp ecim en’s right side, the ovarian artery (from the aorta) and uterine artery (from the internal iliac) supply the ovary, uterine tube, and uterus and anastom ose

5.32 in the broad ligam ent along the lateral aspect of the uterus. The uterine artery sends a uterine branch to supply the uterine body and fundus and a vaginal branch to supply the cervix and vagina. B. Uterus and b road ligam ent. The p ubic bones and bladder, trigone excepted, are rem oved, as a continued dissection from Fig ure 5.31A.

426

Pe lvis an d Pe rin e um

ORGANS OF FEMALE PELVIS

Uterine tube Ovarian artery and veins

Ligament of ovary

Lateral cut in B Medial cut in B

Suspensory ligament of ovary Uterus Ovary Round ligament of uterus

A. Anterior View

Broad ligament

Suspensory ligament of ovary

Uterine tube: Ampulla Infundibulum Isthmus

Fimbriae

Round ligament of uterus (cut end) Uterine tube (cut end)

Ovarian artery

Uterine tube (cut end)

Uterus

Mesosalpinx* Round ligament of uterus

Ovary Mesovarium* Uterine artery

Round ligament of uterus Mesometrium*

B.

Anterolateral View

Ureter

Ligament of ovary

Uterine artery *parts of broad ligament

5.33

UTERUS AND BROAD LIGAMENT

A. and B. Two param edian sections show “m esenteries” with the pre x m eso-. “Salpinx” is the Greek word for trum p et or tube, and “m etro” for uterus. The m esentery of the uterus and uterine tube is called the broad ligam ent. The m ajor part of the broad ligam ent, the mesometrium , is attached to the uterus. The ovary is attached to the broad ligam ent by a m esentery of its own, called the mesovarium , to the uterus by the ligam ent of the ovary, and near the pelvic brim , by the suspensory ligam ent of the ovary containing the ovarian vessels. The p art of the b road ligam ent superior to the level of the m esovarium is called the mesosalpinx. C. Hyst e re ct o m y (excision of the uterus) is p erform ed through the lower anterior abdom inal wall or through the vagina. Because the uterine artery crosses sup erior to the ureter near the lateral fornix of the vagina, the ureter is in danger of being inadvertently clam ped or severed when the uterine artery is tied off during a hysterectom y.

Abdominal hysterectomy

Vaginal hysterectomy

C.

Medial View

ORGANS OF FEMALE PELVIS

Pe lvis an d Pe rin e um

427

Round ligament of uterus Peritoneum

Left external iliac artery

Round ligament of uterus

Uterine tube

Right ovarian artery

Isthmus Right external iliac artery Left ovarian artery

Obturator nerve

Ampulla

Mesosalpinx

Obturator nerve

Right ovary

Ligament of ovary

Tendinous arch of levator ani

Infundibulum

Obturator internus

Left ovary

Obturator fascia

Vesico-uterine pouch Urinary bladder Uterus Broad ligament Parts of Iliococcygeus levator ani Pubococcygeus

Right ureter Left ureter

D. Posterior View

Uterine artery

Vagina

Recto-uterine pouch

Uterine tube Ligament of ovary

Ampulla

Fundus of uterus

Infundibulum

Round ligament of uterus

Right ovary

Isthmus

Mesosalpinx

Fimbriae Abdominal ostium

Suspensory ligament of ovary (containing ovarian vessels)

Ligament of ovary Ovarian vessels

E. Posterior View

Broad ligament of uterus

Left ovary Cervix of uterus

UTERUS AND BROAD LIGAMENT (continued ) D. Uterus in situ. E. Uterus and adnexa, rem oved from cadaver.

External ostium of uterus

5.33

428

Pe lvis an d Pe rin e um

ORGANS OF FEMALE PELVIS

1 1 2

2

7

4

3

9

6 8

4

10

5

A. Transverse (Axial) US

B. Transverse (Axial) US

Urinary bladder (distended) (1 )

ANTERIOR

Broad ligament (6 )

Right ovary (2 )

Left ovary (7 )

Broad ligament (3 ) Uterus (4 )

Ovarian follicle (8 )

Intestine (5 )

Myometrium (10 )

Endometrium and endometrial canal (9 )

RIGHT

LEFT

POSTERIOR

Orientation Schematic for A and B

Distended urinary bladder Fundus of uterus Body of uterus

Urinary bladder Round ligament of uterus

Fundus and body of uterus

Ligament of ovary

External iliac artery and vein

Iliopsoas Gluteal muscles

Right ilium

Intestine Vagina Cervix

C. Longitudinal (Median) US

Sigmoid colon (filled with gas) Piriformis

Sacrum

D. Transverse CT

5.34

IMAGING OF UTERUS AND UTERINE ADNEXA

A. and B. Transverse ultrasound im ages. C. Longitudinal ultrasound im age. Tem porary retroversion and retro exion result when

a fully distended urinary bladder tem porarily retroverts the uterus and decreases the angle of exion. D. Transverse (axial) CT.

Pe lvis an d Pe rin e um

ORGANS OF FEMALE PELVIS

Fundus

429

UC Uterine tube P Uterine cavity

Body

c of uterus

Internal ostium (os)

P vs

Isthmus

Cervical canal

Cervix

B. Hysterosalpingogram of Normal Uterus, Anteroposterior View

External ostium (os)

Key for B

Vagina

Fornix of vagina

C

Uterine tubes Catheter in cervical canal

P Peritoneal cavity UC Uterine cavity

VS Vaginal speculum

A. Coronal Section

I Left uterus

I

Right uterus

Left cervix

Right cervix

Inferior View Septum

C. Posterior View

D. Hysterosalpingogram of Bicornuate Uterus, Anteroposterior View Key for D 1 and 2 Uterine cavities E Cervical canal

RADIOGRAPH OF UTERUS AND UTERINE TUBES (HYSTEROSALPINGOGRAM) A. Parts of uterus and sup erior vag ina. B. During h yst e ro salp in g o g rap h y, rad iop aq ue m aterial is injected into the uterus through external os of the uterus. If norm al, contrast m ed ium travels through the triangular uterine cavity (UC) and uterine tubes (arrowheads) and passes into the pararectal fossae (P) of the

F Uterine tubes I Isthmus of uterine tubes

5.35

peritoneal cavity. The fem ale genital tract is in direct com m unication with the peritoneal cavity and is, therefore, a potential pathway for the sp read of an infection from the vag ina and uterus. C. Illustration of duplicated uterus. D. Hysterosalp ing ogram of a bicornuate (“two-horned”) uterus.

Pe lvis an d Pe rin e um

430

ORGANS OF FEMALE PELVIS Small intestine Falciform ligament Fundus of uterus Placenta Chorionic lamina with blood vessels

Umbilicus (maternal)

Amniotic cavity (filled with amniotic fluid)

Umbilical cord (with umbilical arteries and vein)

Recto-uterine pouch

of cervical canal

Internal os Mucus plug

Peritoneum

External os Perimetrium Myometrium

Coccyx

of uterus

Linea alba Median umbilical ligament Cervix of uterus Vesico-uterine pouch

Rectal ampulla

Pubic symphysis Urinary bladder Vagina Urethra Perineal body

A. Median Section

9 10 8 7

5.36

PREGNANT UTERUS

A. Median section; fetus is intact. B. Mo n t h ly ch an g e s in size o f ut e rus d urin g p re g n an cy. Over the 9 m onths of pregnancy, the gravid uterus expands greatly to accom m odate the fetus, becom ing larger and increasingly thin walled. At the end of pregnancy, the fetus “drops,” as the head becom es engaged in the lesser pelvis. The uterus becom es nearly m em branous, with the fundus drop ping below its highest level (achieved in the 9th m onth), at which tim e it extends superiorly to the costal m argin, occupying m ost of the abdom inopelvic cavity.

6 5 4 3

B. Anterior View

ORGANS OF FEMALE PELVIS

Pe lvis an d Pe rin e um

431

C. Anteroposterior View

Maternal surface of placenta with cotyledons

Umbilical cord

Amnion

D. Maternal Surface of Placenta

PREGNANT UTERUS (continued ) C. Radiograph of fetus. D. Photograph of an 18-week-old fetus connected to the p lacenta by the um bilical cord.

5.36

Pe lvis an d Pe rin e um

432

VESSELS OF FEMALE PELVIS

Superior hypogastric plexus Ureter Left common iliac artery Left common iliac vein

Inferior mesenteric vessels

Ileum

Meso-appendix

Root of sigmoid mesocolon Ovarian vessels

Ileocecal fold

External iliac artery Internal iliac artery

Appendix

Ureter Uterus

Ovary Broad ligament (cut edge) Uterine tube (retracted)

Broad ligament Vaginal branch of uterine artery

Uterine artery

Inferior epigastric artery

Round ligament of uterus

Ureter

Rectum Trigone of urinary bladder

Pubic bone

Vaginal artery Vagina

Pubic symphysis

Anterior View

5.37

URETER AND RELATIONSHIP TO UTERINE ARTERY

• Most of the p ubic sym physis and m ost of the bladder (excep t the trigone) have been rem oved. • The left ureter is crossed by the ovarian vessels and nerves; the apex of the inverted V-shaped root of the sigm oid m esocolon is situated anterior to the left ureter.

• The left ureter crosses the external iliac artery at the bifurcation of the com mon iliac artery and then descends anterior to the internal iliac artery; its course is subperitoneal from where it enters the pelvis to where it passes deep to the broad ligam ent and is crossed by the uterine artery. In jury of th e uret er m ay occur in this region when the uterine artery is ligated and cut during hysterectom y.

Pe lvis an d Pe rin e um

VESSELS OF FEMALE PELVIS Arteries:

433

Abdominal aorta

Common iliac

Inferior mesenteric artery Iliolumbar

Internal iliac

Lateral sacral

External iliac

Median sacral artery

Superior

Obturator

Gluteal

Inferior

Deep circumflex iliac Inferior epigastric Medial umbilical ligament

Left common iliac artery

Uterine

Superior rectal artery Left internal iliac artery Left external iliac artery

Internal pudendal Middle rectal

Superior vesical

Vaginal

Urinary bladder

Lateral sacral arteries

Rectum

Vagina

A. Median Section Veins:

Internal iliac Superior gluteal

Common iliac

Lateral sacral

Deep circumflex iliac

Uterine

Inferior epigastric

Middle rectal R

Uterine venous plexus

Vagina Vesical venous plexus

B. Median Section

Uterine artery Left ureter Middle rectal artery Vaginal artery Spine of ischium Internal pudendal artery Levator ani Inferior rectal arteries Deep artery of clitoris Artery of vestibule of vagina Perineal artery External pudendal artery Femoral artery

Superior vesical artery Pubic symphysis

Internal pudendal

B

Uterus

Urinary bladder

Inferior gluteal

Obturator

Umbilical artery

Right ureter

Superior vesical External iliac

Ovaries

Crus of clitoris Dorsal artery of clitoris Anterior labial artery Posterior labial artery

Vaginal venous plexus

C. Anterolateral View

5.38

ARTERIES AND VEINS OF FEMALE PELVIS

TABLE 5.7

ARTERIES OF FEMALE PELVIS ( DERIVATIVES OF INTERNAL ILIAC ARTERY [IIA])

Artery

Origin

Course

Distribution

Anterior division of IIA

Internal iliac artery

Passes anteriorly along lateral wall of pelvis, dividing into visceral and obturator arteries

Pelvic viscera and muscles of superior medial thigh and perineum

Umbilical

Anterior div. IIA

Short pelvic course, gives off superior vesical arteries

Superior aspect of urinary bladder

Superior vesical artery

Patent umbilical a.

Usually multiple, pass to superior aspect of urinary bladder

Superior aspect of urinary bladder

Obturator

Runs antero-inferiorly on lateral pelvic wall

Pelvic muscles, ilium, femoral head, medial thigh

Uterine

Runs anteromedially between broad and cardinal ligs.; crosses ureter superiorly to lateral aspect of uterine cervix

Uterus, ligaments of uterus, medial parts of uterine tube and ovary, and superior vagina

Divides into vaginal and inferior vesical branches

Vaginal branch: lower vagina, vestibular bulb, and adjacent rectum; inferior vesical branch: fundus of urinary bladder

Middle rectal

Descends in pelvis to inferior part of rectum

Inferior part of rectum

Internal pudendal

Exits pelvis via greater sciatic foramen and enters perineum (ischio-anal fossa) via lesser sciatic foramen

Main artery to perineum including muscles of anal canal and perineum, skin and urogenital triangle and erectile bodies

Passes posteriorly and gives rise to parietal branches

Pelvic wall and gluteal region

Ascends anterior to sacro-iliac joint and posterior to common iliac vessels and psoas major muscle

Iliacus, psoas major, quadratus lumborum muscles, and cauda equina in vertebral canal

Runs on anteromedial aspect of piriformis muscle

Piriformis and erector spinae muscles, structures in sacral canal

Crosses pelvic brim and descends in suspensory ligament to ovary

Abdominal and/or pelvic ureter, ovary, and ampullary end of uterine tube

Vaginal

Posterior division of IIA Iliolumbar Lateral sacral Ovarian

Anterior division of internal iliac artery

Internal iliac artery Posterior division of internal iliac artery Abdominal aorta

434

Pe lvis an d Pe rin e um

LYMPHATIC DRAINAGE OF FEMALE PELVIS AND PERINEUM

Inferior mesenteric artery Left ovarian artery

Abdominal aorta

Lymph Nodes Lumbar (caval/aortic) Inferior mesenteric Common iliac Internal iliac External iliac Superficial inguinal Deep inguinal Sacral

Right common iliac artery Right internal iliac artery Right ureter

Direction of flow A Vulva B Glans clitoris, labia minora C Urethra

Right external iliac artery

Right femoral artery Urinary bladder

A. Pelvic Urinary System

B

B

Uterine tube and ovary

Uterus Vagina

A

B. Internal Genital Organs

C. Vulva

Anterior Views

5.39

C

LYMPHATIC DRAINAGE OF FEMALE PELVIS AND PERINEUM

LYMPHATIC DRAINAGE OF FEMALE PELVIS AND PERINEUM

Pe lvis an d Pe rin e um

435

Sacrum

Uterine tube Ovary Uterus

Urinary bladder Vagina

Rectum

Clitoris Urethra

Anal canal

D.

Lymph Nodes Lumbar (caval/aortic) Inferior mesenteric Common iliac Internal iliac External iliac Superficial inguinal Deep inguinal Sacral Pararectal

LYMPHATIC DRAINAGE OF FEMALE PELVIS AND PERINEUM (continued )

5.39

D. Zones of pelvis and perineum initially draining to sp eci c groups of regional nodes.

TABLE 5.8

LYMPHATIC DRAINAGE OF STRUCTURES OF FEMALE PELVIS AND PERINEUM

Lymph Node Group

Structures Typica lly Dra ining to Lymph Node Group

Lumbar

Gonads and associated structures (along ovarian vessels), ovary, uterine tube (except isthmus and intra-uterine parts), fundus of uterus, common iliac nodes

Inferior mesenteric

Superiormost rectum, sigmoid colon, descending colon, pararectal nodes

Common iliac

External and internal iliac lymph nodes

Internal iliac

Inferior pelvic structures, deep perineal structures, sacral nodes, base of bladder, inferior pelvic ureter, anal canal (above pectinate line), inferior rectum, middle and upper vagina, cervix, body of uterus, sacral nodes

External iliac

Anterosuperior pelvic structures, deep inguinal nodes, superior bladder, superior pelvic ureter, upper vagina, cervix, lower body of uterus

Super cial inguinal

Lower limb, super cial drainage of inferolateral quadrant of trunk, including anterior abdominal wall inferior to umbilicus, gluteal region, superolateral uterus (near attachment of round ligament), skin of perineum including vulva, ostium of vagina (inferior to hymen), prepuce of clitoris, peri-anal skin, anal canal inferior to pectinate line

Deep inguinal

Glans of clitoris, super cial inguinal nodes

Sacral

Postero-inferior pelvic structures, inferior rectum, inferior vagina

Pararectal

Superior rectum

436

Pe lvis an d Pe rin e um

INNERVATION OF FEMALE PELVIC ORGANS

Upper lumbar sympathetic trunk

Spinal ganglia (posterior root ganglia) T12 L1 L2

L3 Lumbar splanchnic nerves

Innervation Visceral afferents running with parasympathetic fibers Presynaptic Postsynaptic

Parasympathetic

L4 Spinal sensory ganglia Pelvic splanchnic nerves

L5 S1

Visceral afferents running with sympathetic fibers Presynaptic Postsynaptic

Prevertebral (sympathetic) ganglia

Sympathetic

Somatic motor Somatic afferent

S2

Pelvic plexus

S3 S4

Abdominal aortic plexus

S5

Sacral plexus

Superior hypogastric plexus

5.40

INNERVATION OF FEMALE PELVIC VISCERA

• Pelvic splanchnic nerves (S2–S4) sup ply p arasym pathetic m otor bers to the uterus and vagina (and vasodilator bers to the erectile tissue of the clitoris and bulb of the vestibule; not shown). • Presynap tic sym p athetic bers p ass through the lum bar splanchnic nerves to synap se in prevertebral ganglia; the postsynaptic bers travel through the sup erior and inferior hyp ogastric plexuses to reach the pelvic viscera. • Visceral afferent bers conducting p ain from intraperitoneal viscera travel with the sym pathetic bers to the T12–L2 spinal g anglia. Visceral afferent bers conducting pain from subperitoneal viscera travel with parasym pathetic bers to the S2–S4 sp inal ganglia. • Som atic sensation from the opening of the vagina also passes to the S2–S4 spinal ganglia via the pudendal nerve. • Muscular contractions of the uterus are horm onally induced.

Inferior hypogastric plexuses

Ovarian plexus Pelvic plexus Uterovaginal plexus Intrinsic (parasympathetic) ganglia Perineal muscles Anterior View

Uterine plexus

Pudendal nerve

Pelvic intraperitoneal viscera Lower limit of peritoneum (pelvic pain line) Pelvic plexus

Pelvic subperitoneal viscera

Pudendal nerve Perineum

INNERVATION OF FEMALE PELVIC ORGANS

Pe lvis an d Pe rin e um

437

Sympathetic trunk Lumbar splanchnic nerves

Spinal (posterior root) ganglia T12–L2(3)

Abdominal aortic plexus

L3/4

A. Spinal block via

lumbar puncture (anesthetizes from waist down—intraand subperitoneal plus somatic areas)

Pelvic splanchnic nerves

Superior and inferior hypogastric plexuses Spinal (posterior root) ganglia, S2–S4 Uterovaginal plexus (part of pelvic plexus)

Needle tip entering sacral canal

Pelvic pain line (inferior limit of peritoneum)

B. Caudal

Pudendal nerve

epidural block (anesthetizes subperitoneal plus somatic areas innervated by pudendal nerve)

Key Intraperitoneal viscera Subperitoneal viscera Somatic structures

C. Pudendal nerve block (anesthetizes area innervated by pudendal nerve)

INNERVATION OF PELVIC VISCERA—OBSTETRICAL NERVE BLOCKS • A sp in al b lock, in which the anesthetic agent is introduced with a needle into the spinal subarachnoid space at the L3–L4 vertebral level, produces com plete anesthesia inferior to approxim ately the waist level. The perineum , p elvic oor, and birth canal are anesthetized, and m otor and sensory functions of the entire lower lim b s, as well as sensation of uterine contractions, are tem porarily elim inated. • With the caud al e p id ural b lo ck, the anesthetic ag ent is adm inistered using an in-dwelling catheter in the sacral canal. The entire

5.41

birth canal, pelvic oor, and m ost of the perineum are anesthetized, but the lower lim bs are not usually affected. The m other is aware of her uterine contractions. • A p u d e n d a l n e rve b lo ck is a p erip heral nerve b lock that p rovid es local anesthesia over the S2–S4 d erm atom es (m ost of the p erineum ) and the inferior q uarter of the vag ina. It d oes not b lock p ain from the sup erior b irth canal (uterine cervix and sup erior vag ina), so the m other is ab le to feel uterine contractions.

Pe lvis an d Pe rin e um

438

INNERVATION OF FEMALE PELVIC ORGANS

Uterine tube Suspensory ligament of ovary Peritoneum

Round ligament of uterus

Ovary

Recto-uterine fold

Uterine tube Round ligament

Ligament of ovary Vessels in broad ligament

Removed from A Appendix Meso-appendix Suspensory ligament of ovary Peritoneum (cut edge) Round ligament of uterus

Endopelvic fascia

Section of broad ligament Uterus Pubic symphysis Uterosacral ligament Rectum

A. Medial View

5.42

Vagina

Posterior fornix of vagina

Recto-uterine fold Recto-uterine pouch

SERIAL DISSECTION OF AUTONOMIC NERVES OF FEMALE PELVIS

A. Broad lig am ent and p eritoneum of the lateral wall of the p elvic cavity have been rem oved to exp ose the endopelvic fascia.

INNERVATION OF FEMALE PELVIC ORGANS

Pe lvis an d Pe rin e um

Lymph node

439

Sacrum (S1 segment)

Right and left hypogastric nerves Uterus pulled medially

Peritoneum (cut edge) 3

2

4

Twigs from sympathetic trunk (sacral splanchnic nerves)

Suspensory ligament of ovary

Pelvic splanchnic nerves (anterior rami of S3 and S4)

1 Endopelvic fascia

Recto-uterine fold 1. Pubic symphysis 2. Urinary bladder 3. Uterus 4. Rectum

Uterus (pulled medially)

Coccyx

Urinary bladder

Recto-uterine pouch

B. Medial View

Rectum

Sacrum (S1 segment) Hypogastric nerve Sympathetic ganglion Peritoneum (cut edge)

Sympathetic trunk Anterior ramus S3 Ureter Uterine artery

Anterior ramus S4

Endopelvic fascia (cut edge)

Peritoneum (cut edge)

Right inferior hypogastric plexus and ganglion

Recto-uterine fold

Uterovaginal plexus Uterus Urinary bladder

Coccyx Recto-uterine pouch Rectum

C. Medial View

SERIAL DISSECTION 5.42 OF AUTONOMIC NERVES OF FEMALE PELVIS (continued ) B. The rectum and endopelvic fascia have been re ected anteriorly to expose the hypogastric nerves, sympathetic trunk, and pelvic splanchnic nerves (parasym pathetic). C. The sub peritoneal fatty-areolar tissue has been rem oved and the inferior hypogastric plexus exposed. The inferior hypogastric plexus continues as the uterovaginal plexus and supplies the uterus, uterine tubes, vagina, urethra, greater vestibular glands, erectile tissue of the clitoris, and bulb of the vestibule.

Pe lvis an d Pe rin e um

440

Femoral vein Femoral artery Femoral nerve Profunda femoris artery Obturator nerve

SUBPERITONEAL REGION OF PELVIS

Urethra

Pubic symphysis

Pubis Urinary bladder

Pectineus

Sartorius Rectus femoris Iliacus Tensor fasciae latae

Obturator artery Obturator vein

Tendon of psoas major

Hip joint

Obturator membrane

Vastus lateralis Levator ani (puborectalis)

Neck of femur Obturator externus

Vagina

Ischial tuberosity

Internal pudendal vessels

Gluteus maximus Inferior gluteal artery

Sciatic nerve Inferior gluteal nerve

Posterior cutaneous nerve of the thigh Peritoneum of recto-uterine pouch

Rectum

Anococcygeal ligament

Obturator internus Pudendal nerve Ischio-anal fossa

A. Transverse Section, Superior View Pubic symphysis

Pubis

Femoral vein

Femoral artery Pubic symphysis

Pubis

Femoral vein

Femoral artery

Adductor muscles Obturator nerve and vessels

Ur

Ur

Obturator externus

V

V

Obturator internus

RF

R LA Pd

R

Ischial tuberosity Ischio-anal fossa

Pd LA

Gluteus maximus

Gluteal cleft

B. Transverse MRI

C Key for B and C

5.43

TRANSVERSE SECTIONS AND MRIs THROUGH FEMALE PELVIS

A. Transverse section through the ischial tuberosities, bladd er, vagina, rectum , and rectouterine pouch. B. Transverse (axial) MRI. C. Sectioned specim en.

LA Pd R RF Ur V

Levator ani Pudendal nerve and vessels Rectum Recto-uterine fold Urethra Vagina

SUBPERITONEAL REGION OF PELVIS Median umbilical ligament

Medial umbilical ligament Vesical fascia

Pe lvis an d Pe rin e um

441

Rectus abdominis Pubic symphysis Umbilical (prevesical) fascia

Urinary bladder

Dorsal vein of clitoris

Lateral ligament of bladder

Medial Pubovesical Lateral ligaments

Round ligament Superior vesical artery

Inferior epigastric vessels

Inferior vesical and vaginal arteries within paracolpium

Deep inguinal ring Superior fascia of levator ani

Ureter

Tendinous arch of levator ani

Cervix

Obturator vessels

Suspensory ligament of ovary

Obturator fascia

Ovarian artery Vesicocervical (vesicovaginal) space

Hypogastric sheath

Iliac fascia Tendinous arch of pelvic fascia Psoas fascia

External iliac artery and vein

Psoas

Internal iliac artery and vein

Uterine artery

Uterosacral ligament

A. Superior View

Presacral fascia

Middle rectal artery Rectum

Retrorectal (presacral) space Sacrum

Key Tendinous arch of pelvic fascia

ANTERIOR

Pubic symphysis Pubovesical ligament Vesical fascia Tendinous arch of levator ani

Cervix Transverse cervical ligament Recto-uterine pouch Rectum

B. Superior View

Sacrum POSTERIOR

Rectovaginal space Median sacral vessels

PELVIC FASCIA AND SUPPORTING MECHANISM OF CERVIX AND UPPER VAGINA

Retropubic space (opened)

Urinary bladder

Transverse cervical (cardinal) ligament

Uterosacral (recto-uterine ligament) Rectal fascia Presacral space (opened)

5.44

A. Greater and lesser pelvis dem onstrating pelvic viscera and endopelvic fascia. B. Schem atic illustration of fascial ligam ents and areolar spaces at the level of tendinous arch of pelvic fascia. • Note the p arietal p elvic fascia covering the obturator internus and levator ani m uscles and the visceral pelvic fasciae are continuous where the organs p enetrate the pelvic oor, form ing a tendinous arch of pelvic fascia bilaterally. • The endopelvic fascia lies between, and is continuous with, both visceral and parietal layers of pelvic fascia. The loose, areolar portions of the endopelvic fascia have been rem oved; the brous, condensed portions rem ain. Note the condensation of this fascia into the hypogastric sheath, containing the vessels to the p elvic viscera, the ureters, and (in the m ale) the ductus deferens. • Observe the ligam entous extensions of the hyp ogastric sheath: the lateral ligam ent of the urinary bladder, the transverse cervical ligam ent at the base of the broad ligam ent, and a less prom inent lam ina posteriorly containing the m iddle rectal vessels.

442

Pe lvis an d Pe rin e um

SURFACE ANATOMY OF PERINEUM

Scrotum

Scrotal raphe

Perineal raphe

Anus

A. Inferior View, penis/scrotum retracted anteriorly

Pubic hairs covering pubic region

Root of penis Body of penis Corona of glans Glans penis Scrotum

Perineal raphe

Anus

B. Inferior View

5.45

SURFACE ANATOMY OF MALE PERINEUM

A. Center of m ale p erineal region. B. Penis, scrotum , and anal region.

SURFACE ANATOMY OF PERINEUM

Pe lvis an d Pe rin e um

443

Mons pubis

Anterior commissure of labia majora

Prepuce of clitoris

Labium majus Labium minus

A. Anterior View

Prepuce of clitoris Labium majus

Glans of clitoris

Labium minus External urethral orifice Hymenal caruncle Vaginal orifice Frenulum of labia minora Posterior commissure of labia majora

Site of perineal body

Anus

B. Antero-inferior View (Lithotomy Position)

SURFACE ANATOMY OF THE FEMALE PERINEUM

5.46

A. External genitalia (pudendum ; vulva), standing p osition. B. Vestibule of vag ina and the external urethral and vaginal ori ces opening into it (recum bent position).

Pe lvis an d Pe rin e um

444

OVERVIEW OF MALE AND FEMALE PERINEUM Mons pubis and pubic crest Scrotum Clitoris Central point of perineum Site of gluteal fold Intergluteal (natal) cleft

A

Coccyx

Male Inferior Views (Lithotomy Position)

Female

Key Line dividing perineal region into urogenital triangle (anterior to line) and anal triangle

Outline of perineal region Palpable bony feature

Urethra External urethral orifice Vaginal orifice Ischiocavernosus Raphe of bulbospongiosus Bulbospongiosus Superficial transverse perineal

Bulb of vestibule

Perineal body

B. Inferior Views

Anus External anal sphincter

Dorsal nerve and vessels of penis Dorsal nerve and vessels of clitoris

C. Inferior Views

Deep perineal vessels covered with perineal membrane

External urethral sphincter Compressor urethrae Bulbo-urethral gland within deep transverse perineal Urethrovaginal sphincter Deep transverse perineal

D. Inferior Views

5.47

LAYERS OF PERINEUM

Smooth muscle

Greater vestibular gland

Pe lvis an d Pe rin e um

OVERVIEW OF MALE AND FEMALE PERINEUM

445

Urethra Vagina Urogenital hiatus Rectum

Pubococcygeus (1) Iliococcygeus (2) Coccygeus (3) (1 + 2 Levator ani) (1 + 2 + 3 Pelvic diaphragm)

E

Inferior Views

5.47

LAYERS OF PERINEUM (continued ) A–E. The layers are shown from super cial to deep. TABLE 5.9

MUSCLES OF PERINEUM

Muscle

Origin

Course a nd Insertion

Innerva tion

Ma in Action

External anal sphincter

Skin and fascia surrounding anus; coccyx via anococcygeal ligament Male: median raphe on ventral surface of bulb of penis; perineal body

Passes around lateral aspects of anal canal; insertion into perineal body

Inferior anal (rectal) nerve, a branch of pudendal nerve (S2–S4)

Constricts anal canal during peristalsis, resisting defecation; supports and xes perineal body and pelvic oor Male: supports and xes perineal body/pelvic oor; compresses bulb of penis to expel last drops of urine/semen; assists erection by compressing out ow via deep perineal vein and by pushing blood from bulb into body of penis Female: supports and xes perineal body/pelvic oor; “sphincter” of vagina; assists in erection of clotiris (and perhaps bulb of vestibule); compresses greater vestibular gland Maintains erection of penis or clitoris bycompressing out ow veins and pushing blood from the root of penis or clitoris into the body of penis or clitoris Supports and xes perineal body (pelvic oor) to support abdominopelvic viscera and resist increased intra-abdominal pressure

Bulbospongiosus

Female: perineal body

Ischiocavernosus

Super cial transverse perineal Deep transverse perineal (male only) Smooth muscle (female only) External urethral sphincter Compressor urethrae (females only) Urethrovaginal sphincter (females only)

Internal surface of ischiopubic ramus and ischial tuberosity

Internal surface of ischiopubic ramus and ischial tuberosity

Ischiopubic rami

Internal surface of ischiopubic ramus Anterior side of urethra

Male: surrounds lateral aspects of bulb of penis and most proximal part of body of penis, inserting into perineal membrane, dorsal aspect of corpora spongiosum and cavernosa, and fascia of bulb of penis Female: passes on each side of lower vagina, enclosing bulb and greater vestibular gland; inserts onto pubic arch and fascia of corpora cavernosa of clitoris Embraces crus of penis or clitoris, inserting onto the inferior and medial aspects of the crus and to the perineal membrane medial to the crus Passes along inferior aspect of posterior border of perineal membrane to perineal body Passes along superior aspect of posterior border of perineal membrane to perineal body, and external anal sphincter Passes to lateral wall of urethra and vagina Surrounds urethra superior to perineal membrane; in males, also ascends anterior aspect of prostate Continuous with external urethral sphincter Continuous with compressor urethrae; extends posteriorly on lateral wall of urethra and vagina to interdigitate with bers from opposite side of perineal body

Muscular (deep) branch of perineal nerve, a branch of the pudendal nerve (S2–S4)

Muscular (deep) branch of perineal nerve Autonomic nerves

Dorsal nerve of penis or clitoris, terminal branch of pudendal nerve (S2–S4)

Quantity of smooth muscle increases with age; function uncertain Compresses urethra to maintain urinary continence

Compresses urethra; with pelvic diaphragm assists in elongation of urethra Compresses urethra and vagina

Oelrich TM. The urethral sphincter muscle in the male. Am J Anat 1980;158:229–246. Oelrich TM. The striated urogenital sphincter muscle in the female. Anat Rec 1983;205:223–232. Mirilas P, Skandalakis JE. Urogenital diaphragm: an erroneous concept casting its shadow over the sphincter urethrae and deep perineal space. J Am Coll Surg 2004;198:279–290. DeLancey JO. Correlative study of paraurethral anatomy. Obstet Gynecol 1986;68:91–97.

446

Pe lvis an d Pe rin e um

OVERVIEW OF MALE AND FEMALE PERINEUM Bladder Retropubic space

Peritoneum

Fascia

*Superficial fascia *Deep fascia

Rectum

*Membranous fascia

Rectovesical septum External urethral sphincter

*Fatty fascia *Suspensory ligament of penis

Anococcygeal ligament

Perineal membrane

Deep postanal space

*Deep (Buck) fascia of penis B

*Perineal body

E

Superficial perineal pouch

*Dartos fascia *Perineal fascia (Colles fascia) *Dartos fascia Plane of A

C

Visceral fascia

Urinary bladder

A. Median Section of Male

Peritoneum Obturator internus

*Obturator fascia Tendinous arch of levator ani Levator ani

*Inferior fascia of pelvic diaphragm

Prostate

Ischio-anal fossa External urethral sphincter

Bulbo-urethral gland

*Perineal membrane

Crus of penis

*Deep (investing) perineal fascia *Perineal fascia Skin

Ischiocavernosus Bulb of penis

Spongy urethra

Superficial perineal pouch Bulbocavernosus

B. Anterior View of Coronal Section in Plane Indicated in A

Linea alba *Fundiform ligament of penis

Pubic symphysis Pubic bones Deep dorsal vein

*Suspensory ligament of penis *Fascia latae

Corpora cavernosa penis

*Dartos fascia of penis *Deep fascia of penis Spongy urethra Skin

Corpus spongiosum *Septum of scrotum *Dartos muscle (dashed line) *Dartos fascia of scrotum

C. Anterior View of Coronal Section in Plane Indicated in A

5.48

FASCIAE OF PERINEUM

A–C. Male p erineum .

OVERVIEW OF MALE AND FEMALE PERINEUM Uterovaginal fascia

Cervix

*Vesical

447

Peritoneum

Uterus

Peritoneum

Pe lvis an d Pe rin e um

Rectal fascia

fascia

Rectum Vagina Deep perineal pouch with endopelvic fascia

Rectovaginal septum

*Fatty (Camper) fascia Anococcygeal ligament

*Membranous (Scarpa) fascia

Deep postanal space Bladder

E

F

Perineal body

Superficial perineal pouch External urethral sphincter

*Perineal fascia (Colles fascia) *Perineal membrane

D. Median Section of Female Plane of D

Cervix

Base of broad ligament

Peritoneum Obturator internus *Obturator fascia Tendinous arch of levator ani

Cardinal ligament

Levator ani

*Inferior fascia of

Paracolpium

pelvic diaphragm

Vagina

Ischio-anal fossa External urethral sphincter

Compressor urethrae

*Perineal membrane *Deep (investing) perineal fascia *Perineal fascia

Ischiocavernosus Superficial perineal pouch Bulb of vestibule

Vestibule of vagina

Bulbospongiosus

Skin

E. Anterior View of Coronal Section in Plane Indicated in D Peritoneum

Obturator internus

Ischium

*Obturator fascia

*Superior fascia of pelvic diaphragm

Pudendal canal

*Inferior fascia of pelvic diaphragm

Ischio-anal fat pad

Pelvic diaphragm Anus

External anal sphincter

F. Anterior View of Coronal Section in Plane Indicated in D

FASCIAE OF PERINEUM (continued ) D–F. Fem ale perineum .

5.48

448

Pe lvis an d Pe rin e um

OVERVIEW OF MALE AND FEMALE PERINEUM

Bladder Rectum

Urinary bladder

Prostate External urethral sphincter Deep transverse perineal

Pubis

Compressor urethrae Coccyx

B. Male, Right Lateral View Male Puboprostaticus Pubococcygeus Puborectalis

Prostate

Muscle of uvula Urethra

Rectovesicalis

A. Left Lateral View, Male

Muscles compressing urethra: Internal urethral sphincter Pubovesicalis External urethral sphincter

Vagina

Bladder Rectum

Vaginal wall

External urethral sphincter

Urinary bladder

Pubis

Compressor urethrae Urethrovaginal sphincter

Urethra Coccyx

Vagina

D. Female, Left Lateral View

Deep transverse perineal

Female Pubovesicalis Pubococcygeus Urethra

Perineal body

C. Left Lateral View, Female

Puborectalis Rectovesicalis Muscles compressing urethra: Compressor urethrae External urethral sphincter Muscles compressing vagina: Pubovaginalis

5.49

SUPPORTING AND COMPRESSOR/ SPHINCTERIC MUSCLES OF PELVIS

A. Male. B. Male urethral sp hincters. C. Fem ale. D. Fem ale urethral sp hincters.

Urethrovaginal sphincter (part of external urethral sphincter) Bulbospongiosus

MALE PERINEUM

Pe lvis an d Pe rin e um

449

Corpora cavernosa Corpus spongiosum Membranous layer of subcutaneous tissue of perineum (Colles fascia) Posterior scrotal nerves Posterior scrotal artery Bulbospongiosus

Ischiocavernosus

Perineal membrane

Perineal branch of posterior cutaneous nerve of thigh

Perineal body Superficial transverse perineal Anal canal

Obturator fascia forming pudendal canal

Ischial tuberosity

Inferior anal (rectal) nerve

External anal sphincter

Levator ani Gluteus maximus

Perineal branch of S4 Inferior anal artery

Inferior View Ischio-anal fossa

Anococcygeal body Levator ani

DISSECTION OF MALE PERINEUM I Sup e r cial d isse ct io n . • The m em branous layer of subcutaneous tissue of the perineum was incised and re ected, opening the subcutaneous perineal com partm ent (p ouch) in which the cutaneous nerves course. • The perineal m em brane is exposed between the three paired m uscles of the super cial com partm ent; although not evident here, the m uscles are individually ensheathed with investing fascia. • The anal canal is surrounded by the external anal sphincter. The sup er cial b ers of the sphincter anchor the anal canal anteriorly to the perineal body and posteriorly, via the anococcygeal body (ligam ent), to the coccyx and skin of the gluteal cleft.

Gluteal cleft

5.50 • Ischio-anal (ischiorectal) fossae, from which fat bodies have been rem oved, lie on each side of the external anal sphincter. The fossae are also bound m edially and superiorly by the levator ani, laterally by the ischial tuberosities and obturator internus fascia, and p osteriorly by the gluteus m axim us overlying the sacrotuberous ligam ents. An anterior recess of each ischio-anal fossa extends sup erior to the p erineal m em brane. • In the lateral wall of the fossa, the inferior anal (rectal) nerve em erges from the p udend al canal and, with the p erineal branch of S4, supp lies the voluntary external anal sphincter and perianal skin; m ost cutaneous twigs have been rem oved.

450

Pe lvis an d Pe rin e um

MALE PERINEUM

Crus of penis Prostate Bulb of penis Perineal membrane Pubococcygeus (levator ani)

Internal anal sphincter

Perineal body (cut) Deep Superficial Subcutaneous

Parts of external anal sphincter

Incised external anal sphincter Ischial tuberosity Musculofibrous continuation of longitudinal layer of rectum Obturator fascia Sacrotuberous ligament Gluteus maximus

Iliococcygeus (levator ani)

Ischio-anal fossa

Gluteus maximus

A. Inferior View

5.51

Anococcygeal body

Coccyx

DISSECTION OF THE MALE PERINEUM II

A. The sup er cial perineal m uscles have been rem oved, revealing the roots of the erectile bodies (crura and bulb) of the penis, attached to the ischiop ubic ram i and perineal m em brane. On the left side, the sup er cial and deep parts of the external anal sphincter were incised and re ected; the underlying m usculo brous continuation of the outer longitudinal layer of the m uscular layer of the rectum is cut to reveal thickening of the inner circular layer that com prises the internal anal sphincter. B. Rup t ure o f t h e sp o n g y ure t h ra in t h e b ulb o f t h e p e n is results in extravasation (abnorm al passage) of urine into the subcutaneous perineal com partm ent. The attachm ents of the m em branous layer of subcutaneous tissue determ ine the direction and restrictions of ow of the extravasated urine. Urine and blood m ay pass deep to the continuations of the m em branous layer in the scrotum , penis, and inferior abdom inal wall. The urine cannot pass laterally and inferiorly into the thighs because the m em branous layer fuses with the fascia lata (deep fascia of the thigh) nor posteriorly into the anal triangle due to continuity with the perineal m em brane and perineal body.

Membranous layer of superficial abdominal (Scarpa) fascia Bloody extravasation Perforation of spongy urethra

Deep (Buck) fascia of penis Intercavernous septum

Fatty layer of perineal fascia

Dartos fascia

Bloody extravasation

B. Medial View (from Left)

Deep (Buck) fascia of penis (perforated) Membranous layer of perineal (Colles) fascia

MALE PERINEUM

Pe lvis an d Pe rin e um

451

Pubic symphysis

Prostate

Puboprostatic ligament

Prostatic urethra

Puborectalis

Rectovesical septum Border of urogenital hiatus

Levator prostatae Internal anal sphincter

Perineal body/rectovesical septum Deep transverse perineal (cut end)

* Pubococcygeus

Ischiopubic ramus Musculofibrous continuation of longitudinal muscular layer of rectum

External anal sphincter

* Iliococcygeus

Ischial tuberosity

* Coccygeus

* Collectively constitute pelvic diaphragm

Sacrotuberous ligament

External anal sphincter (subcutaneous part)

Skin around anus

A. Inferior View

Tip of coccyx

Peritoneum Bladder Prostate Bloody extravasation Pubic symphysis Torn and separated intermediate part of urethra External urethral sphincter

B. Medial View (from Left)

Perineal membrane

DISSECTION OF THE MALE PERINEUM III

5.52

A. The perineal m em brane and structures super cial to it have been rem oved. The prostatic urethra, base of the prostate, and rectum are visible through the urogenital hiatus of the pelvic diaphragm . The osseo brous boundaries are dem onstrated. B. Rup t ure o f t h e in t e rm e d iat e p art o f t h e ure t h ra results in extravasation of urine and blood into the deep perineal com partm ent. The uid m ay pass superiorly through the urogenital hiatus and distribute extraperitoneally around the prostate and bladder.

452

Pe lvis an d Pe rin e um

MALE PERINEUM

Spongy urethra

Prepuce

Pubic hair covering pubic region

Glans of penis

Root of penis Scrotum Body of penis

B. Right Anterolateral View Corona of penis External urethral orifice

Glans penis

Scrotum

Glans penis

Navicular fossa

Frenulum of prepuce

Urethral lacuna

A. Anterior View Orifices of urethral glands Superficial (external) inguinal ring

Corpus spongiosum penis

External spermatic fascia

Skin

Spongy (penile) urethra

Testicular artery Pampiniform plexus of veins Ilio-inguinal nerve

D. Urethral Aspect of Distal Penis

Suspensory ligament of penis Deferent duct (ductus deferens) Deep dorsal vein of penis Dorsal artery of penis Dorsal nerve of penis Epididymis External spermatic fascia Testis Glans penis

C. Anterior View

5.53

GLANS, PREPUCE, AND NEUROVASCULAR BUNDLE OF PENIS

A. Surface anatom y, p enis circum cised. B. Uncircum cised penis. C. Vessels and nerves of penis and contents of sperm atic cord. The super cial and deep fasciae covering the penis are rem oved to expose the m idline deep dorsal vein and the bilateral dorsal arteries and nerves of the penis. D. Sp ongy urethra, interior. A longitudinal incision was m ade on the urethral surface of the penis and carried through the oor of the urethra, allowing a view of the dorsal surface of the interior of the urethra.

Pe lvis an d Pe rin e um

MALE PERINEUM Dorsal artery

Superficial dorsal vein

Dorsal nerve

Anastomosis of veins

453

Deep dorsal vein Corona of glans penis Prepuce or foreskin

Glans penis

External urethral orifice

A. Lateral View Skin

Right seminal gland

Deep fascia of penis

Corpus spongiosum (contains spongy urethra)

Frenulum of prepuce Encircling vessels and nerves

Urinary bladder Corpora cavernosa, right and left * Intrabulbar fossa

Prostate

Neck of glans Corona of glans

Seminal colliculus

Navicular fossa

Bulbo-urethral gland and duct

Root of penis

Bulb

External urethral orifice

Corpus spongiosum*

B: Parts of Male Urethra

*Body of penis

Crura

Intramural (preprostatic) Prostatic Intermediate (membranous) Spongy (penile)

Glans penis

B. Lateral View Anterior rami

S2 S3 C: Pudendal Nerve and Branches, by Region

S4

Deep perineal pouch Dorsum of penis Superficial perineum

Pudendal nerve Inferior anal (rectal) nerve Perineal nerve: Muscular (deep) branches Superficial branch Posterior scrotal nerves

C.

Dorsal nerve of penis

Pelvis Gluteal region Pudendal canal

URETHRA, LAYERS, AND NERVES OF PENIS

5.54

A. Dissection. The skin, subcutaneous tissue, and deep fascia of the p enis and prep uce are re ected separately. B. Parts of m ale urethra. C. Distribution of pudendal nerve, right hem ipelvis. Five regions transversed by the nerve are dem onstrated. An uncircum cised p repuce covers all or m ost of the g lans penis. The prepuce is usually suf ciently elastic to allow retraction over the glans. In som e m ales, it is tight and cannot be retracted easily (phim osis), if at all. Secretions (sm egm a) m ay accum ulate in the preputial sac, located between the glans penis and prepuce, causing irritation. Circum cisio n exposes m ost, or all, of the glans.

Pe lvis an d Pe rin e um

454

MALE PERINEUM

Left ureter Right ureter

Urachus

Left ductus deferens Right ductus deferens Urinary bladder

Right seminal gland

Prostate Intermediate (membranous) urethra

Bulb Root of penis Crura

Corpus spongiosum

A. Lateral View

Body of penis Corpora cavernosa, right and left

Glans penis

Corpus cavernosum penis Intermediate (membranous) urethra Bulb of penis Crura Left crus of penis Right crus

Corpus cavernosum penis Left crus

Corpus spongiosum penis

Right crus

Corona of glans Glans penis Intermediate (membranous) urethra

Corona of glans

B. Lateral View Bulb of penis

Corpus spongiosum penis Glans penis

C. Lateral View

5.55

MALE UROGENITAL SYSTEM, ERECTILE BODIES

A. Pelvic com ponents of genital and urinary tracts and erectile bodies of perineum . B. Dissection of m ale erectile bodies (corpora cavernosa and corpus spongiosum ). C. Corpus spongiosum and corpora cavernosa, sep arated. The erectile bodies are exed

where the penis is suspended by the suspensory ligam ent of the penis from the p ubic sym p hysis. The corp us sp ongiosum extends posteriorly as the bulb of the p enis and term inates anteriorly as the glans.

MALE PERINEUM

Pe lvis an d Pe rin e um

455

DORSUM Pubic symphysis Skin Deep dorsal vein Dorsal artery Dorsal nerve

of penis

Superficial Deep Dorsal artery

Dorsal veins

Dorsal nerve

Transverse perineal ligament

Septum penis

Deep artery of penis

Deep artery

Intermediate urethra Accessory artery to bulb Bulb of penis Artery to bulb Perineal membrane Perineal membrane

Subcutaneous tissue (Colles fascia) Deep fascia

Corpus cavernosum penis and its tunica albuginea Intercavernous septum of deep fascia Corpus spongiosum penis and its tunica albuginea

Spongy (penile) urethra URETHRAL SURFACE

C. Transverse Section

A. Anterior/Inferior View Corona of glans penis

Septum penis Corpus cavernosum penis

Pubic symphysis Deep dorsal vein Dorsal nerve

of penis

Dorsal artery

Spongy (penile) urethra Corpus spongiosum penis

Ischiopubic ramus Deep artery of penis

D. Transverse Section

Intrabulbar fossa of spongy urethra Corpus spongiosum Bulb of penis

Erectile tissue of glans penis

Crus of penis

Navicular fossa (urethra)

E. Transverse Section B. Anterior View

CROSS SECTIONS OF PENIS C B A D E Lateral View

5.56

A. Transverse section through bulb of penis with crura rem oved. The bulb is cut posterior to the entry of the interm ediate urethra. On the left side, the perineal m em brane is partially rem oved, opening the deep perineal com p artm ent. B. The crura and bulb of penis have been sectioned obliquely. The spongy urethra is dilated within the bulb of the p enis. C. Transverse section through body of penis. D. Transverse section throug h the p roxim al part of the glans penis. E. Transverse section through the distal part of the glans penis.

Pe lvis an d Pe rin e um

456

Dorsal vein of penis Adductors of thigh

Bulb of penis

MALE PERINEUM Rectus abdominis

Pubic Retropubic symphysis fat

Urinary bladder

Rectovesical pouch

Sacrum

Spermatic cord Intermediate urethra entering bulb Obturator externus Superficial perineal muscles

Anal canal

Ischial tuberosity

Ischio-anal fossa Levator ani (puborectalis)

Gluteus maximus

A. Transverse

Corpus Corpus Prostate cavernosum spongiosum

Bulb of Anus penis

Rectum Coccyx

D. Median Section, Male

Section

Rectus abdominis

Pubic symphysis

Urinary bladder

Retropubic fat

Seminal gland

Rectovesical pouch Sacrum

Corpus cavernosum Crus of penis Urethra Anus Ischio-anal fossa Gluteal cleft

Adductors of thigh Obturator externus Ischiopubic ramus Sciatic nerve Ischial tuberosity Gluteus maximus

B. Transverse

Corpus Corpus Prostatic Bulb Prostate Anus spongiosum cavernosum venous of penis plexus

E. Median MRI, Prostate

MRI

F Corpus cavernosum penis

Adductors of thigh Obturator externus Ischiopubic ramus Ischial tuberosity Ischio-anal fossa Puborectalis

C. Transverse

Section

Rectum

G H

Dorsal vein of penis

ABC Urethra Crus of penis Bulb of penis

DE

Obturator internus

Sections on this page Sections on next page

Perineal body Rectum Gluteus maximus

5.57

IMAGING OF MALE PELVIS AND PERINEUM

Coccyx

MALE PERINEUM

Pe lvis an d Pe rin e um

457

Coronal MRIs: Sigmoid colon

Iliacus

Urinary bladder

External iliac artery External iliac vein

Pubic bone

Pectineus

Pubic symphysis Adductors

Corpus cavernosum penis Urethra

F.

Corpus spongiosum penis

Common iliac artery Psoas

Common iliac vein

Iliacus Sigmoid colon

Urinary blader

Head of femur Pelvic vessels and nerves

Obturator internus

Urethra Prostate

Obturator externus Urethra Corpus cavernosum penis

G. Sacrum Lumbosacral trunk

Rectum Iliacus Head of femur

Seminal gland

Obturator internus

Rectum

Obturator externus

Levator ani

Inferior rectal nerve and vessels

H.

IMAGING OF MALE PELVIS AND PERINEUM (continued )

Anus

5.57

458

Pe lvis an d Pe rin e um

FEMALE PERINEUM

Mons pubis

External pudendal vessels

Ilio-inguinal nerve External pudendal vessels

Termination of round ligament of uterus

Prepuce of clitoris Digital process of fat Glans of clitoris

Labium majus (cut surface)

Perineal branch of posterior cutaneous nerve of thigh Labium minus

Labium majus (cut surface)

Vestibule of vagina

Posterior labial vessels and nerve

Superficial perineal vessels Inferior anal (rectal) vessels Ischio-anal fossa

A. Inferior View RIGHT

LEFT

Anterior labial nerve

5.58

FEMALE PERINEUM I

A. Super cial dissection. On the right side of the specim en: • A long digital process of fat lies deep to the fatty subcutaneous tissue and descends into the labium m ajus. • The round ligam ent of the uterus ends as a branching band of fascia that spreads out sup er cial to the fatty digital process. On the left side of the specim en: • Most of the fatty d igital p rocess is rem oved. • The m ons pubis is the rounded fatty prom inence anterior to the pubic sym physis and bodies of the pubic bones. • The posterior labial vessels and nerves (S2, S3) are joined by the perineal branch of the posterior cutaneous nerve of thigh (S1, S2, S3) and run anterior to the m ons pubis. At the m ons pubis, the vessels anastom ose with the external pudendal vessels, and the nerves overlap in supply with the ilio-inguinal nerve (L1). B. Cutaneous zones of innervation.

Dorsal nerve of clitoris Posterior labial nerves Deep perineal nerve Perineal branch of posterior cutaneous nerve of thigh Inferior rectal (anal) nerve Inferior clunial nerves

B. Inferior View

FEMALE PERINEUM

Pe lvis an d Pe rin e um

459

Bulbospongiosus Ischiocavernosus Dorsal nerve of clitoris Perineal membrane Perineal branch of posterior cutaneous nerve of thigh Deep Superficial

Branches of perineal nerve

Superficial transverse perineal Dorsal nerve of clitoris Perineal nerve Pudendal nerve Inferior anal (rectal) nerve

Gluteus maximus External anal sphincter

A. Inferior View

Ilio-inguinal nerve block site Perineal branch of posterior cutaneous nerve of thigh Ischial spine (pudendal nerve block site) Sacrospinous ligament Pudendal nerve

B. Inferior View (Lithotomy Position)

INNERVATION OF THE FEMALE PERINEUM

5.59

A. Dissection of perineal nerves. The anterior aspect of the perineum is supplied by anterior labial nerves, derived from the ilio-inguinal nerve and genital branch of the genitofem oral nerve. The pudendal nerve is the m ain nerve of the perineum . Posterior lab ial nerves, derived from the super cial perineal nerve, supply m ost of the vulva. The deep perineal nerve supplies the ori ce of the vagina and super cial perineal m uscles; and the dorsal nerve of the clitoris sup plies deep p erineal m uscles and sensations to the clitoris. The inferior anal (rectal) nerve, also from the pudendal nerve, innervates the external anal sphincter and the peri-anal skin. The lateral perineum is supplied by the perineal branch of the posterior cutaneous nerve of the thigh. B. To relieve the pain experienced during childbirth, p ud e n d al n e rve b lo ck an e st h e sia m ay be perform ed by injecting a local anesthetic agent into the tissue surrounding the pudendal nerve, near the ischial spine. A pudendal nerve block does not abolish sensations from the anterior and lateral parts of the p erineum . Therefore, an an e st h e t ic b lo ck o f t h e ilio in g uin al an d / o r p e rin e al b ran ch of t h e p o st e rio r cut an e o us n e rve o f t h e t h ig h m ay also need to b e p erform ed.

460

Pe lvis an d Pe rin e um

FEMALE PERINEUM

Mons pubis and fat pad

Round ligament of uterus Digital process of fat Prepuce of clitoris Glans of clitoris

Frenulum of clitoris

Suspensory ligament of clitoris

Fascia lata

Urethral orifice Vaginal orifice

Bulbospongiosus

Ischiocavernosus Superficial transverse perineal Perineal membrane Anterior recess of ischio-anal fossa

Ischio-anal fossa

Anus Inferior View

5.60

FEMALE PERINEUM II

• Note the thickness of the subcutaneous fatty tissue of the m ons pubis and the encapsulated digital process of fat deep to this. The suspensory ligam ent of the clitoris descends from the linea alba. • Anteriorly, each labium m inus form s two lam inae or folds: The lateral lam inae of the labia p ass on each side of the glans clitoris and unite, form ing a hood that partially or com pletely covers the glans, the p repuce (foreskin) of the clitoris. The m edial lam inae of the labia m erge posterior to the glans, form ing the frenulum of the clitoris.

• There are three m uscles on each side: bulbospongiosus, ischiocavernosus, and sup er cial transverse perineal; the p erineal m em brane is visible between them . • The bulbospongiosus m uscle overlies the bulb of the vestibule and the great vestibular gland. In the m ale, the m uscles of the two sides are united by a m edian raphe; in the fem ale, the ori ce of the vagina separates the right from the left.

FEMALE PERINEUM

Pe lvis an d Pe rin e um

461

Pubic symphysis Superficial dorsal vein (reflected)

Pubic symphysis Angle

Dorsal artery of clitoris

Body of clitoris Glans

Dorsal nerve of clitoris Body of clitoris

Crus

Glans of clitoris

B

Crus of clitoris

Bulbospongiosus

Urethral orifice Perineal membrane

Bulbs of vestibule

Vaginal orifice Perineal branches of internal pudendal vessels

Duct of left greater vestibular gland Vaginal wall Levator ani

Perineal membrane

Ischial tuberosity Right greater vestibular gland and duct Bulbospongiosus

Levator ani

Anus

A. Inferior View

5.61

FEMALE PERINEUM III A. Deeper dissection. B. Clitoris. In A: • The bulbospongiosus m uscle is re ected on the right side and m ostly rem oved on the left sid e; the posterior p ortion of the bulb of the vestibule and the greater vestibular gland have been rem oved on the left sid e. • The glans and body of the clitoris is disp laced to the right so that the distribution of the dorsal vessels and nerve of the clitoris can be seen. • Hom ologues of the bulb of the p enis, the bulbs of the vestibule exist as two m asses of elongated erectile tissue that lie along the

• • In •

sides of the vaginal ori ce; veins connect the bulbs of the vestibule to the glans of the clitoris. On the specim en’s right side, the greater vestibular gland is situated at the posterior end of the bulb; both structures are covered by bulbospongiosus m uscle. On the specim en’s left side, the bulb, gland, and perineal m em brane are cut away, thereby revealing the external aspect of the vaginal wall. B: The body of the clitoris, com posed of two crura (corpora cavernosa), is capp ed by the glans.

Pe lvis an d Pe rin e um

462

FEMALE PERINEUM

Pubic symphysis

Obturator externus Clitoris (cut surface) Urethral orifice

Urethrovaginal sphincter

Ischiopubic ramus

Labium minus (cut surface)

Vaginal orifice with hymenal caruncle

Vestibule of vagina Pubovaginalis

Vaginal wall Internal pudendal vessels

Levator ani

Ischial tuberosity Perineal body

Coccygeus

Sacrotuberous ligament

External anal sphincter

Ischio-anal fossa

Anus Anococcygeal body Gluteus maximus

A. Inferior View Coccyx

Pubic symphysis

5.62

FEMALE PERINEUM IV

A. Deep perineal com partm ent. The perineal m em brane and sm ooth m uscle corresponding in position to the deep transverse p erineal m uscle in the m ale have been rem oved. • The m ost anterior and m edial p art of the levator ani m uscle, the pubovaginalis, passes posterior to the vaginal ori ce. • The urethrovaginal sp hincter, p art of the external urethral sp hincter of the fem ale, rests on the urethra and straddles the vagina. • The labia m inora (cut short here) bound the vestibule of the vagina. A. and B. The osseoligam entous boundaries of the diam ondshaped perineum are the pubic sym physis, ischiopubic ram i, ischial tuberosities, sacrotuberous ligam ents, and coccyx. For descriptive purp oses, a transverse line connecting the ischial tuberosities subdivid es the diam ond into urogenital and anal triangles.

Urethral orifice Vaginal orifice Ischial tuberosity Anus

Coccyx

B. Inferior View

Key Urogenital triangle Anal triangle

FEMALE PERINEUM

Pe lvis an d Pe rin e um

463

Digital process of fat (cut surface) Prepuce of clitoris Fascia lata covering adductor muscles of thigh

Dorsal nerve of clitoris

Crus of clitoris Bulb of vestibule (cut anterior end)

Dorsal artery of clitoris Perineal membrane (cut edge)

Smooth muscle (in female)

Internal pudendal vein Pudendal nerve Internal pudendal artery

Greater vestibular gland and duct Ischio-anal fossa Ischio-anal fat body Anus

Inferior View

FEMALE PERINEUM V This is a different dissection than the p revious series, with the vulva undissected centrally but the perineum dissected deeply on each side. Although m ost of the perineal m em brane and bulbs of the vestibule have been rem oved, the greater vestibular glands (structures of the sup er cial perineal com p artm ent) have been left in place. The developm ent and extent of the sm ooth m uscle layer corresponding in position to the voluntary deep transverse perineal m uscles of the m ale are highly variable, being relatively extensive in this case, blending centrally with voluntary bers of the external urethral sphincter and the perineal body.

5.63 The greater vestibular glands are usually not palpable but are so when infected. Occlusion of the vestibular gland duct can predispose the individual to in fe ct io n o f t h e ve st ib ular g lan d . The gland is the site or origin of m ost vulvar ad e n o carcin o m as (cancers). Bart h o lin it is, in am m ation of the greater vestibular (Bartholin) glands, m ay result from a num ber of pathogenic organism s. Infected glands m ay enlarge to a diam eter of 4 to 5 cm and im pinge on the wall of the rectum . Occlusion of the vestibular gland duct without infection can result in the accum ulation of m ucin (Bart h o lin cyst ).

Pe lvis an d Pe rin e um

464

FEMALE PERINEUM

External iliac artery External iliac vein

Myometrium

Ovary

Ovary

Femoral vein Femoral artery Adductors

Rectus abdominis

Obturator nerve and vessels

Obturator internus Endopelvic fossa

Vagina Uterus

Obturator internus

Ischio-anal fossa

Levator ani

Ilium

Rectum Gluteus maximus

Rectum

Gluteus maximus

Sacrum

Gluteal cleft

Gluteal cleft

A. Transverse MRI

B. Transverse MRI

Sacrum Fundus of uterus Ovary Ovarian follicle Broad ligament

Internal iliac artery

Lumbosacral trunk

Ovarian follicle

Sacro-iliac joint

Ovary

Internal iliac artery

Sigmoid colon

Uterus Myometrium Sigmoid colon

Internal iliac vein

Urinary bladder

Endometrium

Obturator internus

Urinary bladder

Perineal membrane

Obturator externus

Obturator internus

Urethra

Internal urethral sphincter

C. Coronal MRI

Vagina

D. Coronal MRI

A B

5.64

IMAGING OF FEMALE PELVIS AND PERINEUM

A. and B. Transverse (axial) MRIs of fem ale p elvis. C. and D. Coronal MRIs. E–H. Transverse anatom ical sections and corresponding MRIs of fem ale perineum .

CD

Pe lvis an d Pe rin e um

FEMALE PERINEUM

FA

FV MP FA FV

Ad

FA Ad Pu

OE

Pu Ur

OE

OI

OI IAF

IAF Pm

IT

IAF

R

Ad

V

V

IT

Pu

Ur

OE

OI

Sy

FV

Ad

Sy

Pu

465

OI

IAF

R LA

Pd

IT

IT

LA Max Max

Max

Max

GC

E. Anatomical Transverse Section

F. Transverse MRI Key AC Ad CC FA FV GC IAF IPR IT

Anal canal Adductor muscles Crus of clitoris Femoral artery Femoral vein Gluteal cleft Ischio-anal fossa Ischiopubic ramus Ischial tuberosity

LM

LA LM Max MP OE OI Pd Pec Pm

Levator ani Labium majus Gluteus maximus Mons pubis Obturator externus Obturator internus Pudendal canal Pectineus Perineal membrane

PR Pu QF R Sy Ur V Ve

Puborectalis Pubic bone Quadratus femoris Rectum Pubic symphysis Urethra Vagina Vestibule of the vagina

LM LM

LM Pec CC Ad

Ad

LM

LM

Pec

Ur IPR

Pm

Ad

V OI

OE

AC

QF IT

IAF

IT

IT Max

Pm

IPR

QF

PR

Ve

OE

QF IAF

Ad

IAF

AC

Max Max

Max

GC

G. Anatomical Transverse Section

IMAGING OF FEMALE PELVIS AND PERINEUM (continued )

H. Transverse MRI

5.64

Pe lvis an d Pe rin e um

466

PELVIC ANGIOGRAPHY

Bifurcation of abdominal aorta (L4 vertebral level)

Common iliac artery

Middle sacral artery

Internal iliac artery

External iliac artery

Lateral sacral arteries

Inferior gluteal artery

Superior gluteal artery

Deep circumflex iliac artery Inferior epigastric artery Obturator artery Vesical artery Obturator artery Medial circumflex femoral artery

Internal pudendal artery

Lateral circumflex femoral artery

Femoral artery Anteroposterior Radiograph

5.65

PELVIC ANGIOGRAPHY

Radiopaque dye released into the aorta of this m ale p atient entered the b ranches of the external and internal iliac arteries at the tim e this radiograph was produced.

CHAPTER 6

Lo w e r Lim b System ic Overview of Lower Lim b .....................................468 Bones ............................................................................468 Nerves ...........................................................................472 Blood Vessels .................................................................478 Lym phatics ....................................................................482 Musculofascial Com partm ents .......................................484 Retro-Inguinal Passage and Fem oral Triangle .....................486 Anterior and Medial Com partm ents of Thigh .....................490 Lateral Thigh .....................................................................497 Bones and Muscle Attachm ents of Thigh ...........................498 Gluteal Region and Posterior Com partm ent of Thigh .........500 Hip Joint ............................................................................510 Knee Region ......................................................................516 Knee Joint ..........................................................................522 Anterior and Lateral Com partm ents of Leg, Dorsum of Foot .................................................................536 Posterior Com partm ent of Leg ...........................................546 Tibio bular Joints ...............................................................556 Sole of Foot .......................................................................557 Ankle, Subtalar, and Foot Joints..........................................562 Im aging and Sectional Anatom y ........................................576

468

Lo we r Lim b

SYSTEMIC OVERVIEW OF LOWER LIMB: BONES

Iliac crest

Hip bone

Hip region Sacrum

Anterior superior iliac spine

Hip joint

Greater trochanter

Pubic symphysis

Lesser trochanter

Ischial tuberosity

Femoral region (thigh)

Femur

Knee region Patella Knee joint Popliteal region

Tibia Leg region Fibula

Ankle region Medial malleolus Ankle joint

Foot region

Calcaneus

Lateral malleolus

Key Palpable features of lower limb bones

A. Anterior View

6.1

B. Posterior View

REGIONS, BONES, AND MAJOR JOINTS OF LOWER LIMB

The hip bones m eet anteriorly at the pubic sym physis and articulate with the sacrum posteriorly. The fem ur articulates with the hip

bone proxim ally and the tibia distally. The tibia and bula are the bones of the leg that join the foot at the ankle.

SYSTEMIC OVERVIEW OF LOWER LIMB: BONES

Hip bone Iliac crest Tuberculum (tubercle) of iliac crest Anterior superior iliac spine (ASIS)

Hip bone

Iliac fossa Iliopubic eminence Superior pubic ramus

Anterior inferior iliac spine Greater trochanter

Pubic crest

Intertrochanteric line Lesser trochanter Femur

Posterior gluteal line Posterior superior iliac spine (PSIS) Posterior inferior iliac spine

Pubic tubercle

Greater sciatic notch

Pubic symphysis

Ischial spine

Body of pubis

Lesser sciatic notch

Obturator foramen Head of femur

Ischial tuberosity Acetabulum Lesser trochanter Spiral line Lateral supracondylar line

Patella

Lo we r Lim b

Iliac crest Anterior gluteal line Inferior gluteal line Ischium Head of femur Trochanteric fossa Greater trochanter Neck of femur Intertrochanteric crest Gluteal tuberosity Linea aspera

Adductor tubercle

Medial supracondylar line

Medial epicondyle

Adductor tubercle

Popliteal surface

Lateral femoral condyle

Medial femoral condyle

Medial femoral condyle

Apex of head

Medial tibial condyle Intercondylar eminence

Intercondylar fossa

Lateral femoral condyle

Tibial tuberosity

Soleal line

Anterior border Lateral surface

Vertical line

Medial surface

Tibia

Lateral epicondyle

Head Neck Fibula

Medial tibial condyle

469

Femur

Lateral tibial condyle Head Neck Fibula

Tibia

Lateral malleolus Calcaneus Cuboid

Medial malleolus

Medial malleolus

Talus

Talus

Navicular

Navicular

Cuneiforms

Medial cuneiform

First metatarsal Proximal phalanx

Calcaneus Lateral malleolus Cuboid 5th metatarsal Proximal phalanx

Distal phalanx

A. Anterior View

FEATURES OF BONES OF LOWER LIMB

B. Posterior View

6.2

The foot is in full plantar exion. The hip joint is disarticulated ( B) to dem onstrate the acetabulum of the hip bone and the entire head of the fem ur.

470

Lo we r Lim b

SYSTEMIC OVERVIEW OF LOWER LIMB: BONES

Head of femur

Ilium (I) Pubis

I

Greater trochanter

B

Ischium (S)

Femur (F)

S

Tibia

F

F Fibula

Talus Calcaneus Cuboid

C. Anteroposterior View

Metatarsals Phalanges

A. Anteroposterior View

6.3

B. Anterior View

Tibia

POSTNATAL LOWER LIMB DEVELOPMENT

A. and C. Anteroposterior radiographs of norm al postm ortem specim ens of newborns show the bony (white) and cartilaginous (gray) com ponents of the fem ur and hip bone. B. Ossi ed portions of bones of lower lim b at birth. The hip bone can be divided into three prim ary parts: ilium , ischium , and pubis. The diaphyses (bodies) of the long bones are well ossi ed. Som e epiphyses (growth plates) and tarsal bones have begun to ossify. D. Foot of child age 4. Dislo cat e d e p ip h ysis o f fe m o ral h e ad . In older children and adolescents (10 to 17 years of age), the epip hysis of the fem oral head m ay slip away from the fem oral neck because of weakness of the ep iphyseal plate. This injury m ay be caused by acute traum a or repetitive m icrotraum as that place increased shearing stress on the epiphysis, especially with abduction and lateral rotation. Fract ure s in vo lvin g e p ip h yse al p lat e s. The prim ary ossi cation center for the superior end of the tibia ap pears shortly after birth and joins the shaft of the tibia during adolescence (usually 16 to 18 years of age). Tibial fractures in children are m ore serious if they involve the epiphyseal plates because continued norm al growth of bone m ay be jeopardized. Disruption of the epiphyseal plate at the tibial tuberosity m ay cause in am m ation of the tuberosity and chronic recurring pain during adolescence (Osgood-Schlatter disease), especially in young athletes.

Epiphyseal plate Synovial fold Talus Medial cuneiform Epiphysis 1st metatarsal Proximal phalanx

Navicular Distal phalanx

D. Sagittal Section

Calcaneus

SYSTEMIC OVERVIEW OF LOWER LIMB: BONES Transverse Sections

Compact bone

Lo we r Lim b

471

Transverse Sections

Spongy bone

Tibia (T)

Spongy bone

Fibula (F) Compact bone

Compact bone T

Spongy bone

Medullary (marrow) cavity

F

T

F

Femur Fibula (F)

Tibia (T) T

F T

A. Anterior View

B. Anterior View

TRANSVERSE SECTIONS THROUGH FEMUR, TIBIA AND FIBULA A. Fem ur. B. Tibia and bula. Note the differences in thickness of the com pact and spongy bone and in the width of the m edullary (m arrow) cavity. Com pact and spongy bones are distinguished by the relative am ount of solid m atter and by the num ber and size of the spaces they contain. All bones have a super cial thin layer of com pact bone around a central m ass of spongy bone, except where

6.4

the latter is replaced by the m edullary (m arrow) cavity. Within the m edullary cavity of adult bones and between the spicules (trabeculae) of spongy bone, yellow (fatty) or red (blood cell and plateletform ing) bone m arrow or both are found. This is signi cant for MRIs where the com pact bone is seen as a thin black line surrounding the whiter spongy bone with its abundant fatty m arrow.

Lo we r Lim b

472

SYSTEMIC OVERVIEW OF LOWER LIMB: NERVES

L2 Psoas Femoral nerve (L2–L4) Iliacus

Rectus femoris Pectineus Sartorius Anterior compartment of thigh

Vastus lateralis Vastus intermedius Vastus medialis Articularis genu

L3 L4

Superior gluteal nerve Gluteal Inferior gluteal compartment nerve

Innervation of thigh: Anterior compartment Obturator nerve (L2–L4)

Medial compartment

Sciatic nerve (tibial and common fibular)

Posterior compartment

Obturator externus Posterior branch Semitendinosus

Anterior branch Adductor brevis Adductor longus Adductor magnus

Medial compartment of thigh

Posterior compartment of thigh

Biceps femoris (long head) Semitendinosus Adductor magnus

Gracilis

Semimembranosus Biceps femoris (short head)

Tibial nerve (L4–S3) Gastrocnemius

Common fibular (peroneal) nerve (L4–S2) Superficial fibular (peroneal) nerve (L4–S1) Lateral compartment of leg

Fibularis (peroneus) longus Fibularis (peroneus) brevis

Deep fibular (peroneal) nerve (L5–S2)

Posterior compartment of leg

Tibialis anterior

Popliteus

Common fibular (peroneal) nerve (L4–S2) Plantaris Gastrocnemius Soleus

Flexor digitorum longus

Tibialis posterior

Posterior compartment of leg

Extensor hallucis longus

Anterior Extensor digitorum compartment of leg longus

Flexor hallucis longus

Fibularis (peroneus) tertius

Innervation of leg: Extensor digitorum brevis

Medial plantar nerve (L4–L5)

Anterior compartment

Abductor hallucis

Lateral compartment Posterior compartment of leg and sole of foot

Flexor digitorum brevis Flexor hallucis brevis Lumbrical to 2nd digit

A. Anterior View

6.5

OVERVIEW OF MOTOR INNERVATION OF LOWER LIMB

B. Posterior View

Lateral plantar nerve (S1–S2) All other muscles in sole of foot

Lo we r Lim b

SYSTEMIC OVERVIEW OF LOWER LIMB: NERVES TABLE 6.1

473

MOTOR NERVES OF LOWER LIMB

Nerve

Origin

Femoral

Course

Distribution

Passes deep to midpoint of inguinal ligament, lateral to femoral vessels, dividing into muscular and cutaneous branches in femoral triangle

Anterior thigh muscles

Obturator

Lumbar plexus (L2–L4)

Traverses lesser pelvis to enter thigh via obturator foramen and then divides; its anterior branch descends between adductor longus and adductor brevis; its posterior branch descends between adductor brevis and adductor magnus

Anterior branch: adductor longus, adductor brevis, gracilis, and pectineus Posterior branch: obturator externus and adductor magnus

Sciatic

Sacral plexus (L4–S3)

Enters gluteal region through greater sciatic foramen, usually passing inferior to piriformis, descends in posterior compartment of thigh, bifurcating at apex of popliteal fossa into tibial and common bular (peroneal) nerves

Muscles of posterior thigh, leg and sole and dorsum of foot

Terminal branch of sciatic nerve arising at apex of popliteal fossa; descends through popliteal fossa with popliteal vessels, continuing in deep posterior compartment of leg with posterior tibial vessels; bifurcates into medial and lateral plantar nerves

Hamstring muscles of posterior compartment of thigh, muscles of posterior compartment of leg, and sole of foot

Terminal branch of sciatic nerve arising at apex of popliteal fossa; follows medial border of biceps femoris and its tendon to wind around neck of bula deep to bularis longus, where it bifurcates into super cial and deep bular nerves

Short head of biceps femoris, muscles of anterior and lateral compartments of leg, and dorsum of foot

Arises deep to bularis longus on neck of bula and descends in lateral compartment of the leg; pierces crural fascia in distal third of leg to become cutaneous

Muscles of lateral compartment of leg

Arises deep to bularis longus on neck of bula; passes through extensor digitorum longus into anterior compartment, descending on interosseous membrane; crosses ankle joint and enters dorsum of foot

Muscles of anterior compartment of leg and dorsum of foot

Tibial

Common bular (peroneal)

Sciatic nerve

Super cial bular (peroneal)

Deep bular (peroneal)

TABLE 6.2

Common bular nerve

NERVE LESIONS

Injured Nerve

Injury Description

Impa irments

Clinica l Aspects

Femoral nerve

Trauma at femoral triangle Pelvic fracture

Flexion of thigh is weakened Extension of leg is lost Sensory loss on anterior thigh and medial leg

Loss of knee jerk re ex Anesthesia on anterior thigh

Obturator nerve

Anterior hip dislocation Radical retropubic prostatectomy

Adduction of thigh is lost Variable sensory loss on medial thigh

Rare injury due to protected position

Superior gluteal nerve

Surgery Posterior hip dislocation Poliomyelitis

Gluteus medius and minimus function is lost Ability to pull contralateral pelvis up to level and abduction of thigh are lost

Supe rio r g lut e al ne rve palsy

Surgery Posterior hip dislocation

Gluteus maximus function is lost Ability to rise from a seated position, climb stairs or incline, or jump is lost

Infe rio r g lut e al ne rve palsy

Blow to lateral aspect of leg Fracture of neck of bula

Eversion of foot is lost Dorsi exion of foot is lost Extension of toes is lost Sensory loss on anterolateral leg and dorsum of foot

Co m m o n bular ne rve palsy

Trauma at popliteal fossa

Inversion of foot is weakened Plantar exion of foot is lost Sensory loss on sole of foot

Patient will present with foot dorsi exed and everted Patient cannot stand on toes

Inferior gluteal nerve

Common bular nerve

Tibial nerve at popliteal fossa

C t lt l Contralateral

Gluteus medius limp or “waddling gait” Positive Trendelenburg sign

Patient will lean the body trunk backward at heel strike

Patient will present with foot plantar exed (“footdrop”) and inverted Patient cannot stand on heels “Foot slap”

474

Lo we r Lim b

SYSTEMIC OVERVIEW OF LOWER LIMB: NERVES

Lateral cutaneous branch of subcostal nerve (T12)

Superior L1 clunial nerves L2 (posterior rami) L3

Femoral branch Genital branch

Genitofemoral nerve

Ilio-inguinal nerve Lateral cutaneous nerve of thigh, anterior branches

Lateral cutaneous branch of iliohypogastric nerve

Medial S1 clunial nerves S2 (posterior rami) S3

Lateral cutaneous nerve of thigh (posterior branches) Inferior clunial nerves (branches of posterior cutaneous nerve of thigh)

Cutaneous branch of obturator nerve Anterior cutaneous branches of femoral nerve (lateral group)

Cutaneous branches of obturator nerve

Lateral cutaneous nerve of thigh (continuation of anterior branches) Anterior cutaneous branches of femoral nerve (medial group) Posterior cutaneous nerve of thigh

Infrapatellar branch of saphenous nerve

Saphenous nerve (from femoral nerve)

Lateral sural cutaneous nerve (from common fibular nerve)

Saphenous nerve (from femoral nerve)

Lateral sural cutaneous nerve (from common fibular nerve)

Medial sural cutaneous nerve (from tibial nerve) Communicating branch of lateral sural cutaneous nerve

Superficial fibular (peroneal) nerve becoming dorsal digital nerves Sural nerve Medial calcaneal branches of tibial nerve Lateral dorsal cutaneous nerve of foot (termination of sural nerve) Deep fibular (peroneal) nerve

A. Anterior View

CUTANEOUS NERVES OF LOWER LIMB Cutaneous nerves in the subcutaneous tissue sup ply the skin of the lower lim b. In the posterior view, the m edial sural cutaneous nerve (sural is Latin for calf) is joined between the pop liteal fossa

Medial plantar nerve (from tibial nerve)

Lateral plantar nerve (from tibial nerve)

B. Posterior View

6.6 and posterior aspect of the ankle by a com m unicating branch of the lateral sural cutaneous nerve to form the sural nerve. The level of the junction is variable and is low in this specim en.

SYSTEMIC OVERVIEW OF LOWER LIMB: NERVES

TABLE 6.3

Lo we r Lim b

475

CUTANEOUS NERVES OF LOWER LIMB

Nerve

Origin (Contributing Spina l Nerves)

Course

Distribution to Skin of Lower Limb

Subcostal (lateral cutaneous branch)

T12 anterior ramus

Descends over iliac crest

Hip region inferior to anterior part of iliac crest and anterior to greater trochanter

Iliohypogastric

Lumbar plexus (L1; occasionally T12)

Parallels iliac crest

Lateral cutaneous branch supplies superolateral quadrant of buttock

Ilio-inguinal

Lumbar plexus (L1; occasionally T12)

Passes through inguinal canal

Inguinal fold; femoral branch supplies skin over medial femoral triangle

Genitofemoral

Lumbar plexus (L1–L2)

Descends anterior surface of psoas major

Femoral branch supplies skin over lateral part of femoral triangle; genital branch supplies anterior scrotum or labia majora

Lateral cutaneous nerve of thigh

Lumbar plexus (L2–L3)

Passes deep to inguinal ligament, 1 cm medial to anterior superior iliac spine

Skin on anterior and lateral aspects of thigh

Anterior cutaneous branches

Lumbar plexus via femoral nerve (L2–L4)

Arise in femoral triangle; pierce fascia lata along the path of sartorius muscle

Skin of anterior and medial aspects of thigh

Cutaneous branch of obturator nerve

Lumbar plexus via obturator nerve (L2–L4)

Following its descent between adductors longus and brevis, obturator nerve pierces fascia lata to reach the skin of thigh

Skin of middle part of medial thigh

Posterior cutaneous nerve of thigh

Sacral plexus (S1–S3)

Enters gluteal region via greater sciatic foramen deep to gluteus maximus; then descends deep to fascia lata; terminal branches pierce fascia lata

Skin of posterior thigh and popliteal fossa

Saphenous nerve

Lumbar plexus via femoral nerve (L3–L4)

Traverses adductor canal but does not pass through adductor hiatus

Skin on medial side of leg and foot

Super cial bular nerve

Common bular nerve (L4–S1)

After supplying bular muscles, perforates deep fascia of leg

Skin of anterolateral leg and dorsum of foot

Deep bular nerve

Common bular nerve (L5)

After supplying muscles on dorsum of foot, pierces deep fascia superior to heads of 1st and 2nd metatarsals

Skin of web between great and 2nd toes

Sural nerve

Tibial and common bular nerves (S1–S2)

Medial sural cutaneous branch of tibial nerve and lateral sural cutaneous branch of common bular nerve merge at varying levels on posterior leg

Skin of posterolateral leg and lateral margin of foot

Medial plantar nerve

Tibial nerve (L4–L5)

Passes between rst and second layers of plantar muscles

Skin of medial side of sole, and plantar aspect, sides, and nail beds of medial 3½ toes

Lateral plantar nerve

Tibial nerve (S1–S2)

Passes between rst and second layers of plantar muscles

Skin of lateral sole, and plantar aspect, sides, and nail beds of lateral 1½ toes

Calcaneal nerves

Tibial and sural nerves (S1–S2)

Branches over calcaneal tuberosity

Skin of heel

Superior clunial nerves

L1–L3 posterior rami

Course laterally/inferiorly in subcutaneous tissue

Skin overlying superior and central parts of buttock

Medial clunial nerves

S1–S3 posterior rami

From dorsal sacral foramina; enter overlying subcutaneous tissue

Skin of medial buttock and intergluteal cleft

Inferior clunial nerves

Posterior cutaneous nerve of thigh (S2–S3)

Arise deep to gluteus maximus; emerge from beneath inferior border of muscle

Skin of inferior buttock (overlying gluteal fold)

Lo we r Lim b

476

SYSTEMIC OVERVIEW OF LOWER LIMB: NERVES

Medial internal rotation (hip) L4 L5

Lateral external rotation (hip) L5 S1

Inversion L4 L5

Eversion L5 S1 Extension (hip) L4 L5

Subtalar Inversion and Eversion

Flexion (hip) L2 L3

Anterior View 40º

50º



Adduction (hip) L1 L2 L3 L4

Dorsiflexion Extension (toes) L5 S1

Abduction (hip)

S1 S2 S2 S3

L5 S1

Flexion (knee) L5 S1

Plantarflexion Flexion (toes) Metatarsophalangeal and phalangeal Lateral View

Medial View

Anterior View

Extension (knee) L3 L4 Dorsiflexion (ankle) L4 L5 Plantarflexion S1 (ankle) S2

A

B

6.7

Myotatic (Deep Tendon) Reflex

Spinal Cord Segments

Quadriceps (knee jerk)

L3/L4

Calcaneal (Achilles; ankle jerk)

S1/S2

MYOTOMES AND DEEP TENDON REFLEXES

A. Myotom es. Som atic m otor (general som atic efferent) bers transm it im pulses to skeletal (voluntary) m uscles. The unilateral m uscle m ass receiving innervation from the som atic m otor bers conveyed by a single spinal nerve is a m yotom e. Each skeletal m uscle is usually innervated by the som atic m otor bers of several spinal nerves; therefore, the m uscle m yotom e will consist of several segm ents. The m uscle m yotom es have been grouped by joint m ovem ent to

TABLE 6.4

facilitate clinical testing. B. Myotatic (deep tendon) re exes. A m yotatic (stretch) re ex is an involuntary contraction of a m uscle in response to being stretched. Deep tendon re exes (e.g., “knee jerk”) are m onosynaptic stretch re exes that are elicited by briskly tapping the tendon with a re ex ham m er. Each tendon re ex is m ediated by speci c spinal nerves. Stretch re exes control m uscle tone (e.g., in antigravity, m uscles that keep the body upright against gravity).

NERVE ROOT ( ANTERIOR RAMUS) LESIONS

Compressed Nerve Root

Derma tome Affected

Muscles Affected

Movement Wea kness/De cit

Nerve a nd Re ex Involved

L4

L4: medial surface of leg; big toe

Quadriceps

Extension of knee

Femoral nerve ↓ Knee jerk

L5

L5: lateral surface of leg; dorsum of foot

Tibialis anterior Extensor hallucis longus Extensor digitorum longus

Dorsi exion of ankle (patient cannot stand on heels) Extension of toes

Common bular nerve No re ex loss

S1

S1: posterior surface of lower limb; little toe

Gastrocnemius Soleus

Plantar exion of ankle (patient cannot stand on toes) Flexion of toes

Tibial nerve ↓ Ankle jerk

SYSTEMIC OVERVIEW OF LOWER LIMB: NERVES

T10

Lo we r Lim b

477

L3 L4 L5 S1

T10

S2

T11

T11

T12 L2

L1

T12

C1 S3

S4

S5

S3 S4 S5

S2

S3

L1

S2

L5

C1

S3

S4 L2

L1

L2

L3 L2

L3

S2

L3

Axial line Axial line

S2 S1 L3

L5 L4

L5

L4

L4

L5

L4 S2 S1

S1 S2

S1 S1

L5

A. Anterior View

B. Posterior View

DERMATOMES OF LOWER LIMB The dermatomal, or segmental, pattern of distribution of sensory nerve bers persists despite the merging of spinal nerves in plexus formation during development. Two different dermatome maps are commonly used. A. and B. The dermatome pattern of the lower limb according to Foerster (1933) is preferred by many because of its

L4 L5

C. Anterior View

D. Posterior View

6.8 correlation with clinical ndings. C. and D. The dermatome pattern of the lower limb according to Keegan and Garrett (1948) is preferred by others for its aesthetic uniformity and obvious correlation with development. Although depicted as distinct zones, adjacent dermatomes overlap considerably, except along the axial line.

478

Lo we r Lim b

External iliac artery

SYSTEMIC OVERVIEW OF LOWER LIMB: BLOOD VESSELS

Aorta Common iliac artery

Deep circumflex iliac artery

Internal iliac artery Inferior epigastric artery

Superficial circumflex iliac artery Profunda femoris artery (deep artery of thigh)

Lateral circumflex femoral artery Perforating arteries

Obturator artery Medial circumflex femoral artery

Descending genicular artery

Superior lateral genicular artery

Inferior gluteal artery

Cruciate anastomosis

External pudendal artery

Femoral artery

Descending branch

Superior gluteal artery

Popliteal artery Superior medial genicular artery

Medial circumflex femoral artery

Lateral circumflex femoral artery

Profunda femoris artery (deep artery of thigh) Perforating arteries Femoral artery

Hiatus in adductor magnus Geniculate anastomosis Superior medial genicular artery Superior lateral genicular artery Popliteal artery

Inferior lateral genicular artery Inferior medial genicular artery

Inferior medial genicular artery

Inferior lateral genicular artery

Geniculate anastomosis Anterior tibial artery

Anterior tibial recurrent artery

Fibular (peroneal) artery Anterior tibial artery

Posterior tibial artery

Perforating branch of fibular (peroneal) artery Lateral malleolar artery

Perforating branch Tarsal anastomosis Medial malleolar artery

Lateral tarsal artery Arcuate artery Dorsal digital arteries

Dorsalis pedis artery (dorsal artery of foot) Medial tarsal artery Deep plantar artery 1st dorsal metatarsal artery

A. Anterior View

6.9

Tarsal anastomosis Medial plantar artery Lateral plantar artery Plantar arch Deep plantar artery

B. Posterior View

Plantar metatarsal artery Plantar digital arteries

OVERVIEW OF ARTERIES OF LOWER LIMB

The arteries often anastom ose or com m unicate to form networks to ensure blood sup ply distal to the joint throug hout the range of m ovem ent (cruciate, geniculate and tarsal anastom oses).

If a m ain channel is slowly occluded, the sm aller alternate channels can usually increase in size, providing a co llat e ral circulat io n that ensures the blood supply to structures distal to the blockage.

Lo we r Lim b

SYSTEMIC OVERVIEW OF LOWER LIMB: BLOOD VESSELS

479

Inferior vena cava External iliac vein Common iliac vein

Deep circumflex iliac vein

Internal iliac vein Inferior epigastric vein Obturator vein

Medial circumflex femoral vein

Superior gluteal vein Internal pudendal vein Inferior gluteal vein

Lateral circumflex femoral vein Profunda femoris vein (deep vein of thigh)

Great saphenous vein Femoral vein Perforating veins

Descending genicular vein

Lateral superior genicular vein

Profunda femoris vein (deep vein of thigh) Femoral vein

Descending genicular vein

Lateral superior genicular vein

Medial superior genicular vein Popliteal vein

Lateral inferior genicular vein Medial inferior genicular vein

Medial inferior genicular vein

Lateral inferior genicular vein Circumflex fibular vein

Anterior tibial veins Posterior tibial veins

Fibular (peroneal) vein

Plantar venous arch Dorsal venous arch

Plantar digital veins

A. Anterior View

B. Posterior View

Accompanying veins (L. venae comitantes)

Artery

C.

Vascular sheath

DEEP VEINS OF LOWER LIMB

6.10

A. and B. Deep veins lie internal to the deep fascia. Although only the anterior and posterior tibial veins are depicted as paired structures in this schem atic illustration, typically in the lim bs deep veins occur as multiple, generally parallel, continually interanastomosing accompanying veins (L. venae comitantes) surrounding and sharing the name of the artery they accompany. C. Accom panying veins.

Lo we r Lim b

480

SYSTEMIC OVERVIEW OF LOWER LIMB: BLOOD VESSELS

Superficial circumflex iliac vein Superficial epigastric vein Femoral vein Superficial external pudendal vein

Great saphenous vein

Key Sites where perforating veins penetrate deep fascia Small saphenous vein

Great saphenous vein Lateral cutaneous vein of thigh

Small (short) saphenous vein Medial cutaneous vein of thigh Small saphenous vein Lateral malleolus

Dorsal venous arch Common dorsal digital veins

B. Posterior View

C. Lateral View

Great saphenous vein Medial malleolus Site of saphenous cutdown

A. Anteromedial View

6.11

SUPERFICIAL VEINS OF LOWER LIMB

Highly anastom otic veins, largely unaccom panied by arteries, are abundant in the subcutaneous tissue, draining deeply via m ultiple perforating veins. Ve in g raft s obtained by surgically harvesting parts of the great saphenous vein are used to bypass ob structions in blood vessels (e.g., a coronary artery). When used as a bypass, the vein is reversed so that the valves do not obstruct b lood ow. Because there are so m any anastom osing leg veins, rem oval of the g reat saphenous vein rarely affects circulation seriously, provided the deep veins are intact. Sap h e n o us cut d o wn . The great saphenous vein can be located by m aking a skin incision anterior to the m edial m alleolus. This p rocedure is used to insert a cannula for prolonged adm inistration of blood, electrolytes, drugs, etc.

SYSTEMIC OVERVIEW OF LOWER LIMB: BLOOD VESSELS

Great saphenous vein

Lo we r Lim b

481

Patella

Popliteal vein Great saphenous vein Deep veins

Posterior tibial vein

Perforating veins

Fibular vein

Medial malleolus

Dorsal venous arch

Patella

Plantar vein

A. Medial View

Great saphenous vein

Great saphenous vein Medial malleolus Dorsal venous arch

B. Medial View, Varicose Veins

C. Anteromedial View, Normal Veins

DRAINAGE AND SURFACE ANATOMY OF SUPERFICIAL VEINS OF LOWER LIMB A. Schem atic diagram of drainage of super cial veins. Blood is shunted from the super cial veins (e.g., great saphenous vein) to the deep veins (e.g., bular and posterior tibial veins) via perforating veins that penetrate the deep fascia. Muscular com pression of deep veins assists return of blood to the heart against gravity. B. Varicose

6.12

veins form when either the deep fascia or the valves of the perforating veins are incom petent. This allows the m uscular com pression that norm ally propels blood toward the heart to push blood from the deep to the super cial veins. Consequently, super cial veins become enlarged and tortuous. C. Norm al veins distended following exercise.

Lo we r Lim b

482

Superficial inguinal lymph nodes (1) (superior group) Deep inguinal lymph nodes (2)

SYSTEMIC OVERVIEW OF LOWER LIMB: LYMPHATICS

Femoral vein (5) Saphenous opening (6)

1

Superficial inguinal lymph nodes (3) (inferior group)

5 4

2 Great saphenous vein (4)

3

6

B. Anteromedial View Popliteal vein

Popliteal lymph nodes (superficial nodes)

Small saphenous vein

Medial malleolus Dorsal digital vein of great toe

A. Anteromedial View

6.13

C.

Posterior View

SUPERFICIAL LYMPHATIC DRAINAGE OF LOWER LIMB

The super cial lym p hatic vessels accom pany the saphenous veins and their tributaries in the sup er cial fascia. The lym p hatic vessels along the great sap henous vein drain into the super cial inguinal lym ph nodes; those along the sm all saphenous vein drain into the popliteal lym ph nodes. Lym ph from the super cial inguinal nodes drains to the deep inguinal and external iliac nodes. Lym ph from the p opliteal nodes ascends throug h deep lym phatic vessels accom panying the deep blood vessels to the deep inguinal nodes.

Note that the great saphenous vein lies anterior to the m edial m alleolus and a hand’s bread th posterior to the m edial border of the patella. Lym p h n o d e s e n larg e when diseased. Abrasions and m inor sepsis, caused by pathogenic m icro-organism s or their toxins, m ay produce slight enlargem ent of the super cial inguinal nodes (lym phadenopathy) in otherwise healthy people. Malignancies (e.g., of the external genitalia and uterus) and p erineal abscesses also result in enlargem ent of these nodes.

SYSTEMIC OVERVIEW OF LOWER LIMB: LYMPHATICS

Lo we r Lim b

483

Superficial inguinal lymph nodes (superolateral nodes) Inguinal ligament

Superficial inguinal lymph nodes (superomedial nodes)

Spermatic cord

Deep inguinal node Superficial inguinal lymph nodes (inferior nodes)

Great saphenous vein Superficial lymphatic vessels

A. Anterior View

External iliac nodes

Lymphatic vessels

Inguinal lymph nodes

B. Anteroposterior Lymphangiogram

INGUINAL LYMPH NODES A. Dissection. B. Lym phangiogram . • Ob serve th e arran g em en t of th e nod es: a proxim al chain parallel to the inguinal ligament (superolateral and superom edial supercial inguinal lymph nodes) and a distal chain on the sides of the

6.14 great saphenous vein (inferior super cial inguinal lym ph nodes). Efferent vessels leave these nodes and pass deep to the inguinal ligam ent to enter the deep inguinal and external iliac nodes. • Note the anastom osis between the lym ph vessels.

484

Lo we r Lim b

SYSTEMIC OVERVIEW OF LOWER LIMB: MUSCULOFASCIAL COMPARTMENTS

Iliac crest Anterior superior iliac spine

Iliac tubercle

Inguinal ligament

Saphenous opening

Falciform margin of saphenous opening

Tensor fasciae latae

Pubic tubercle

Great saphenous vein

Cribriform fascia in saphenous opening

Subcutaneous tissue Fascia lata

Level of section in Figure 6.15C Iliotibial tract

Gluteus maximus Ischial tuberosity (deep to muscle when thigh is extended)

Iliotibial tract

Fascia lata

Bursae

Deep fascia of leg (crural fascia)

Patella Level of section in Figure 6.15D

Tibia

Anterolateral tibial (Gerdy) tubercle

B. Lateral View

Extensor retinacula

A. Anterior View

6.15

FASCIA AND MUSCULOFASCIAL COMPARTMENTS OF LOWER LIMB

A. Anterior skin and subcutaneous tissue have been rem oved to reveal the deep fascia of the thigh (fascia lata) and leg (crural fascia). B. Lateral skin and subcutaneous tissue have been rem oved to reveal the fascia lata. The fascia lata is thick laterally and form s the iliotibial tract. The iliotibial tract serves as a com m on aponeurosis for the gluteus m axim us and tensor fasciae latae m uscles. One of the m ost com m on causes of lateral knee p ain in endurance athletes

(e.g., runners, cyclers, hikers) is ilio t ib ial t ract (b an d ) syn d ro m e (ITBS). Friction of the IT tract against the lateral epicondyle of the fem ur with exion and extension of the knee (e.g., during running) m ay result in the in am m ation of the IT tract over the lateral aspect of the knee or its attachm ent to the dorsolateral tubercle (Gerdy tubercle). ITBS m ay also occur in the hip region, especially in older individuals.

SYSTEMIC OVERVIEW OF LOWER LIMB: MUSCULOFASCIAL COMPARTMENTS

Lo we r Lim b

Posterior compartment of thigh (P) (flexor muscles of knee)

Investing fascia

POSTERIOR

Subcutaneous tissue Lateral femoral intermuscular septum

LATERAL P

P

ANTERIOR P

Posteromedial femoral intermuscular septum

M

Iliotibial tract A

M A

A

A

Anterior compartment of thigh (A) (extensor muscles of knee)

MEDIAL

P

A

Femur

485

Medial compartment of thigh (M) (adductor muscles of hip) Anteromedial femoral intermuscular septum Fascia lata

C. Anterosuperior View

Deep fascia of leg (outer, circumferential layer)

Transverse intermuscular septum SP

Posterior intermuscular septum of leg

SP SP

Fibula Deep fascia of tibialis posterior Lateral compartment of leg (L) (evertor muscles)

Anterior intermuscular septum of leg Interosseous membrane

BF

DP

L

L

A

DP

DP

C

Superficial part of posterior compartment of leg (SP) (plantar flexor muscles) Deep part of posterior compartment of leg (DP) (long flexor of digits and invertor muscles of foot)

D

Tibia

A A

Anterior compartment of leg (A) (dorsiflexor, invertor of foot and long extensor muscles of digits)

Deep fascia blended with periosteum of bone Investing fascia Subcutaneous tissue

D. Anterosuperior View

FASCIA AND MUSCULOFASCIAL COMPARTMENTS OF LOWER LIMB (continued ) C. and D. The fascial compartments of the thigh (C) and leg (D) are demonstrated in transverse section. The fascial compartments contain muscles that generally perform common functions and share common innervation and contain the spread of infection. While both thigh and leg have anterior and posterior compartments, the thigh also includes a medial compartment and the leg a lateral compartment. Trauma to muscles and/or vessels in the compartments may produce hemorrhage, edema, and in ammation of the muscles. Because the septa,

6.15

deep fascia, and bony attachments rmly bound the compartments, increased volume resulting from these processes raises intracompartmental pressure. In com p artm en t syn d rom es, structures within or distal to the compressed area become ischemic and may become permanently injured (e.g., compression of capillary beds results in denervation and consequent paralysis of muscles). A fasciotom y (incision of bounding fascia or septum) may be performed to relieve the pressure in the compartment and restore circulation.

486

Lo we r Lim b

RETRO-INGUINAL PASSAGE AND FEMORAL TRIANGLE

Superficial circumflex iliac artery and vein

Subcutaneous tissue (superficial fascia)

Superficial epigastric artery and vein Superficial external pudendal artery and vein

Femoral sheath Inguinal ligament Ilio-inguinal nerve

A

Fascia lata

Great saphenous vein

Edge of saphenous opening SUPERIOR

Valve cusp Femoral vein Cribriform fascia Femoral artery Edge of saphenous opening LATERAL

MEDIAL

Superficial epigastric artery Great saphenous vein Femoral branch of genitofemoral nerve

Great saphenous vein Fascia lata (deep fascia of thigh)

Superficial inguinal nodes

INFERIOR

B

6.16

C

SUPERFICIAL INGUINAL VESSELS AND SAPHENOUS OPENING

A. Super cial inguinal vessels. The arteries are branches of the fem oral artery, and the veins are tributaries of the great saphenous

vein. B. Valves of the proxim al p art of fem oral and great sap henous veins. C. Saphenous op ening.

Lo we r Lim b

RETRO-INGUINAL PASSAGE AND FEMORAL TRIANGLE

487

Psoas fascia Iliac fascia Genitofemoral nerve External iliac artery

Anterior superior iliac spine

External iliac vein Psoas

Iliacus Lateral cutaneous nerve of thigh

Femoral nerve

Sartorius

Deep circumflex iliac artery

Inguinal ligament

Transversalis fascia Inferior epigastric artery

Iliac fascia Femoral nerve Lateral border of saphenous opening

Artery and nerve to cremaster Lymph vessels

Femoral sheath Fascia lata

Great saphenous vein

A Femoral nerve Iliacus muscle Psoas major tendon Anterior superior iliac spine Iliacus fascia

Superficial circumflex iliac artery

Iliopsoas

Psoas minor tendon

Inguinal ligament Femoral sheath

Iliopectineal arch Femoral vein

Inguinal ligament Femoral artery

Deep inguinal lymph node (Cloquet node)

Lacunar ligament Lymph node in femoral canal

Superficial epigastric artery

Pectineal fascia

Femoral canal

External spermatic fascia

Pectineal ligament Femoral septa

Femoral ring Lacunar ligament

External pudendal artery

Great saphenous vein

Femoral sheath Deep inguinal lymph node Fascia lata

Pectineus Saphenous opening

C

Great saphenous vein Key

B

Outline of femoral triangle

FEMORAL SHEATH AND INGUINAL LIGAMENT A. Dissection . B. Sch em atic illustration . Th e fem oral sh eath con tain s th e fem oral artery, vein , an d lym p h vessels, b ut th e fem oral n erve, lyin g p osterior to th e iliacus fascia, is outsid e th e fem oral sh eath . C. Fem oral sh eath an d fem oral rin g . Th e th ree

Anterior Views

6.17 com p artm en ts of th e fem oral sh eath are for th e fem oral artery, vein , an d fem oral can al. Th e fem oral can al h as a sm all p roxim al op en in g at its ab d om in al en d , th e fem oral rin g , closed b y extrap eriton eal fatty tissue.

Lo we r Lim b

488

RETRO-INGUINAL PASSAGE AND FEMORAL TRIANGLE Anterior superior iliac spine

Compartments:

Aponeurosis of external oblique

Retro-inguinal space Muscular compartment Vascular compartment

Superficial inguinal ring Medial crus

Inguinal ligament Femoral artery and vein Anterior inferior iliac spine Groove for psoas tendon Iliopubic eminence

Anterior superior iliac spine

Acetabulum Inguinal ligament

Outline of femoral triangle (black line) Lateral cutaneous nerve of thigh Superficial circumflex iliac artery

Iliopsoas Pectineal ligament

Deep circumflex iliac artery

Femoral ring

Lacunar ligament

Pectineus Pubic tubercle

Profunda femoris artery

Anterior superior iliac spine Inguinal ligament Nerve Artery Vein

Obturator nerve, anterior branch

Superficial inguinal ring (site of inguinal hernia)

Iliopsoas

Gracilis

Lacunar ligament Plane of Figure 6.19B

Rectus femoris

Pubic tubercle

Great saphenous vein

Pectineus Obturator canal (site of obturator hernia)

Iliotibial tract Anterior cutaneous nerves of thigh

A. Anterior View

6.18

Femoral

Femoral ring (site of femoral hernia)

1st perforating artery Adductor longus

Sartorius

Pubic tubercle

Lacunar ligament

Nerve Femoral Artery Vein

Iliotibial tract

B. Anterior View

Femoral ring

Lateral crus

Pectineus

Obturator membrane

C. Anterior View

STRUCTURES PASSING TO/ FROM FEMORAL TRIANGLE VIA RETRO-INGUINAL PASSAGE

A. Dissection. The boundaries of the fem oral triangle are the inguinal ligam ent superiorly (base of triangle), the m edial border of the sartorius (lateral side), and the lateral border of the ad ductor longus (m edial side). The point at which the lateral and m edial sides converge inferiorly form s the apex. The fem oral triangle is bisected by the fem oral vessels. B. Retro-inguinal p assage between the inguinal ligam ent anteriorly and the bony p elvis posteriorly.

C. The iliopsoas m uscle, the fem oral nerve, artery, and vein, and the lym phatic vessels draining the inguinal nodes pass deep to the inguinal ligam ent to enter the anterior thigh or return to the trunk. Three potential sites for h e rn ia fo rm at io n are indicated. Pulsat io n s o f t h e fe m o ral art e ry can b e felt distal to the inguinal ligam ent, m id way between the anterior sup erior iliac spine and the pub ic tubercle.

Lo we r Lim b

RETRO-INGUINAL PASSAGE AND FEMORAL TRIANGLE

POSTERIOR Iliopectineal bursa

489

Extension of iliopectineal arch

Head of femur Ilium Iliopsoas

Pectineus

LATERAL

MEDIAL Pectineal fascia Lacunar ligament

Femoral nerve Iliac fascia

Lymph node in femoral canal

Anterior superior iliac spine Sartorius Tensor fasciae latae Iliotibial tract

Inguinal ligament

Femoral sheath Femoral vein

ANTERIOR

Femoral artery

B. Superior View

Nerve Artery Femoral Vein

Iliacus

Anterior superior iliac spine Superficial inguinal ring

Psoas

Inguinal ligament Femoral nerve

Medial circumflex femoral artery and vein Lateral circumflex femoral artery

Pectineus

Profunda femoris artery and vein

Adductor longus

Nerve to vastus medialis Neurovascular bundle within adductor canal

Femoral artery Femoral vein Pubic tubercle Adductor longus

Femoral artery and vein

Apex of femoral triangle

Saphenous nerve Gracilis

Adductor canal

Rectus femoris Sartorius

Sartorius Femur

Vastus lateralis

Adductor hiatus Adductor tubercle

A. Anterior View

C. Anterior View

FLOOR OF FEMORAL CANAL AND RETRO-INGUINAL PASSAGE A. Dissection. Portions of the sartorius m uscle, fem oral vessels, and fem oral nerve have been rem oved revealing the oor of the fem oral triangle, form ed by the iliopsoas laterally and the pectineus m edially. At the apex of the triangle, the fem oral vessels, saphenous nerve, and the nerve to the vastus m edialis pass deep to the sartorius into the adductor (subsartorial) canal. B. Transverse section of the fem oral triangle at the level of head of fem ur. The iliopsoas

6.19

and fem oral nerve traverse the retro-inguinal passage and fem oral triangle in a fascial sheath separate from the fem oral vessels, which are contained within the fem oral sheath (see Fig. 6.18C for level of section). C. Schem atic illustration of course of fem oral vessels. The adductor canal extends from the apex of the fem oral triangle to the adductor hiatus by which the vessels enter and leave the popliteal fossa.

Lo we r Lim b

490

ANTERIOR AND MEDIAL COMPARTMENTS OF THIGH

Sartorius

Rectus femoris

Vastus intermedius

Adductor longus

Vastus lateralis

Vastus medialis

Patella

Patellar ligament

A. Anterior View

6.20

B. Anteromedial View

SURFACE ANATOMY OF ANTERIOR AND MEDIAL ASPECTS OF THIGH

Pat e llar t e n d in it is (jum p er’s knee) is caused by continuous overloading of the knee extensor m echanism , resulting in m icrotears of the tendon. The m ost vulnerable site is where the patellar ligam ent

(tendon) attaches to the patella. This overuse injury can result in degeneration and tearing of the tendon.

ANTERIOR AND MEDIAL COMPARTMENTS OF THIGH

Lo we r Lim b

491

Tendon of psoas minor Iliacus

Iliacus Anterior superior iliac spine

Psoas major

Psoas major Tensor fasciae latae

Fascia lata Tensor fasciae latae

Pubic tubercle Pectineus

Rectus femoris (proximal end) Adductor longus (proximal end)

Gluteus minimus

Adductor brevis Pectineus (distal end)

Sartorius Adductor longus

Adductor longus (distal end)

Iliotibial tract Rectus femoris Gracilis

Gracilis Vastus intermedius

Adductor magnus

Iliotibial tract

Vastus lateralis

Vastus lateralis

Vastus medialis

Vastus medialis

Patella Lateral patellar retinaculum

Tibial tuberosity

Sartorius (distal end)

Rectus femoris (distal end)

Medial meniscus

Medial patellar retinaculum

Sartorius tendon Patellar ligament

Gracilis tendon

Sartorius

B

A

Tibia

Anterior Views

ANTERIOR AND MEDIAL THIGH MUSCLES, SUPERFICIAL AND DEEP DISSECTIONS A. Super cial dissection. B. Deep dissection. The central portions of the m uscle bellies of the sartorius, rectus fem oris, pectineus, and adductor longus m uscles have b een rem oved. We akn e ss o f

6.21

t h e vast us m e d ialis o r vast us lat e ralis, resulting from arthritis or traum a to the knee joint, for exam ple, can result in abnorm al patellar m ovem ent and loss of joint stability.

Lo we r Lim b

492

ANTERIOR AND MEDIAL COMPARTMENTS OF THIGH

Iliopsoas

Femoral artery, vein, and nerve

Anterior superior iliac spine

Tensor fasciae latae Pectineus

Pectineus

Sartorius

Adductor brevis

Rectus femoris

Adductor longus

Gracilis Adductor longus Vastus lateralis

Vastus intermedius Rectus femoris

Iliotibial tract

Attachments cut: Vastus lateralis

Vastus lateralis Vastus medialis

Vastus medialis Vastus medialis

Patella

Rectus femoris

Quadriceps tendon Patellar ligament

Sartorius attachment

Gracilis attachment

Gracilis

A

B

C

D

Anterior Views

6.22

ANTERIOR AND MEDICAL THIGH MUSCLES, SCHEMATIC ILLUSTRATIONS

A–D. Seq uential views from super cial to deep. A “hip pointer,” which is a co n t usio n o f t h e iliac cre st , usually occurs at its anterior part (e.g., where the sartorius attaches to the anterior sup erior iliac sp ine). This is one of the m ost com m on injuries to the hip region, usually occurring in association with collision sports. Contusions cause bleeding from ruptured capillaries and in ltration of blood into the m uscles, tendons, and other soft tissues. The term hip pointer m ay also refer to avulsion of b ony

m uscle attachm ents, for exam ple, of the sartorius or rectus fem oris from the anterior sup erior or inferior iliac spines or of the iliop soas from the lesser trochanter of the fem ur. However, these injuries should b e called avulsio n fract ure s. A p erson with a p a ra lyze d q u a d rice p s can n ot exten d th e leg ag ain st resistan ce an d usually p resses on th e d istal en d of th e th ig h d urin g walkin g to p reven t in ad verten t exion of th e kn ee join t.

ANTERIOR AND MEDIAL COMPARTMENTS OF THIGH

Lo we r Lim b

493

Psoas major 12th rib

Tensor fasciae latae Sartorius

Iliacus

Psoas minor

Rectus femoris

Sartorius Psoas major

Rectus femoris

Iliacus

Vastus lateralis Vastus medialis

Iliopectineal arch Iliopsoas

Vastus lateralis

Vastus lateralis

Pectineus Iliopsoas

Vastus intermedius

Vastus medialis

Vastus intermedius

Vastus medialis

Linea aspera

Articularis genu

Vastus lateralis

E

H Anterior Views

Posterior Views Patellar ligament

F

G

6.22

ANTERIOR AND MEDICAL THIGH MUSCLES, SCHEMATIC ILLUSTRATIONS (continued ) E. Iliopsoas. F. and G. Attachm ents of anterior m uscles of thigh. H. Posterior attachm ent of vastus m ed ialis and lateralis.

TABLE 6.5

MUSCLES OF ANTERIOR THIGH Proxima l Atta chment a

Dista l Atta chment a

Innerva tion b

Lateral aspects of T12–L5 vertebrae and intervertebral discs; transverse processes of all lumbar vertebrae

Lesser trochanter of femur

Anterior rami of lumbar nerves (L1 , L2 , and L3)

Iliacus

Iliac crest, iliac fossa, ala of sacrum and anterior sacro-iliac ligaments

Tendon of psoas major, lesser trochanter, and femur distal to it

Femoral nerve (L2 and L3)

Tensor fasciae latae

Anterior superior iliac spine and anterior part of iliac crest

Iliotibial tract that attaches to lateral condyle of tibia

Superior gluteal (L4 and L5)

Abducts, medially rotates, and exes hip joint; helps to keep knee extended; steadies trunk on thigh

Sartorius

Anterior superior iliac spine and superior part of notch inferior to it

Superior part of medial surface of tibia

Femoral nerve (L2 and L3)

Flexes, abducts, and laterally rotates hip joint; exes knee joint d

Muscle Ilio pso as Psoas major

Quadrice ps fe m o ris Rectus femoris Vastus lateralis

a

Anterior inferior iliac spine and ilium superior to acetabulum Greater trochanter and lateral lip of linea aspera of femur

Vastus medialis

Intertrochanteric line and medial lip of linea aspera of femur

Vastus intermedius

Anterior and lateral surfaces of body of femur

Base of patella and by patellar ligament to tibial tuberosity; medial and lateral vasti also attach to tibia and patella via aponeuroses (medial and lateral patellar retinacula)

Femoral nerve (L2, L3 , and L4 )

Ma in Actions

Flexes and stabilizesc hip joint

Extends knee joint; rectus femoris also steadies hip joint and helps iliopsoas to ex hip joint

See also Figure 6.22 for muscle attachments. Numbers indicate spinal cord segmental innervation of nerves (e.g., L1, L2, and L3 indicate that nerves supplying psoas major are derived from rst three lumbar segments of the spinal cord; boldface type [e.g., L1 , L2 ] indicates main segmental innervation). Damage to one or more of these spinal cord segments or to motor nerve roots arising from these segments results in paralysis of the muscles concerned. c Psoas major is also a postural muscle that helps control deviation of trunk and is active during standing. d Four actions of sartorius (L. sartor, tailor) produce the once-common cross-legged sitting position used by tailors—hence the name. b

Lo we r Lim b

494

ANTERIOR AND MEDIAL COMPARTMENTS OF THIGH

Muscle attachments: Pectineus

Adductor brevis

Gracilis

Adductor longus

Adductor magnus

Obturator externus

Common iliac artery Internal iliac artery

Ischiopubic ramus

External iliac artery

Pubis

Obturator artery

Pectineus

Ischial tuberosity

Femoral artery (cut)

Profunda femoris artery (cut)

Attachment to pectineal line

Profunda femoris artery

Adductor brevis

Adductor longus

Attachments to linea aspera (on posterior aspect)

Adductor magnus

Femoral artery Perforating branches

Gracilis

Femoral artery

Medial supracondylar line

Adductor hiatus

Adductor tubercle

A

6.23

B

Anterior Views

C

D

ATTACHMENTS OF MUSCLES OF MEDIAL ASPECT OF THIGH

A. Overview of attachm ents. B. Pectineus, ad ductor longus, and gracilis. C. Adductor brevis. D. Adductor m agnus.

TABLE 6.6

MUSCLES OF MEDIAL THIGH

Muscle

Proxima l Atta chment

Dista l Atta chment a

Innerva tion b

Ma in Actions

Pectineus

Superior pubic ramus

Pectineal line of femur, just inferior to lesser trochanter

Femoral nerve (L2 and L3) may receive a branch from obturator nerve

Adducts and exes hip joint; assists with medial rotation of hip joint

Adductor longus

Body of pubis inferior to pubic crest

Middle third of linea aspera of femur

Obturator nerve, (L2, L3 , and L4)

Adducts hip joint

Adductor brevis

Body of pubis and inferior pubic ramus

Pectineal line and proximal part of linea aspera of femur

Obturator nerve (L2, L3 , and L4)

Adducts hip joint and, to some extent, exes it

Adductor magnus

Inferior pubic ramus, ramus of ischium (adductor part), and ischial tuberosity

Gluteal tuberosity, linea aspera, medial supracondylar line (adductor part), and adductor tubercle of femur (hamstring part)

Adductor part: obturator nerve (L2, L3 , and L4 ) Hamstring part: tibial part of sciatic nerve (L4 )

Adducts hip joint; its adductor part also exes hip joint, and its hamstring part extends it

Gracilis

Body of pubis and inferior pubic ramus

Superior part of medial surface of tibia

Obturator nerve (L2 and L3)

Adducts hip joint, exes knee joint, and helps rotate it medially

Obturator externus

Margins of obturator foramen and obturator membrane

Trochanteric fossa of femur

Obturator nerve (L3 and L4 )

Laterally rotates hip joint; steadies head of femur in acetabulum

Collectively, the rst ve muscles listed are the adductors of the thigh, but their actions are more complex (e.g., they act as exors of the hip joint during exion of the knee joint and are active during walking). a See Figure 6.22 for muscle attachments. b See Table 6.1 for explanation of segmental innervation. Numbers indicate spinal cord segmental innervation of nerves (e.g., L2, L3, and L4 indicate that the obturator nerve supplying adductor longus is derived from lumbar segments of the spinal cord; boldface type [L3 ] indicates main segmental innervation). Damage to one or more of these spinal cord segments or to motor nerve roots arising from these segments results in paralysis of the muscles concerned.

ANTERIOR AND MEDIAL COMPARTMENTS OF THIGH

External iliac artery and vein

Lo we r Lim b

495

Sacrum

Psoas

Piriformis Sacrospinous ligament Coccygeus

Obturator internus

Gracilis Internal pudendal artery Semitendinosus Gluteus maximus Sartorius

Adductor longus

Adductor magnus

Semitendinosus Rectus femoris Gracilis Semimembranosus

B. Anterior View

Pes anserinus

Sartorius

Vastus medialis

Semitendinosus

Forming pes anserinus: Gastrocnemius, medial head (cut)

Gracilis Semitendinosus

3 tendons merging to form pes anserinus

Sartorius

Soleus

A. Medial View

MUSCLES OF MEDIAL ASPECT OF THIGH A. Dissection. B. Muscular trip od . The sartorius, g racilis, and sem itend inosus m uscles form an inverted trip od arising from three d ifferent com p onents of th e hip b one. These m uscles course within three d ifferent com p artm ents, p erform three d ifferent functions, and are innervated b y three d ifferent nerves yet share a com m on d istal attachm ent. C. Distal attachm ent of sartorius, g racilis, and sem itend inosus m uscles. All three tend ons

C. Medial View

6.24 b ecom e th in and ap oneurotic and are collectively referred to as the p es anserinus. The gracilis is a relatively weak m em ber of the adductor group and hence can be rem oved without noticeable loss of its actions on the leg. Surgeons often t ran sp lan t t h e g racilis, or p art of it, with its nerve and blood vessels to replace a dam aged m uscle, in the hand, for exam ple.

496

Lo we r Lim b

ANTERIOR AND MEDIAL COMPARTMENTS OF THIGH

Anterior superior iliac spine Internal oblique

Iliacus Iliohypogastric nerve Nerve Femoral Artery Vein

Ilio-inguinal nerve Medial circumflex femoral artery

Ascending branch of lateral circumflex femoral artery

Pectineus Adductor longus

Sartorius

Branches of obturator nerve Adductor brevis

Rectus femoris

Profunda femoris artery Adductor brevis Descending branch of lateral circumflex femoral artery Adductor longus

Vastus lateralis

Nerve to vastus medialis Saphenous nerve

Vastus intermedius

Femoral artery Adductor magnus Rectus femoris

Gracilis

Sartorius

Vastus medialis

Nerve Vein Artery

Saphenous

Great saphenous vein

Anteromedial View

6.25

ANTEROMEDIAL ASPECT OF THIGH

• The lim b is rotated laterally. • The fem oral nerve breaks up into m ultiple nerves on entering the thigh. • The fem oral artery lies between two m otor territories: that of the obturator nerve, which is m edial, and that of the fem oral nerve, which is lateral.

• The nerve to the vastus m edialis m uscle and the saphenous nerve accom p any the fem oral artery into the adductor canal. • The profunda fem oris artery (deep artery of thigh) is the largest branch of the fem oral artery and the chief artery to the thigh.

LATERAL THIGH

Lo we r Lim b

497

Gluteal fascia (covering gluteus medius) (1)

1 8

Tensor fasciae latae (8)

2 Gluteus maximus (2)

Rectus femoris

Iliotibial tract

Vastus lateralis (7)

7

Long head

Biceps femoris (3)

Short head 3

6 Iliotibial tract (6)

Gastrocnemius (lateral head) (4)

4

A. Lateral View

9

Patellar ligament (5)

5

LATERAL ASPECT OF THIGH A. Surface Surface anatom an at o m y. y.Num Num bers bersrefer refertotostructures structures labeled (B). B. Disse in ( B)c-. t io Dissection B. n sh o w in gshowing t h e ilio the t ib ial iliotibial t ract ,tract, a t h icke a thickening n in g o f tof h ethe fascia faslat a, cia lata, w hwhich ich seserves rve s as as aa ttendon e n d o n for fo rthe t h egluteus g lut e us m axim m axim us and us

B. Lateral View

Head of fibula (9)

6.26 tensor an d t efasciae n so r fasciae latae. The latiliotibial ae . The tract iliotibial attaches tract to attaches the anterolateral to the anterolateral (Gerdy) tubercle (Gerdy) oftubercle the lateral of condyle the lateral of condyle the tibia.of the tibia.

Lo we r Lim b

498

BONES AND MUSCLE ATTACHMENTS OF THIGH

Key for B

Iliac crest

Proximal muscular attachment

Iliac fossa

Tuberculum of iliac crest

Distal muscular attachment

Anterior superior iliac spine

Iliopubic eminence Superior ramus of pubis

Ligamentous attachment

Pubic tubercle Pubic symphysis

Anterior inferior iliac spine Rim of acetabulum

Pubic crest Pecten pubis

Head of femur Greater trochanter

Body of pubis

Intertrochanteric line Lesser trochanter

Inferior ramus of pubis

Ramus of ischium

Obturator foramen

Iliacus

Sartorius Pectineus Adductor longus Gracilis

Rectus femoris

Ischial tuberosity

Ischiopubic ramus

Gluteus minimus Vastus lateralis Iliopsoas Vastus medialis

Femur

Obturator externus

Adductor brevis Adductor magnus

Vastus intermedius

Patella

Adductor tubercle Medial epicondyle

Lateral epicondyle Lateral femoral condyle

Medial femoral condyle

Apex of head Head Neck

Articularis genu

Medial and lateral tibial condyles Anterolateral (Gerdy) tubercle

Adductor magnus

Tuberosity

A. Anterior View

Fibula

Tibia

Iliotibial tract Biceps femoris

B. Anterior View

6.27

BONES OF THE THIGH AND PROXIMAL LEG

A. Bony features. B. Muscle attachm ent sites.

Patellar ligament

Lo we r Lim b

BONES AND MUSCLE ATTACHMENTS OF THIGH

Key for D

Iliac crest Posterior gluteal line

Proximal muscular attachment

Anterior gluteal line

Ilium

499

Distal muscular attachment Ligamentous attachment

Tuberculum (tubercle) of iliac crest

Posterior superior iliac spine Posterior inferior iliac spine Greater sciatic notch Ischial spine

Inferior gluteal line Neck of femur

Ischium

Gluteus medius Gluteus maximus

Gluteus minimus

Greater trochanter

Lesser sciatic notch

Iliotibial tract Tensor fasciae latae

Intertrochanteric crest

Ischial tuberosity

Sartorius Rectus femoris

Lesser trochanter Gluteal tuberosity

Pectineal line Spiral line

Gluteus medius Quadratus femoris

Gemelli Biceps femoris, long head Semitendinosus Adductor magnus

Linea aspera

Vastus lateralis Gluteus maximus Adductor magnus

Semimembranosus Iliopsoas

Femur

Pectineus

Adductor longus

Medial supracondylar line Adductor tubercle

Vastus intermedius

Lateral supracondylar line Popliteal surface

Vastus lateralis

Intercondylar fossa Lateral femoral condyle

Medial femoral condyle

Adductor brevis

Biceps femoris, short head Vastus medialis

Lateral tibial condyle

Medial tibial condyle

Apex of head Head of fibula Neck

Soleal line

Tibia

C. Posterior View

Adductor magnus Gastrocnemius, medial head

Plantaris Gastrocnemius, lateral head

Fibula Semimembranosus Popliteus Soleus

D. Posterior View

BONES OF THE THIGH AND PROXIMAL LEG (continued ) C. Bony features. D. Muscle attachm ent sites.

6.27

Lo we r Lim b

500

GLUTEAL REGION AND POSTERIOR COMPARTMENT OF THIGH

7

Gluteus medius (7)

6

Gluteus maximus (6)

Iliotibial tract (5) Sciatic nerve

Adductor magnus

Semitendinosus

4

Long head of biceps femoris

Semimembranosus (1)

1 5

Short head of biceps femoris

Common fibular (peroneal) nerve Gracilis

Tibial nerve

Biceps femoris (4) Tibial nerve

2

Plantaris

3

Common fibular nerve Gastrocnemius medial head (2)

A. Posterior View

6.28

Gastrocnemius lateral head (3)

B. Posterior View

MUSCLES OF THE GLUTEAL REGION AND POSTERIOR THIGH I

A. Surface anatom y. Num bers refer to structures labeled in ( B) . B. Sup er cial dissection. Muscles of gluteal region and p osterior thigh (ham string m uscles consist of sem im em branosus, sem itendinosus, and biceps fem oris).

Ham st rin g st rain s (pulled and/ or torn ham strings) are com m on in running, jum ping, and quick-start sports. The m uscular exertion required to excel in these sports m ay tear part of the proxim al attachm ents of the ham strings from the ischial tuberosity.

GLUTEAL REGION AND POSTERIOR COMPARTMENT OF THIGH

Lo we r Lim b

501

Gluteus medius Piriformis

Gluteus minimus

Superior gemellus

Piriformis

Obturator internus

Tensor fasciae latae

Superior gemellus

Inferior gemellus

Gluteus medius (cut)

Obturator internus Inferior gemellus Ischial tuberosity (location of ischial bursa)

Quadratus femoris

Quadratus femoris

Hamstring muscles (cut) Adductor magnus Greater trochanter (location of trochanteric bursa)

Sciatic nerve

Gluteus maximus

Adductor part Adductor magnus

Gluteus maximus Iliotibial tract

Hamstring part

Iliotibial tract Popliteal vein

Semitendinosus

Biceps femoris, short head

Popliteal artery

H

a

m

s

t

r

i

ngs

Biceps femoris

Vastus medialis Semimembranosus

Bellies of gastrocnemius (cut)

Adductor tubercle Semimembranosus

Oblique popliteal ligament

Biceps femoris long head (cut)

Plantaris

Plantaris Popliteus

Oblique popliteal ligament

Popliteus

Soleus Gastrocnemius, medial head

Soleus Gastrocnemius, lateral head

C. Posterior View

D. Posterior View

MUSCLES OF THE GLUTEAL REGION AND POSTERIOR THIGH (continued ) II AND III C. Muscles of gluteal region and posterior thigh with gluteus m axim us re ected. D. Adductor m agnus m uscle. The adductor m agnus has two parts: one belongs to the adductor group, innervated by the obturator nerve and the other to the ham string group, innervated by the tibial portion of the sciatic nerve. The trochanteric bursa separates the superior bers of the gluteus m axim us from the g reater trochanter of the fem ur, and the ischial bursa

6.28

separates the inferior part of the gluteus m axim us from the ischial tuberosity. Diffuse deep pain in the lateral thigh region (e.g., during stair climbing) may be caused by trochanteric bursitis. It is characterized by point tenderness over the greater trochanter, with pain radiating along the iliotibial tract. Ischial bursitis results from excessive friction between the ischial bursae and ischial tuberosities (e.g., as from cycling).

Lo we r Lim b

502

GLUTEAL REGION AND POSTERIOR COMPARTMENT OF THIGH

Gluteus maximus Gluteus medius

Tensor fasciae latae

Tensor fasciae latae

Sciatic nerve

Gluteus maximus (Max)

Gluteus minimus (Min) Gluteus medius

Gluteus maximus (cut and reflected)

Outline of sacrotuberous ligament

Quadratus femoris Gemelli

Piriformis (P) Gluteus medius (Med)

Quadratus femoris

Gluteal tuberosity

Gluteus maximus

Gluteal tuberosity

Iliotibial tract

A. Posterior View

Obturator internus and gemelli

Piriformis

C. Posterior View Anterior gluteal line

Tensor fasciae latae Max

Posterior gluteal line

Med P

Gluteus minimus

6.29

P Axis (center) of greater trochanter

Iliotibial tract

B. Anterior View

Min

D. Posterior View

E

Lateral Views

F

MUSCLES OF GLUTEAL REGION

A. and B. Attachments. C. Relationship of gluteal muscles. D. Gluteus maximus and tensor fasciae latae. E. Gluteus medius. F. Gluteus minimus.

TABLE 6.7

a

MUSCLES OF GLUTEAL REGION

Muscle

Proxima l Atta chment a (Red)

Dista l Atta chment a (Blue)

Innerva tion b

Ma in Actions

Gluteus maximus

Ilium posterior to posterior gluteal line, dorsal surface of sacrum and coccyx, sacrotuberous ligament

Iliotibial tract that inserts into lateral condyle of tibia; lower, deep bers to gluteal tuberosity

Inferior gluteal nerve (L5, S1 , S2 )

Extends hip joint and assists in lateral rotation; steadies thigh and assists in raising trunk from exed position

Gluteus medius

External surface of ilium between anterior and posterior gluteal lines; gluteal fascia

Lateral surface of greater trochanter of femur

Gluteus minimus

External surface of ilium between anterior and inferior gluteal lines

Tensor fasciae latae (TFL)

Anterior superior iliac spine and iliac crest

Anterior surface of greater trochanSuperior gluteal nerve ter of femur (L5 , S1) Iliotibial tract that attaches to lateral condyle (Gerdy tubercle) of tibia

Piriformis

Anterior surface of sacrum and sacrotuberous ligament

Superior border of greater trochan- Anterior rami of S1 ter of femur and S2

Obturator internus

Pelvic surface of obturator membrane and surrounding bones

Superior gemellus

Ischial spine

Inferior gemellus

Ischial tuberosity

Quadratus femoris

Lateral border of ischial tuberosity

Medial surface (trochanteric fossa) of greater trochanter of femur by common tendons

Nerve to obturator internus (L5, S1)

Quadrate tubercle on intertrochan- Nerve to quadratus teric crest of femur femoris (L5, S1)

Abducts and medially rotates hip joint c; keeps pelvis level when opposite leg is off ground and advances pelvis during swing phase of gait; TFL also contributes to stability of extended knee

Laterally rotate extended hip joint and abduct exed hip joint; steady femoral head in acetabulum

Laterally rotates hip joint,d steadies femoral head in acetabulum

See Figure 6.22 for muscle attachments. Numbers indicate spinal cord segmental innervation of nerves (e.g., L5, S1, and S2 indicate that the inferior gluteal nerve supplying gluteus maximus is derived from three segments of the spinal cord; boldface type [S1 , S2 ] indicates main segmental innervation). Damage to one or more of these spinal cord segments or to motor nerve roots arising from these segments results in paralysis of the muscles concerned. c Gluteus medius and minimus: anterior bers medially rotate hip joint and posterior bers laterally rotate hip joint. d There are six lateral rotators of the hip joint: piriformis, obturator internus, gemelli (superior and inferior), quadratus fem oris, and obturator externus. These muscles also stabilize the hip joint. b

GLUTEAL REGION AND POSTERIOR COMPARTMENT OF THIGH

Lo we r Lim b

503

Ischial tuberosity Cut tendon of semitendinosus

Biceps femoris long head Semitendinosus

Gluteal tuberosity of femur

Adductor magnus Vastus lateralis Gracilis

Semimembranosus

Biceps femoris: Short head

Biceps femoris* Semitendinosus* Semimembranosus*

Biceps femoris short head

Reflected attachment of semimembranosus forming oblique popliteal ligament

Sartorius Attachment of semimembranous to medial condyle of tibia

Semimembranosus Biceps femoris

Long head*

Attachment of biceps femoris to head of fibula

Cut tendon of semitendinosus

Biceps femoris

Investing fascia of popliteus

Semitendinosus *Hamstring muscles

A

Anterior View

B

C

D

Posterior Views

6.30

MUSCLES OF POSTERIOR THIGH A. Attachm ents. B. Super cial layer. C. Interm ediate layer. D. Deep layer.

TABLE 6.8 Musclea

MUSCLES OF POSTERIOR THIGH ( HAMSTRING) Proxima l Atta chment a (Red)

Semitendinosus

a b

Dista l Atta chment a (Blue)

Innerva tion b

Ma in Actions

Tibial division of sciatic nerve (L5, S1, and S2)

Extend hip joint; ex knee joint and rotate it medially; when hip and knee joints are exed, can extend trunk

Medial surface of superior part of tibia

Semimembranosus

Ischial tuberosity

Biceps femoris

Long head: ischial tuberosity Short head: linea aspera and lateral Lateral side of head of bula; tendon is split at supracondylar line of femur this site by bular collateral ligament of knee

See Figure 6.22 for muscle attachments. See Table 6.1 for explanation of segmental innervation.

Posterior part of medial condyle of tibia; re ected attachment forms oblique popliteal ligament to lateral femoral condyle

Long head: tibial division of sciatic nerve (L5, S1, and S2) Short head: common bular (peroneal) division of sciatic nerve (L5, S1, and S2)

Flexes knee joint and rotates it laterally; extends hip joint (e.g., when initiating a walking gait)

504

Lo we r Lim b

GLUTEAL REGION AND POSTERIOR COMPARTMENT OF THIGH

Superior gluteal artery Gluteus maximus

Piriformis Inferior gluteal artery and nerve Internal pudendal artery Pudendal nerve Nerve to obturator internus Sacrotuberous ligament

Gluteus medius Superior gemellus Obturator internus Inferior gemellus Branch of medial circumflex femoral artery Trochanteric bursa Quadratus femoris

Posterior cutaneous nerve of thigh

Gluteofemoral bursa Sciatic nerve

Branch of medial circumflex femoral artery

Adductor magnus

Biceps femoris, long head 1st perforating artery S