Kadasne's Textbook of Anatomy (Clinically Oriented Upper and Lower Extremities) [1, 1ed.] 8184484550, 9788184484557

Table of contents :
Prelims
Chapter-01_Synopsis on Osteology of Thorax, Abdomen and Pelvis
Chapter-02_Pelvis
Chapter-03_Thorax
Chapter-04_Pleura
Chapter-05_Lungs
Chapter-06_Trachea
Chapter-07_Pericardium
Chapter-08_Heart
Chapter-09_Thoracic Aorta
Chapter-10_Oesophagus
Chapter-11_Thoracic Duct and Veins in the Thorax
Chapter-12_Thymus
Chapter-13_Sympathetic Chain
Chapter-14_Intervertebral Joints
Chapter-15_The Perineum
Chapter-16_Anal Triangle
Chapter-17_Ischio-Rectal Fossa
Chapter-18_Anal Canal
Chapter-19_Urogenital Triangle
Chapter-20_Deep Perineal Pouch
Chapter-21_Penis
Chapter-22_Female Perineum
Chapter-23_Abdomen
Chapter-24_Muscles of the Anterior Abdominal Wall
Chapter-25_Hernia
Chapter-26_Spermatic Cord
Chapter-27_Testis
Chapter-28_Epididymis
Chapter-29_Abdominal Cavity and Peritoneum
Chapter-30_Spleen
Chapter-31_Liver
Chapter-32_Gallbladder
Chapter-33_Duodenum
Chapter-34_Pancreas
Chapter-35_Portal Vein
Chapter-36_Posterior Abdominal Wall
Chapter-37_Kidneys and Suprarenal Glands
Chapter-38_Suprarenal Glands
Chapter-39_Ureter
Chapter-40_Small Intestine
Chapter-41_Abdominal Aorta
Chapter-42_Inferior Vena Cava
Chapter-43_Lumbar Plexus
Chapter-44_Coeliac Ganglion
Chapter-45_Diaphragm
Chapter-46_Pelvis
Chapter-47_Anal Canal
Chapter-48_Urinary Bladder
Chapter-49_Prostate
Chapter-50_Vas Deferens
Chapter-51_Seminal Vesicles
Chapter-52_Female Genital Organs
Chapter-53_Vagina
Chapter-54_Uterine Tubes
Chapter-55_Ovary
Chapter-56_Urethra
Chapter-57_Internal Iliac Artery
Chapter-58_Internal Iliac Vein
Chapter-59_Sacral Plexus
Chapter-60_Joints of the Pelvis
Chapter-61_Muscles of the Back
Chapter-62_Lumbar Fascia
Chapter-63_Surface Marking of Important Structures
Chapter-64_Clinical Pictures
Index

Citation preview

Kadasne’s Textbook of

ANATOMY (Clinically Oriented)

Kadasne’s Textbook of

ANATOMY (Clinically Oriented) Volume 2: Thorax, Abdomen and Pelvis DK Kadasne MS FRCS FICS

Emeritus Professor Department of Anatomy Pandit Jawaharlal Nehru Medical College DMIMS (a Deemed University) Sawangi, Wardha Maharashtra, India

®

JAYPEE BROTHERS MEDICAL PUBLISHERS (P) LTD New Delhi • Ahmedabad • Bengaluru • Chennai • Hyderabad • Kochi • Kolkata • Lucknow • Mumbai • Nagpur

Published by Jitendar P Vij Jaypee Brothers Medical Publishers (P) Ltd Corporate Office 4838/24 Ansari Road, Daryaganj, New Delhi - 110002, India, +91-11-43574357 (30 lines) Registered Office B-3 EMCA House, 23/23B Ansari Road, Daryaganj, New Delhi 110 002, India Phones: +91-11-23272143, +91-11-23272703, +91-11-23282021, +91-11-23245672, Rel: +91-11-32558559 Fax: +91-11-23276490, +91-11-23245683 e-mail: [email protected], Website: www.jaypeebrothers.com Branches  2/B, Akruti Society, Jodhpur Gam Road Satellite Ahmedabad 380 015 Phones: +91-79-26926233, Rel: +91-79-32988717 Fax: +91-79-26927094, e-mail: [email protected]  202 Batavia Chambers, 8 Kumara Krupa Road, Kumara Park East Bengaluru 560 001 Phones: +91-80-22285971, +91-80-22382956, +91-80-22372664 Rel: +91-80-32714073, Fax: +91-80-22281761, e-mail: [email protected]  282 IIIrd Floor, Khaleel Shirazi Estate, Fountain Plaza, Pantheon Road Chennai 600 008 Phones: +91-44-28193265, +91-44-28194897, Rel: +91-44-32972089 Fax: +91-44-28193231, e-mail: [email protected]  4-2-1067/1-3, 1st Floor, Balaji Building, Ramkote Cross Road Hyderabad 500 095 Phones: +91-40-66610020, +91-40-24758498, Rel:+91-40-32940929 Fax:+91-40-24758499, e-mail: [email protected]  No. 41/3098, B & B1, Kuruvi Building, St. Vincent Road Kochi 682 018, Kerala Phones: +91-484-4036109, +91-484-2395739, +91-484-2395740 e-mail: [email protected]  1-A Indian Mirror Street, Wellington Square Kolkata 700 013 Phones: +91-33-22651926, +91-33-22276404, +91-33-22276415 Rel: +91-33-32901926, Fax: +91-33-22656075, e-mail: [email protected]  Lekhraj Market III, B-2, Sector-4, Faizabad Road, Indira Nagar Lucknow 226 016 Phones: +91-522-3040553, +91-522-3040554 e-mail: [email protected]  106 Amit Industrial Estate, 61 Dr SS Rao Road, Near MGM Hospital, Parel Mumbai 400012 Phones: +91-22-24124863, +91-22-24104532, Rel: +91-22-32926896 Fax: +91-22-24160828, e-mail: [email protected]  “KAMALPUSHPA” 38, Reshimbag, Opp. Mohota Science College, Umred Road Nagpur 440 009 (MS) Phone: Rel: +91-712-3245220, Fax: +91-712-2704275, e-mail: [email protected] USA Office 1745, Pheasant Run Drive, Maryland Heights (Missouri), MO 63043, USA, Ph: 001-636-6279734 e-mail: [email protected], [email protected] Kadasne’s Textbook of Anatomy (Clinically Oriented) (Volume 2) © 2009, Jaypee Brothers Medical Publishers All rights reserved. No part of this publication should be reproduced, stored in a retrieval system, or transmitted in any form or by any means: electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the author and the publisher. This book has been published in good faith that the material provided by author is original. Every effort is made to ensure accuracy of material, but the publisher, printer and author will not be held responsible for any inadvertent error(s). In case of any dispute, all legal matters to be settled under Delhi jurisdiction only. First Edition: 2009 ISBN 978-81-8448-456-4 Typeset at JPBMP typesetting unit Printed at Rajkamal Press

Dedicated to the Sacred Memory of My Late Beloved Parents

FOREWORD Peeping into memory lanes of the yester years, it vividly comes into my focused attention of the Herculean difficulties which I had to face as an ordinary student of first MBBS in the early 70's, while groping into the annals of Anatomy as a subject. It appeared to be "tough, baffling and difficult to grasp", and much more, difficult to 'retain' for the purposes of 'recall'. Frankly speaking, it was genuinely a dreadful proposition till we were told by our seniors to just fall back to the notes titled' Approach to Anatomy' penned by none else than respected Dr DK Kadasane Sir. It realistically had an astonishing effect to the extent that what was 'dreadful; till the previous day became understandingly lovable subsequent thereto. It was some sort of realistic magic which till date does not go out of the memory. I therefore feel greatly privileged to be writing this foreword for the present book, which is a genuine manifestation of unparalleled creativity brought out by respected Dr DK Kadasane Sir in his lucid and free flowing style. The contents, description, syntaxing and diagrammatic depiction, all taken together make it look as if it is "Anatomy made easiest" for one and all. Indeed, it is a great venture which is nothing but a depiction of the commitment that Dr DK Kadasane Sir has harboured deep in his heart and mind for the subject of anatomy all his life and has never fallen short when he started writting the book which would cater to the cause of the learners as well as teachers in a meaningful way. No amount of praise showered on him would be sufficient to commensurate with his single minded devotion to the teaching and learning of the subject of anatomy and facilitating it in a way which would really be memorable on all counts. I have every reason to believe that this book entitled Kadasne's Textbook of Anatomy (Clinically Oriented) would not only be handy, useful, purposive and relevant to the requirements of students and teachers of anatomy but would also be of significant consequence to the teachers of surgery and its allied specialities. The unique feature of applied aspects in this book is due to the fact that Dr Kadasne is a qualified Anatomist as well as Surgeon of cognition and repute. I take the privilege of saluting the 'unending zeal and unfathomable commitment of 'teacher of teachers' respected Dr DK Kadasane Sir, inspite of being aware of the fact that any expression howsoever, genuine and bonafide it be, would not be able to match his creative prowess.

Vedprakash Mishra Chairman Post Graduate Medical Education Committee, Medical Council of India, New Delhi

PREFACE I had the pleasure of teaching Anatomy at the Government Medical College, Nagpur and Surgery at the Indira Gandhi Medical College, Nagpur. I am convinced that surgery brings meaning to anatomy. Surgery is an applied anatomy in the true sense. Anatomy was written and taught by surgeons and physicians in the golden era of rise of medicine. Anatomy was brought to a respectable stage by great surgeons and physicians. It happened in the days when touching of dead and the blood was considered a sin. The call was given to all the anatomists over the world by a famed and the pioneer surgeon as “Anatomist should come out of the dead house and prove their worth in other clinical sciences. In case of the members of clinical sciences prevent them, the loss is theirs—the loss of humanity”. Every structure in the body has the hidden surgical and clinical thrill of practical importance. It is only on the foundation of anatomy the clinical sciences progressed to the stage of organ transplant. Emergence of the non-invasive techniques of investigation have acted as a boon for anatomy in its further research and clinical application. Keeping in view the thoughts expressed, I ventured to write a book to create interest and enthusiasm amongst the students while learning anatomy. No book is complete and no book can be comprehensive. DK Kadasne

ACKNOWLEDGEMENTS My acknowledgements are due to my revered teachers, i.e. Dr NS Sahastrabuddhe, Dr Gopal Rao, Dr SL Robert, Dr PC Bansal and Dr PN Dubey for their support and guidance. Mr Datta Meghe, MP and the Chancellor of the DMIMS gave me an opportunity to enter into the academic field of teaching anatomy in addition to my surgical practice. This is the major factor which inspired me to write a book of this type. Mr Sagar Meghe, MLA played a pivotal role in keeping me engaged in the teaching of anatomy. Dr Dilip Gode, presently the Professor of Surgery in Pandit Jawaharlal Nehru Medical College, Sawangi, Wardha has always acted as my well wisher and supporter, whom I can never forget. I am indebted to Dr Joharapurkar, Director, Datta Meghe Institute, Department of Post Graduate Research and Medical Education and the member of the Management Council for encouragement and support. My thanks are due to Dr Patel, the Dean of the Pandit Jawaharlal Nehru Medical College, Sawangi for appreciation. Dr Mrs Fulzele, Professor and Head of the Department of Anatomy of the Pandit Jawaharlal Nehru Medical College, Sawangi deserves my grateful thanks for discussions during the preparation of the book. Dr Mrs Rawalani deserves thanks for showing interest in my undertaking. I could not have presented the book in the present form without the generous donation of the clinical material provide by my friends who are renowned experts in their respective fields. Dr Shirish Dhande, a renowned radiologist of the city made the X-rays and the MRI available. It is my honour that Dr Vedprakash Mishra, Vice-Chancellor of the DMIMS University, Sawangi, Wardha, and the Chairman of Post Graduate Medical Education Committee, Medical Council of India, New Delhi, a doyen in the science of physiology agreed to write a foreword for this book. Dr GM Taori, the Director of CIMS, Bajaj Nagar, Nagpur whole heartedly co-operated with me in obtaining the consent of the management committee of the institution for permission of using the beautiful cerebral angiogram. The skill and the knowledge of Dr Kothekar, who is the master in his own field need not be highlighted any more. Dr Prakash Heda of Nairobi, a student and my friend has supported me constantly whether he lived in India or abroad. I thank him sincerely. My thanks also go to Dr Neeta Kulkarni, Professor and Head of the Department of Anatomy, Dr SMCSI Medical College, Karakonam, Trivendrum who always enquired about the progress of the book. I also thank to Dr Sushma Deshmukh, Dr Ravi Deshmukh, Dr Tule, the pediatric surgeon, and Dr Mukewar, the Director of Gastrointestinal Institute of Central India. Dr SD Suryawanshi Professor and Head of the Department of Medicine, Indira Gandhi Medical College, Nagpur, acted as my constant critic during the preparation of this book. I thank him profusely. I have all the appreciation for the work done by Manoj Dharmadhikari for computerised typing of the manuscript. Mr Avinash Kokate did an excellent work in drawing the diagrams artistically with colour. I cannot forget both of them for their devotion and punctuality. I shall be failing to furnish my duty if I do not express my gratitude to Dr Kishore Taori, the dynamic professor of radiology of the Government Medical College, Nagpur for providing me the necessary material for the production of this book. My better half, Mrs Arati Kadasne, took pains to go through the manuscript and helped me untiringly till the completion of the book. Dr Shivraj Mulik, ophthalmic surgeon provided actual photographs of fundoscopic examination showing retinal vessels. Dr BJ Chikodi, Ex-civil Surgeon and Dr JS Mulik, ophthalmic surgeon encouraged me in the production of this book. I express my gratitude to them.

XII Kadasne’s Textbook of Anatomy (Clinically Oriented) My thanks also go to Dr Dasgupta, Dean, Lata Mangeshkar Medical Hospital, who provided the clinical photographs for publication of my book and Dr Kothe, the plastic surgeon who provided beautiful clinical photographs of cleft lip and palate. My thanks are due to Dr Padole, surgeon and Dr Neral and Dr Jape, radiologists for their encouraging comments and helping hands. Dr Mrs Pushpa Jagtap, Ex-Dean of Indira Gandhi Medical College, Nagpur and her two brilliant sons, namely Dr Prashant, cardiovascular surgeon of Wockhardt Hospital, Nagpur and Dr Jitendra Jagtap, renowned orthopedic surgeon have extended their supports whole heartedly, I cannot forget them. Dr Mangrulkar took pains to provide necessary photographs for their reproduction, I am also grateful to him. Dr KN Ingle, Professor of Pandit Jawaharlal Nehru College, Sawangi, Wardha has always acted as my source of inspiration, so, I cannot forget him. I am under the heavy obligations of Hon’ble Datta Meghe, MP and the Chancellor of Datta Meghe Institute of Medical Sciences for the friendly approach, advice and appreciation, who allowed me to continue my academic association with the subject of anatomy by appointing me as Professor Emeritus of Anatomy in his prestigious institute. It is this institute which encouraged me to continue my academic activity. Although I was engaged in my surgical practice, the credit for production of this book goes to the DMIMS. I cannot forget the friendly and helpful approach of the Professor of surgery, Dr Vinay Shahapurkar, who also made available so many clinical photographs in the publication of this book. I am grateful to Shri Jitendar P Vij, CMD of M/s Jaypee Brothers Medical Publishers Pvt. Ltd. for publishing this book. I acknowledge the contribution of Mr Tarun Duneja, the Director (Publishing) of Jaypee Brothers and his team particularly Mr DC Gupta (Copyeditor), Ms Seema Dogra (Cover Designer) and Mr Sumit Kumar (Graphic Designer) who deserve my sincere thanks. I am extremely grateful to my beloved students who always appreciated and inspired me for teaching the subject. Last but not least, I am extremely grateful to Almighty who has allowed me to achieve my goal.

CONTENTS Synopsis on Osteology of Thorax, Abdomen and Pelvis ..................................................... 361 Pelvis ............................................................................................................................................ 373 Thorax .......................................................................................................................................... 379 Pleura ........................................................................................................................................... 399 Lungs ............................................................................................................................................ 406 Trachea ........................................................................................................................................ 413 Pericardium ................................................................................................................................ 426 Heart ............................................................................................................................................ 431 Thoracic Aorta ............................................................................................................................ 453 Oesophagus ................................................................................................................................ 466 Thoracic Duct and Veins in the Thorax ................................................................................. 477 Thymus ........................................................................................................................................ 486 Sympathetic Chain .................................................................................................................... 489 Intervertebral Joints ................................................................................................................... 491 The Perineum ............................................................................................................................. 494 Anal Triangle .............................................................................................................................. 495 Ischio-Rectal Fossa ..................................................................................................................... 496 Anal Canal ...................................................................................................................................500 Urogenital Triangle .................................................................................................................... 502 Deep Perineal Pouch ................................................................................................................. 508 Penis ............................................................................................................................................. 511 Female Perineum .......................................................................................................................519 Abdomen ..................................................................................................................................... 522 Muscles of the Anterior Abdominal Wall .............................................................................. 529 Hernia .......................................................................................................................................... 542 Spermatic Cord ........................................................................................................................... 550 Testis ............................................................................................................................................ 551 Epididymis .................................................................................................................................. 557 Abdominal Cavity and Peritoneum ........................................................................................ 558 Spleen .......................................................................................................................................... 569 Liver ............................................................................................................................................. 573 Gallbladder ................................................................................................................................. 582 Duodenum .................................................................................................................................. 587 Pancreas ...................................................................................................................................... 593 Portal Vein ...................................................................................................................................598 Posterior Abdominal Wall ........................................................................................................ 602 Kidneys and Suprarenal Glands ............................................................................................. 605

XIV Kadasne’s Textbook of Anatomy (Clinically Oriented) Suprarenal Glands .................................................................................................................... 612 Ureter ........................................................................................................................................... 615 Small Intestine ........................................................................................................................... 620 Abdominal Aorta .......................................................................................................................636 Inferior Vena Cava .................................................................................................................... 639 Lumbar Plexus .......................................................................................................................

643

Coeliac Ganglion ........................................................................................................................ 644 Diaphragm .................................................................................................................................. 645 Pelvis ............................................................................................................................................ 649 Anal Canal ...................................................................................................................................660 Urinary Bladder .......................................................................................................................... 666 Prostate ........................................................................................................................................673 Vas Deferens .............................................................................................................................. 677 Seminal Vesicles ........................................................................................................................ 679 Female Genital Organs ............................................................................................................. 680 Vagina .......................................................................................................................................... 689 Uterine Tubes ............................................................................................................................. 691 Ovary ............................................................................................................................................ 693 Urethra ......................................................................................................................................... 695 Internal Iliac Artery ................................................................................................................... 697 Internal Iliac Vein ...................................................................................................................... 702 Sacral Plexus ............................................................................................................................... 703 Joints of the Pelvis ...................................................................................................................... 705 Muscles of the Back ................................................................................................................... 707 Lumbar Fascia ............................................................................................................................708 Surface Marking of Important Structures .............................................................................. 709 Clinical Pictures .......................................................................................................................... 710 Multiple Choice Questions ............................................................................................................ 716 Index ............................................................................................................................................... i-v

Synopsis on Osteology of Thorax, Abdomen and Pelvis

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SYNOPSIS ON OSTEOLOGY OF THORAX, ABDOMEN AND PELVIS Before a student starts his study of abdomen, thorax, pelvis and the perineum, he should have a general idea of the bony foundation of these regions. Purpose of this small chapter is to make him or her familiar with the bones and their general arrangement in the human body, as seen in an anatomical position. Have a look at the fully articulated skeleton of the human body (Figure 1). Immediately below the skull you see cervical spine, below that, view of the thoracic portion of the vertebral column is hidden by a flat bone having three pieces. This bone is known as sternum. Sternum presents a quadrilateral upper piece known as manubrium. Immediately below the manubrium is the body of the sternum, made of four segments. This forms the middle piece. The lowest piece is small and presents as the triangular apex. This is known as the xiphoid process or the xiphisternum. Manubrium of the sternum presents the small concavity at its upper end. It is known as the supra-sternal notch. On either side of the suprasternal notch are the facets for clavicles. It forms the sternoclavicular joint. Clavicle runs horizontally and articulates with the acromion process of the scapula. The joint between lateral end of the clavicle and the acromion process of the scapula is known as acromio-clavicular joint. It is the clavicle which hides the first rib and protects, hence rarely fractured. This fact is important as one cannot palpate the first rib. The junction between the manubrium and body of sternum presents a ridge which can be palpated. This is known as sternal angle of Louis. Laterally the junctional zone between the manubrium and the body of the sternum presents articulation with the 2nd costal cartilage. Counting of the ribs is done from the second costal cartilage. Please note that the 7th rib articulates with the sternum at the junction of body and xiphoid process. The 8th, 9th and 10th ribs articulate with each other and do not go to sternum. 11th and 12th ribs present free anterior ends and are known as floating ribs. Due to the mobility they are rarely fractured. Ribs from 1 to 7 are attached to the sternum by costocartilages. In the post-mortem, thorax can be opened by cutting the costal cartilages. The 7th, 8th, 9th and the 10th ribs together presents an arched appearance. It is known as subcostal arch. Immediately below the xiphoid process is the 10th thoracic vertebra, which forms part of the vertebral column. Below it lie 11 and the 12th thoracic vertebrae. This is followed by five massive lumbar vertebrae. The size of the lumbar vertebrae increases from 1st to the 5th. Each lumbar vertebra presents a transverse process on either side, which is small except that of the 5th. Fifth lumbar vertebra lower down, joins the broad, triangular bone known as the sacrum. Its apex articulates with the coccyx below. The base of the sacrum has sacral promontory pointing anteriorly. The middle part of the base of the sacrum articulates with the body of the 5th lumbar vertebra. The parts

362

Kadasne’s Textbook of Anatomy (Clinically Oriented) on either side the lumbar articular area of the base is known as ala of the sacrum. Ala of the sacrum articulates with the hip bone to form sacroiliac joint. The hip bones articulate directly infront. The joint is the midline is known as the symphysis pubis. It is the secondary cartilaginous joint.

Figure 1 Showing part of articulated skeleton as seen from the front

First rib (Figure 2):

Superiorly hip bone presents the iliac crest, 5 cm behind the anterior superior iliac spine lies the iliac tubercle. The line from the iliac tubercles passes through the 5th lumbar vertebra, while the intercristal line between iliac crests passes through the 4th lumbar vertebra. Anterior end of iliac crest is known as the anterior superior iliac spine. Above the symphysis pubis, by the side of the midline there are horizontally placed crests. They are known as pubic crests. Pubic crest ends into the pubic tubercle laterally. It is the highest, strongest and is the most curved rib. It presents small rounded head having a single complete facet meant for body of 1st thoracic vertebra. As the rib is not twisted it presents superior and the inferior surfaces, lateral and the medial borders. Situated in the middle of the medial border is scalene tubercle. Scalene tubercle provides insertion to the scalenus anterior muscle, the key muscle of the neck. The groove for the subclavian vein is in front of the scalene tubercle, while the groove for the subclavian artery lies behind. Inner border of

Synopsis on Osteology of Thorax, Abdomen and Pelvis

363

the first rib gives attachment to the supra-pleural membrane. It is also known as Sibson’s fascia. First rib anteriorly articulates with the manubrium by means of a joint which is known as Synostosis (Synostosis means a joint which does not move.) The joints between the ends of the 2nd to 7th costal cartilages articulate with the sternum by means of synovial joints. As the first rib is raised or depressed the manubrium and the first ribs act together like a single unit. Figure 2 Showing superior surface of 1st rib with relations and attachments

Superior Surface of the First Rib:

Neck of the First rib (see Figure 8):

Aid to Memory:

Lateral border of the first rib gives origin to the part of the serratus anterior muscle. Behind the subclavian artery lies the lower trunk of the brachial plexus and the area behind gives insertion to the scalenus medius muscle. Anterior part of superior surface towards the costal end gives origin to the subclavius muscle and provides an attachment for the costo-clavicular ligament. Neck of the first rib lies between the head medially and the tubercle laterally. Anterior relation of the neck of the first rib. They are 1. Ventral ramus of the 1st intercostal nerve 2. Superior intercostal artery and 3. The sympathetic chain from lateral to medial side. Anterior relations of the neck of first rib can be remembered as “NAC” (instead of neck) from lateral to medial side N- Nerve, Artery C –chain sympathetic. Peculiarities of the first rib: 1. It is the highest, strongest and the most curved rib. 2. Presents superior and inferior surfaces, medial and the lateral borders unlike other ribs. 3. Has no sub-costal groove. 4. Forms an important part of the thoracic inlet. 5. Provides bed for the subclavian vein, subclavian artery and the lower trunk of the brachial plexus. 6. Plays an important in the thoracic outlet syndrome. Lower trunk of the brachial plexus and the subclavian artery are compressed between the first rib and the clavical causing neurovascular symptoms. These symptoms are severe in case of an additional rib i.e. cervical.

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Kadasne’s Textbook of Anatomy (Clinically Oriented)

Clinical:

Second Rib (see Figure 9):

Eleventh and Twelfth Ribs:

Typical Rib (Figure 3):

Although it is the strongest and well protected rib, fracture of the first rib occurs in severe degrees of the chest injuries causing damage to the great blood vessels of the neck and the upper limb. It is important to remember that 30% cases of fracture of first rib are likely to die. It has the larger curvature. Tubercle of 2nd rib has an articular and nonarticular parts. It presents small subcostal groove. It’s both ends touch the flat surface while posterior end of the typical rib rises up from table. The outer middle part of the second rib has a rough area which provides origin to the serratus anterior muscle. Second rib articulates with the sternum at the sternal angle of Louis at it’s costal end through the synovial joint. They are neck-less and tubercle-less. Eleventh rib has a shallow subcostal groove while the twelfth has none. Due to the absence of the tubercles on the 11th and the 12th ribs, the facets on the transverse processes of 11th and the 12th vertebrae are absent. The 12th spinal nerve is known as subcostal nerve. The 10th, 11th and the 12th ribs present small articular facets on their heads. The 10th rib differs from the 11th and the 12th in two respects i.e. it has a tubercle and the neck too. Each typical rib presents anterior, posterior ends and the body. Anterior end presents a shallow depression for costal cartilage. Body presents the rounded upper, the sharp lower borders and the subcostal groove. Subcostal groove is occupied by three structures from above downwards e.g. intercostal artery, vein and the intercostal nerve. Head has two articular facets separated by the crest. Please note that the lower facet is larger and it articulates with the numerically corresponding vertebra. Lower facet is logical, e.g. 8th rib’s lower facet articulates with 8th thoracic vertebra. Immediately beyond the head lies the neck laterally. At the end of the neck there is a tubercle having articular and non-articular areas. Articular part is again logical as it articulates with the transverse process of the numerically corresponding vertebra. Non-articular part gives attachment to the costo-transverse ligament.

Figure 3 Showing typical rib of right side

Cervical Rib:

It is an extra rib representing costal element of the 7th cervical vertebra arising from the anterior tubercle of the transverse process of the 7th cervical vertebra. It may actually join the first rib directly or indirectly through a fibrous band. It can compress the lower trunk of the brachial plexus leading to the pain, radiating along the medial side of forearm and may lead to wasting of the small muscles of hand. Compression of the subclavian artery can cause vascular symptoms in the upper limb.

Synopsis on Osteology of Thorax, Abdomen and Pelvis Sub-periosteal Rib Resection:

365

1. The segment of the rib is removed after incising the anterior and the posterior layers of the periosteum for better thoracic approach. 2. In sub-periosteal resection the rib generates from the remaining osteogenic part of the periosteum. 3. In coarctation of aorta the ribs present the notched appearance in the X-ray produced by the pressure of enlarged collaterals at their lower borders. 4. Fracture of the rib occurs at the angle due to compression force. First and second ribs being well protected by the clavicle are rarely fractured. Due to free mobility, the 11th and the 12th ribs escape fracture.

CLINICAL Compression Test: Typical Thoracic Vertebra (Figures 6 and 7):

First Thoracic Vertebra:

Antero-posterior compression of chest in supine position gives pain in case of the fracture of a rib at the site. Bilateral compression of the chest from either side gives pain at the fractured site. It can be identified due to the presence of articular facets on the body of the vertebra for the head of the rib. A typical thoracic vertebra presents a body, which is compressed from side to side and is heart shaped. At the sides it presents superior and inferior costal facets for heads of the ribs (Figures 6 and 7). Attached to the body, posteriorly is the vertebral arch. The circular opening within the ring is known as the vertebral foramen. It is meant for the spinal cord. Posteriorly in the middle of the vertebral arch is the spine which is directed backwards and downwards except that of the 1st and the 12th thoracic vertebrae which are horizontally placed. At the junction of the middle of the each half of the vertebral arch there is transverse process directed backwards and laterally. The part of the vertebral arch between the body and transverse process is known as pedicle and the part between spine and transverse process is known as the lamina. Situated at the junction of the transverse process and arch are the superior and inferior articular processes. Pedicles has a notch above and below. They are known as vertebral notches. Vertebral notch of the vertebra below and the vertebra above form the intervertebral foramen through which passes the spinal nerve. Please remember that the intervertebral foramen in thoracic region is directed laterally and can be seen in lateral X-ray of the thoracic spine. The intervertebral foramen in cervical region cannot be seen from lateral side as it is directed postero-laterally. Two vertebral bodies are connected by means of intervertebral disc. The joint formed is the secondary cartilaginous joint. The intervertebral disc has two parts, the central portion, which is like a tooth-paste, is known as nucleus pulposus and the peripheral portion as annulus fibrosus. When annulus fibrosus breaks, nucleus pulposus comes out normally in posterolateral direction. This is known as prolapse of the intervertebral disc (PID). First thoracic vertebra can be identified from the typical thoracic vertebra as it has a small body having a shape of a cervical vertebra. The posterolateral part of the body is raised like a cervical vertebra due to which the superior vertebral notch becomes prominent which is not seen in other thoracic vertebrae. The articular facet on the body meant for the head of

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Synopsis of Atypical Thoracic Vertebrae:

Clinical:

Typical Lumbar Vertebra:

Sternum (Figure 4):

the 1st rib is circular and complete. It has a long spine which runs horizontally. Out of the atypical thoracic vertebrae i.e. 1, 10, 11 and 12 have complete circular facets on the body. In the 9th thoracic vertebra the inferior costal facet is absent (Ninth has NO). The 11th and the 12th ribs are tubercleless and has no facets on the transverse processes, of the corresponding vertebrae. First thoracic vertebra has a complete circular facet on the body for the head of the first rib, facet for the tubercle of the first rib on the transverse process and the long horizontal spine. Twelfth thoracic vertebra has a complete facet on the body and no facet on the transverse process since the 12th rib does not have a tubercle. It has a long horizontal spine. As the articular surfaces of the articular processes of the thoracic vertebrae are vertical, the dislocation of the thoracic spine is always accompanied by a fracture. However in the cervical region, articular facets are sloping which results in dislocation without fracture. Vertebral venous plexus plays an important role in metastatic spread of cancer. Cancer of prostate spreads to vertebrae through vertebrae venous plexus. Veins of vertebrae venous plexus are devoid of valves during increased intra-abdominal pressure cancer cells travel to the spine (Reversal of blood flow). Vertebral venous plexus has mainly two components, inside the vertebral canal and outside inner and outer plexuses are further divided into anterior and the posterior. They are connected to intervertebral, intercostal and lumbar veins. Basi-vertebral vein drains into the anterior internal plexus from the posterior aspect of the body of vertebra. Intervertebral disc being avascular is entirely free from following: 1. Metastasis 2. Avascular necrosis 3. Pressure necrosis, e.g. in aneurysm of abdominal aorta bodies of the vertebrae are eroded and not the intervertebral discs. 4. Infection. In tuberculosis of spine body of the vertebra gets destroyed, compressed and collapsed, but the closely related disc escapes unhurt, maintaining the intervertebral space as normal. Its body is larger and kidney shaped and does not have facet on the body for the head of the rib as there are no ribs in the lumbar region. Vertebral foramen is triangular. Spinous process is quadrilateral and horizontally placed. Superior articular process is directed medially and backwards. Its posterior border is known as mamillary process. Transverse processes are thin and long with the exception of the 5th. At the posterior and inferior parts of the root of each transverse process there is small, rough accessory process. Fifth lumbar vertebra has following peculiarities: 1. Large body 2. Strong transverse processes as it approachs the base of sacrum having large alae. 3. Quadrilateral spine: Large transverse process helps in identifying the fifth lumbar vertebra from the others. Sternum forms the anterior wall of the thoracic cage. It has three pieces i.e. manubrium, body and the xiphoid process, which articulate to form a single bone.

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Figure 4 Showing sternum viewed anteriorly

Sternum has anterior and posterior surfaces. Manubrium presents the suprasternal notch above in the middle. It articulates laterally with the clavicles and the joint formed is known as the sternoclavicular joint. Manubrium articulates with the 1st costal cartilage through the joint which is synchondrosis (Does not move). Body of the sternum has four segments known as sternebrae. Junction of the manubrium and the body presents an angle anteriorly known as the sternal angle of Louis and is marked by the transverse ridge anteriorly which can be felt while counting of the ribs. The joint between the body and the manubrium is a symphysis. Xiphisternal joint cannot be called as symphysis as it obliterates in old age. Seventh costal cartilage is attached at the xiphisternal joint. The 3, 4, 5, 6 costal cartilages are attached to the body of the sternum through synovial joints. Attachment of the anterior surface of the sternum (Figure 4): i. Sternal head of sternomastoid arises from the anterior surface of the manubrium. ii. Sternocostal head of the pectoralis major muscle arises from the lateral half of the whole of the sternum and the corresponding costal cartilages. iii. Attached to the xiphisternum are the aponeuroses of internal and the transverse abdominis muscles. iv. Tip of the xiphoid process gives attachment to the linea alba. Posterior surface of sternum (Figure 5): 1. Sternohyoid and sternothyroid are attached to the back of the manubrium. Attachment of sternothyroid is below and that of the sternohyoid is above. Aid to Memory: Origin of the sternohyoid is high’ hyoid—high. 2. Sternocostalis muscle arises from lower two segments of the body of the sternum and the xiphoid process. 3. Xiphoid process provides origin to the fibres of the diaphragm.

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Figure 5 Sternum viewed from behind

Figure 6 Typical thoracic vertebra seen from above

Figure 7 Showing typical thoracic vertebra lateral view

Figure 8 Showing anterior relations of the neck of 1st rib (right) (NAC) from lateral to medial

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Figure 9 Showing 2nd rib (right side)

CLINICAL Sternal Puncture: Sternotomy: Myocardial Damage: External Cardiac Massage: Sacrum (Figures 10 to 12):

Lateral Surface of the Sacrum (Fig. 11A):

Sacral Canal:

As the sternum contains the marrow, it is used for taking a sample of marrow for the purpose of biopsy in obscure anaemias. Sternal splitting incision is given for the approach to the heart for cardiac surgery. Fracture of the sternum causes myocardial damage releasing the intracardiac enzymes, such as cretinine-K in the blood. Estimation of these enzymes gives an idea about the degree of the cardiac damage. Vigorous external cardiac massage can cause fracture of the sternum as the heart is forcefully compressed between the body of sternum infront and the 5 to 8 thoracic vertebrae behind. Sacrum is a triangular bone formed by union of five sacral vertebrae. Its base is directed upwards. It presents sacral promontory anteriorly, area for articulation with 5th lumbar vertebra in the middle and upper opening of the sacral canal posteriorly. Situated on either side of the opening of the sacral canal posteriorly are superior articular processes. Lateral part of the base on either side is known as ala of the sacrum. Ala of the sacrum is formed by the fusion of costal and transverse elements. Anterior surface gives origin to the piriformis muscle from 2nd, 3rd and the 4th segments classically representing the letter “E” (Figure 10). The auricular area meant for the hip bone is above. It forms the sacroiliac joint. The part behind the auricular area is rough and provides an attachment to the interosseous sacroiliac ligament. The narrow part of the lateral surface above the inferolateral angle gives origin to the gluteus maximus muscle and attachments to the sacrotuberous and the sacrospinous ligaments. In addition to this it gives origin of the coccygeous muscle. Infero-lateral angle of the sacrum provides attachment for the sacro-coccygeal ligament. The upper opening of the sacral canal is triangular and is directed upwards and backwards. Meninges end at the second sacral. Sacral

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Figure 10 Showing anterior aspect of the sacrum

Figure 11A Showing dorsal view of sacrum

Figure 11B Showing lateral surface of sacrum

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Figure 12 Showing base of sacrum (female)

nerves and the filum terminale pier the dura and lie free in the extradural space. In caudal block anesthesia it is extra-dural space which is injected with the anesthetic solution through the sacral hiatus. Anterior longitudinal ligament ends at the sacral promontory. Anterior surface of the sacrum has four sacral foramina for the four sacral nerves. The surface is also known as the ventral surface of the sacrum which shows concavity anteriorly. It forms the main part of the rectal bed. Apex of the sacrum articulates with the coccyx which is made of four ill-developed vertebrae. Apex of the sacrum if viewed from behind presents the sacral hiatus (Figure 11). Three structures pass through it. They are as under: C - First Coccygeal nerve. S - 5th Sacral nerve. F - Filum terminale. Dorsal surface of the sacrum is rough and presents median sacral and lateral sacral crests with four posterior sacral foramina. It gives origin to erector spini and the multifidus muscle.

CLINICAL Spondylolisthesis:

Lumbar Canal Stenosis:

Spina Bifida

Cauda-equina

Articular surface of the base of the sacrum has tendency to go forward with an angle of 30°. Due to the anterior slope of the articular surface of the base of sacrum, the fifth lumbar vertebrae has an inclination to slip forwards over the sacrum. This is basically due to the defect of the pericle, which allows body of fifth lumbar to go forward. Lumbar canal gets narrowed due to the hypertrophy of ligaments and bones as a part of the degenerative process. Patient has backache and intermittent claudication. He walks for some distance, stops due to pain, which gets relieved. He starts walking again and stops due to appearance of pain once more. It is a typical case of spinal canal stenosis and can be differentiated from prolapse of the lumbar, inter-vertebral disc. There is non-union of two halves of the neural called as meningeal. When examined with a source of light, such as torch, trans-illumination is positive. When the child cries, the swelling becomes tense. Presence of spinal cord in hernial sac, it is called meningomyelosis. It presents with saddle anesthesia and analgesia characterized by loss of control of bladder and sphincters with impotense. Sacralization of 5th lumbar or lumbarization of 1st sacral. Sacro-iliac strain: It is seen after delivery in women, due to laxity of ligaments of sacro-iliac joints.

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Sex Difference in the Sacrum (Figures 12 and 13):

Sacrum is wider and shorter in female. The anterior concavity of the sacrum is more prominent in female and the auricular surface meant for the hip bone forming sacroiliac joint is smaller. The most important point to differentiate between the male and female sacrum is the transverse diameter of the body of the first sacrum vertebra. It is equal to the width of the ala in female. However, in the male the transverse diameter is larger than the diameter of the ala.

Figure 13 Showing base of sacrum (male)

The subarachnoid space which contains cerebrospinal fluid ends at the second sacral. Dorsal surface is rough and presents four posterior sacral foramina on either side and fused spines appear as rough tubercles in the midline. Breadth of sacral base Sacral Index: ——————————————————————— × 100 Length of sacrum from promontory to the tip

Coccyx (Figure 14):

Normal sacral index is more in female than in male (Female-115, Male –105). Coccyx is formed by fusion of the four ill-defined vertebrae. It runs forwards and downwards from the apex of the sacrum. Filum terminale is attached to the dorsal surface of the 1st coccygeal vertebra. Fifth sacral foramen lies between 5th sacral and coccyx. It gives passage to the 5th sacral and the first coccygeal nerves.

Figure 14 Showing coccyx

Coccydynia:

Pain in the coccyx is known as coccydynia. It can be relieved by giving local injection of hydro-cortisone.

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PELVIS

Division of Pelvis: Boundaries of the True Pelvis (Lesser Pelvis) (Figures 15 and 19):

Muscles of the Pelvic Walls: Pelvic Inlet (Figure 18): Pelvic Outlet (Figure 18):

Pelvic Floor:

Direction of the Pelvic Cavity (Figure 21):

Contents of the Pelvic Cavity in Male: Contents of the Pelvic Cavity in Female:

Bony pelvis is formed by two hip bones which articulate directly infront and through the intervention of sacrum behind. Four bones take part in the formation of the pelvis as under: 1. Two hip bones 2. Sacrum 3. Coccyx It is divided into the greater pelvic and the lesser by the line running from sacral promontory to the symphysis pubis. Above the line is the greater pelvis, and below the lesser. True pelvis is bounded infront by the symphysis pubis, behind by the sacrum and coccyx and laterally the conjoint ramii of ischium and the pubis and the part of the ilium. The muscles and the ligaments help to form the true pelvic cavity. Obturater internus muscle forms the lateral wall leaving the gap for the obturator canal along with obturator fascia. Sacrotuberous and sacrospinus ligaments convert the greater lesser and the sciatic notches into the foramina. 1. Lateral wall of the true pelvic cavity is formed by the obturator internus muscle and the obturator fascia. 2. Posterior wall is formed by piriformis muscle and the fascia. The line of pelvic inlet runs from the sacral promontory to the pubic tubercle along the arcuate line making an angle of 50 to 60 degrees with the horizontal plane. Pelvic outlet is rhomboid in shape and is bounded by the symphysis pubis infront and the mobile tip of coccyx behind. Laterally it is bounded by ischial tuberosities. Anterolaterally conjoint rami of pubis and ischium posterolaterally the sacrotuberous ligaments are the boundaries. Pelvic floor is like an inverted tent of a circus sloping downwards leading to the hiatus ment for the passage of rectum, urethra and the vagina. The simile of the pelvic floor to the inverted umbrella is not apt as the top of the umbrella does not have the hiatus. Levator ani and the coccygeus muscles form the pelvic floor. Pelvic cavity is separated from the abdominal cavity by means of the pelvic brim. It is directed downwards, backwards, downwars and forwards. The anterior wall of the true pelvic cavity is only 5 cm while the posterior is three times more i.e. 15 cm. Pelvic cavity in female is longer. 1. Urinary bladder behind the symphysis pubis. 2. Rectum in front of the sacrum. Middle part is occupied by the prostate, seminal vesical, vas deferens and the ureters of either side. Urinary bladder is placed anteriorly behind the symphysis pubis. Rectum lies infront in the hollow of the sacrum and the middle part is occupied by vagina, cervix, uterus, uterine tubes and the ovaries. Many structures pass through the pelvic brim.

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Figure 15 Showing male pelvis

Figure 16 Showing female pelvis

Figure 17 Showing pictorial differences between male and the female pelvis

Pelvis Figure 18 Showing planes of pelvis

Figure 19 Showing ligaments of pelvis as seen from behind

Figure 20 Note: that the transverse diameter of inlet and the anteroposterior diameter of the outlet are the same that is 12.5 cm

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Figure 21 Showing dimensions of bony pelvic inlet, outlet and the cavity

Structures entering the pelvic cavity from medial to lateral side: 1. Median sacral vessels 2. Sympathetic trunk 3. Lumbo-sacral trunk 4. Obturator nerve 5. Internal iliac vessels 6. Superior rectal vessels 7. Sigmoid colon on the left 8. Ureter 9. Testicular or ovarian vessels 10. Vas deferens in males. 11. Right limb of the pelvic mesacolon on the left. 12. Median umbilical ligament 13. Lateral umbilical ligament 14. Lymphatics Functions of pelvis: 1. Protection 2. Weight transmission 3. Helps in walking 4. Supports birth canal A small dimple in the gluteal region is seen and can be felt which is at the second sacral. It is the site of the posterior superior iliac spine. It is an important landmark as it indicates the center of the sacroiliac joint and the end of the dural canal which lies at the level of second sacral vertebra. Differences between male and female pelvis (Figures 15 and 16) Male Pelvis

Female Pelvis

1.

Stronger

Less Stronger

2.

Narrow

Wider and shallow

3.

Sub-pubic angle is less, almost equal to the distance of middle and index fingers when spread.

Sub-pubic angle is around 90° equal to the angle made by the extended thumb and index.

Pictorial differences between the male and female pelvis showing in Figure 17. Pelvic measurements are mainly of obstetrical value. Outlet of the pelvis is rhomboid in shape and its transverse diameter is the distance between ischial tuberosities, while the antero-posterior diameter of the outlet is measured from the symphysis pubis to the tip of the coccyx.

Pelvis Diagonal Conjugate (Figure 17):

Diagonal conjugate is the distance from the lower border of the symphysis to the sacral promontory. Normally it is 12.5 cm. Tip of the index cannot reach the promontory in the normal pelvis. Some details of the differences between the male and the female pelvis. Male

Female

False pelvis

Is deep in Male

Is shallow in female

Inlet

Heart shaped

Oval

Ist sacral vertebra

Pelvic Injuries:

Types of Pelvis:

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Long segment of a short cone

Short segment of a long cone.

It is nearly ½ of the width of the sacral base

It is 1/3rd of the base.

Note : The transverse diameter of the inlet of the pelvis is 12.5 cm equal to that of the antero-posterior diameter of the pelvic outlet, i.e. 12.5 cm and equal is the diagonal conjugate (Figure 20). TAD = 12.5 cm (T– Transverse, A–Antero-posterior, D–Diagonal). One should remember TAD for memorizing the important diameters of the pelvis, as all three are equal i.e. 12.5 cm Apart from the fractures and dislocations of the hip and symphysis pubis, injuries of the internal organs such as the bladder, urethra and the rectum are important. Injury to the sacroiliac joint with displacement ruptures the ilio-lumbar branch of the posterior division of the internal iliac artery may lead to fatal extra-peritoneal haemorrhage. When the pelvis gets fractured at two places the pelvic organs are displaced. Head of the femur may penetrate the acetabular cavity and enters the pelvis i.e. central dislocation. 1. Gynacoid 2. Android 3. Platy pelloid 4. Anthropoid

CLINICAL Caudal (Sacral) Anaesthesia:

Pudendal Block:

Planes of Pelvis: Plane of Inlet: Plane of Outlet: Digonal Conjugate

Caudal block is given through the sacral hiatus. Needle passes through the skin and the posterior-sacro-coccygeal ligament. Anaesthetic fluid enters the extra-dural space and surrounds the spinal roots coming out of the dural sheath. It is given for painless labour (Figure 22). Pudendal block was commonly given for forcep delivery. A long needle is inserted through the vaginal wall after feeling the ischial spine, the anaesthetic solution is injected. Loss of anal reflex is the proof of bilateral successful pudendal block. Please study the Figures 18 and 21 carefully for the group of pelvic measurements. It runs from the superior border of symphysis pubis to the promontory. It runs from the tip of coccyx to the lower part of symphysis pubis. It is the most important measurement commonly used in obstetric. Normally one cannot reach promontory per vaginally. If one does, it is an indication of an abnormal pelvis. Pelvic measurements are of clinically importance in obstetrics. However, its value is undisputed in medicolegal sciences.

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Figure 22 Showing termination of dural sheath at second sacral and sacral hiatus

Figure 23 Showing gluteal region second sacral, the dimple and the spine

Figure 24 Showing different types of bony pelvis

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THORAX Introduction:

Functions of the Thorax (Figure 25):

Thorax is the part of the trunk between the abdomen below and the neck above. It is separated from the abdominal cavity by the respiratory diaphragm. Thoracic trauma is responsible for 70% deaths due to motorcycle accidents. 1. Thorax it is the home for the lungs, heart and great blood vessels. 2. Protections of cardio-respiratory unit. 3. Its main character is the elasticity, recoil and capacity to change the dimensions for respiration. If several ribs are fractured on one side or the other, the fractured segment of the thoracic wall gets isolated and moves paradoxically. It moves inwards during inspiration and outwards during expiration affecting the oxygenation of the blood. It can be treated by stablising the unstable part of the chest wall by fixing with wires. Endotracheal intubation with positive pressure respiration is an ideal treatment. 4. Thorax protects the upper abdominal organs under the sub-costal arches, liver being under the right and the spleen under left wings.

Figure 25 Showing bones forming thoracic cage

Shape of Thorax (Figures 26 to 28):

Thorax is broad below and narrow above. It is certainly not with the purpose of adjusting the shoulders. It is in conformity with size at the neck above and the abdomen below. Normal shape of the thorax in an infant is circular and oval in adults. In quadrupeds its antero-posterier diameter is more than the transverse diameter. Abnormal shape of the thorax is basically due to the diseases of the bones including the vertebral column. 1. Raised sternum like a keel (the pigeon chest.) 2. Depressed sternum like the pectus-excavatum Shape of the thorax in infant being circular and there is hardly any scope for increasing the radius. Therefore the respiration in infants is abdominal. Shape of thorax in adult is oval hence, there is a scope for increasing the diameter of the thoracic cage. In adults the respiration is thoracic and abdominal while in infants it is purely abdominal, due to the circular shape of the chest and the horizontal position of the ribs.

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Figure 26 Showing attachments of costal cartilages to the sternum from 1 to 7. Subcostal arch is formed by the 7,8,9,10,11 and the 12 rib are shown with free ends

Figure 27 Showing structures forming thoracic cage sagittal section. Note that it is roofed by the suprapleural membrane and floored by the diaphragm

Figure 28 Reduction of the upper part to the thorax is not with a purpose of accommodating the shoulders but it is in comformity with the size of the neck

Thorax Boundaries of the Thoracic Cage:

Mechanism of Respiration (Figures 29 to 32):

Summary:

Figure 29 Diaphragm goes down and increases vertical space of thorax

Figure 30 Showing increase in anteroposterior diameter due to raising of the rib from the oblique position

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Anteriorly it is bounded by the sternum and the costal cartilages, posteriorly by the twelve thoracic vertebrae and antero-postero-laterally by the ribs. The rib which directly articulates with the sternum is known the true rib and one which does not articulate directly with the sternum is known as the false rib. Ribs from 1 to 7 are true, 8 to 10 are false and 11th and 12th are floating. Thorax is roofed by the supra-pleural membrane and its floored by the respiratory diaphragm. Rib articulates with the body and the transverse process of the vertebra posteriorly. As the first rib and the sternum are raised as a unit, the antero-posterior diameter of the thorax increases (Pump handle or sternal pump). 1. The raising of the rest of the ribs follows the raising of the first. 2. Due to rotation of the ribs along the costo-vertebral axis, the ribs undergo a bucket handle movement which increases the transverse diameter of the thorax. 3. Movement of the diaphragm during inspiration changes the vertical dimension of the thoracic cage. Raising, rotation and the depression are involved in the mechanism of respiration. 1. Raising of the ribs from oblique to the horizontal position increases the antero-posterior diameter.

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Figure 31 Showing bucket handle movement of the rib increases side to side diameter of thorax

Figure 32 Showing raising of sternum and 1st rib which increases the antero-posterior diameter of thorax. 2 to 7 ribs follow the 1st rib

Clinical:

2. Rotation of the ribs increases the transverse diameter of the thorax 3. Depression of the diaphragm increase the vertical diameter. Note : Although the intercostal muscles are credited with movements of respiration, it appears that their main function is to resist an atmospheric pressure. However, I intend to mention the role of muscles in respiration as under: During inspiration the diaphragm and the intercostal muscles work. However, the expiration is the result of elastic recoil of the pulmonary alveoli and the thoracic cage. During forced breathing the inspiration is activated by the diaphragm, intercostal muscles, sternocleidomastoids, scleni, i.e. anterior, middle and the posterior, seratus anterior, pectoralis minor, erecter spinae and the muscle of the nose the alaequaenasi which is the muscle of the external nasal aperture. It is interesting to note that the forced respiration is by the muscles of the abdominal wall along with the latissimus dorsi. Difficulty in breathing is known as dyspnoea and it is a common sight that the patient of a bronchial asthama feels comfortable while seating, bending forwards and fixing arms to the chair. As the patient holds the chair the arms are fixed which fixes the scapulae and allows the pectoralis major and the serratus anterior to contract effectively. The movements of the diaphragm are partly controlled by the movements of the muscles

Thorax

The Body Wall:

Thoracic Wall (Figure 33):

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of the anterior abdominal wall. The height of the diaphragm is at the top when the patient is lying supine. This makes the patient breathless. As the patient sits the diaphragm goes down and the patient feels comfortable. Skin of the body wall is thin in front and thick behind. Cleavage lines of the trunk are arranged horizontally around the body wall. Incisions along the lines, heal earlier without scar formation. Incisions given across the cleavage lines heal with scar formation (Keloids). Keloid is not a hypertrophid scar but a new growth. The sternum, costal cartilages, twelve pairs of ribs and twelve thoracic vertebrae form the skeleton of the thoracic cage. Thoracic cavity is roofed by the suprapleural membrane and floored by the great muscular partition between the abdomen and thorax, the diaphragm. Some abdominal organs, such as liver, spleen and kidneys though lie in the abdomen proper, are protected by the ribs by the sub-costal arches.

Figure 33 Showing section of thoracic wall

Muscles (Figures 35 to 37):

They are as under : 1. External intercostal, 2. Internal intercostal, 3. Transversus thoracic. (Intercostal intimus) 1. External intercostal: It extends from the vertebral end posteriorly to the costal end anteriorly. Anteriorly it is replaced by the anterior intercostal membrane. Fibres are directed forwards, downwards and medially from floor of the subcostal groove of the rib above to the upper border of the rib below (Figures 37 and 38). 2. Internal intercostal: This muscle extends anteriorly up to the lateral border of the sternum and is replaced posteriorly by the posterior intercostal membrane. Fibres are directed backwards downwards and laterally from the floor of the subcostal groove of the rib above to the upper border of the rib below. Note : The fibres of the external and the internal intercostal muscles cross each other at right angle (Figures 37 and 38). Action and nerve supply: Both act as elevators of the ribs. They are supplied by corresponding intercostal nerves. 3. Transversus thoracic: It corresponds to the transverses abdominis muscle of the abdominal wall. It is exhibited in three different forms: 1) Subcostalis, 2) Intercostal intimi, and 3) Sternocostalis.

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Figure 34 Showing intercostal space with vessels and nerve. Vertical section of typical intercostal space is shown separately below

Figure 35 Showing intercostal space and intercostal vessels

Figure 36 Typical intercostal space

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Figure 37 Showing intercostal muscles

Figure 38 Showing intercostal spaces with intercostal muscles and membranes

Subcostalis: Intercostalis Intimus:

Sternocostalis (Figure 39) Intercostal Nerve (Figures 34, 40 and 41)

Figure 39 Showing sterno-costalis muscle (viewed from inside)

They are present only in the lower part and cover the inner aspect of the ribs from their tubercules to the angles. Absent or poorly developed in the first or second spaces, but is well developed in the lower spaces. In each space this muscle is partly fused with the corresponding internal intercostal inferiorly. Superiorly it is attached to the inner surface of the rib, above the subcostal groove. It arises from the back of the lower part of the sternum and gets inserted into the costal cartilges of the sixth to second ribs. It acts as the depressor of the costal cartilages. It is an anterior primary ramus of the thoracic nerve. Intercostal nerve emerges from the intervertebral foramen lies between the posterior intercostal membrane and the pleura. Next it lies between the internal intercostal and the intimus. As it comes to the anterior end of the

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Figure 40 Showing typical thoracic spinal nerve and its ventral division which forms the intercostal nerve

Figure 41 Showing course of intercostal nerve and its cutaneous branches

Internal Thoracic Mammary Artery (Figures 42 to 45):

intercostalis intimus it runs medially on the pleura from which it is separated by the sternocostalis muscle. It crosses in front of internal thoracic mammary artery, turns forwards and pierces the internal intercostal muscle, anterior intercostal membrane and the pectoralis major muscle to supply the skin. First intercostal being small fails to give cutaneous branches (skin over the first intercostal space is supplied by the supraclavicular nerves). Each intercostal nerve gives the lateral cutaneous branch which appears at the midaxillary line and divides into anterior and posterior branches. Lateral cutaneous branch of the second intercostal nerve is distributed to the skin of floor of the axilla and the upper arm (Intercostobrachial nerve). Lower five intercostal nerves cross the subcostal arch and enter the anterior abdominal wall. It arises in the neck from the first part of the subclavian artery. 2 cm above the sternal end of the clavicle opposite the origin of the thyrocervical trunk. It descends vertically downwards on the pleura and behind the termination of the subclavian vein, costal cartilages and the intercostal nerves, 1 cm lateral to the sternum. The artery is crossed

Thorax Figure 42 Showing anastomosis of superior and inferior epigastric arteries. Please note—The musculophrenic as one of the two terminal branches of the internal thoracic mammary artery of the right

Figure 43 Showing internal thoracic artery, origin and termination

Figure 44 Showing the course and relations of internal thoracic mammary artery

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Figure 45 Showing internal thoracic mammary artery and its terminal branches (diagrammatic)

Clinical:

by the phrenic nerves from lateral to medial side superficially. As it reaches the anterior end of the sixth rib it divides into musculo-phrenic and the superior epigastric arteries. Superior epigastric artery descends behind the rectus abdominis muscle to anastomose with the inferior epigastric artery. Musculophrenic artery runs laterally behind the subcostal arch and supplies the diaphragm and the intercostal muscles. Internal thoracic mammary artery gives the branch known as pericardiophrenic which accompanies the phrenic nerve. Internal thoracic mammary artery gives perforating branches for upper six spaces. In case of female, second and third perforating arteries are larger as they supply the mammary gland. Internal thoracic mammary artery supplies pleura, pericardium, mediastinal lymph nodes and the remains of the thymus. It is accompanied by the chain of lymph nodes and venae comitantes which unite to form the single vein medial to the artery at the level of third costal cartilage. It is separated from the lung and the pleura by means of fascia above and transversus muscle below. The left internal thoracic mammary artery is commonly used for the coronary by-pass. It is preferred for two reasons: 1. Nearness to the heart. 2. Tendency of not getting blocked, probably due to the presence of rich elastic tissue in the wall.

MEDIASTINUM Introduction:

Mediastinum is not the space but the broad fibro-areolar septum situated in the middle of the thorax. Antero-posteriorly it extends from the sternum in-front to the vertebral column behind. Vertically, it extends from the thoracic inlet above to the diaphragm below. It is pliable, mobile and dialatable. All the structures are packed inside among the loose areolar tissue.

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Mediastinum should not be described in isolation of the neck for the following reasons. 1. Longus coli muscle ends at the level of lower border of the third thoracic vertebra. 2. Pre-vertebral fascia which covers the longus coli muscle ends at the lower border of the third thoracic vertebra. 3. Sternothyroid and sternohyoid muscles take origin from the posterior surface of the manubrium sterni, which forms the anterior wall of the superior mediastinum. 4. Thoracic inlet acts as the gate of entry and the exit for the important structures of the mediastinum. It is also known as thoracic outlet, and some authorities have described thoracic outlet syndrome in which lower trunk of the brachial plexus and the subclavian artery are compressed between the first rib and the clavicle, leading to neurovascular symptoms. Figure 46 Showing mediastinum in horizontal section

Clinical:

Divisions of the Mediastinum (Figures 47 and 48)

A. Gate of entry for the following: i. Trachea ii. Oesophagus iii. Superior vena cava iv. Phrenic nerves v. Vagi vi. Sympathetic chains vii. Internal thoracic mammary arteries. B. Gate of exit for the following: i. Brachiocephalic artery ii. Left common carotid artery iii. Left subclavian artery iv. Thoracic duct v. Left recurrent laryngeal nerve In tuberculosis of the cervical vertebrae pus stops at T3 as the prevertebral fascia ends there. Pretracheal fascia descends in the superior mediastinum and fuses with the walls of the great blood vessels. Retropharyngeal infection can spread down to the posterior mediastinum up to the diaphragm. Cervical infection can cause infection of the mediastinum (mediastinitis). Mediastinum is divided into the superior and the inferior, by an imaginary line running from sternal angle of Louis to the lower border of the fourth thoracic vertebra. Inferior mediastinus is further divided into the anterior, middle and the posterior.

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Figure 47 Showing divisions of mediastinum (sagittal section)

Figure 48 Showing arch of aorta in superior mediastinum

Superior Mediastinum: Limits of Superior Mediastinum:

Contents (Figures 49 and 50):

Superior mediastinum lies above the line joining the sternal angle of Louis and the lower border of the fourth thoracic vertebra. i. Anterior – manubrium sterni ii. Posterior – upper four thoracic vertebrae iii. Superior – plain of the thoracic inlet. iv. Inferior – an imaginary line running from sternal angle of Louis to the lower border of fourth thoracic vertebra. v. Right - mediastinal pleura. vi. Left – mediastinal pleura. Note : Right and left limits are in fact the mediastinal pleurae and pleural spaces i. Tubes a. Trachea b. Oesophagus ii. Muscles a. Sternohyoid b. Sternothyroid c. Longus colii. iii. Arteries a. Arch of aorta b. Brachiocephalic artery c. Left common carotid artery d. Left subclavian artery

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Figure 49 Showing important contents of the superior mediastinum

Figure 50 Showing relations of the trachea in the superior mediastinum

e. Posterior intercostal arteries of upper four intercostals spaces. (First two intercostals spaces receive branches from costo-cervical trunk which is branch of the second part of the subclavian artery.) f. Internal mammary thoracic artery – the branch of first part of subclavian artery. iv. Veins: a. Right brachiocephalic vein b) Left brachiocephalic vein c) Superior vena cava d) Azygos vein. e) First left posterior intercostal vein f) Left superior intercostal vein. v. Nerves: (Figures 51 to 56) a. Vagii b. Phrenic nerves c. Left recurrent laryngeal nerve as the right recurrent laryngeal arises in the neck. d. Superficial and deep cardiac plexuses. vi. Organ: a. Thymus. Note: In case of laryngoptosis, larynx lies lower down in the neck and forms a part of the contents of the superior mediastinum. Figure 51 Showing some of the structures in the superior mediastinum

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Figure 52 Showing structures in the superior mediastinum. Please note the relations of the right pulmonary artery to the superior vena cava and ascending aorta

Figure 53 Showing transverse section of superior mediastinum at T 3 seen from above

Figure 54 Horizontal section of superior mediastinum above the arch of aorta (seen from above)

Figure 55 Showing structures in superior mediastinum

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Figure 56 Showing horizontal section of thorax at the level of 3rd thoracic vertebra as seen from above

Clinical :

Anterior Mediastinum

Contents :

Middle Mediastinum

Contents:

1. Cervical infection can extend into the mediastinum due to the arrangement of the deep fascia of neck. 2. Due to the presence of the loose areolar tissue and collapsible veins tumors of the mediastinum get well accommodated and has space to grow. 3. Superior mediastinum has collapsible veins on right and the resistant arteries on the left. Due to this the neoplasms (tumors) have tendency to follow the path of least resistance i.e. to the right. 4. In bronchiogenic carcinoma, paratracheal and bronchial lymph-nodes are involved. 5. Thyrothymic ligament connects the lower pole of the left lobe of thyroid to the thymus. The ligament has lymphatics through which cancer of the thyroid can spread to the superior and the anterior mediastinum. Limits : Anterior body of the sternum Posterior pericardium Superior line joining the sternal angle of Louis to the lower border of fourth thoracic vertebra. Inferior diaphragm Right right mediastinum pleura Left left mediastinum pleura 1. Anterior margins of the lungs and pleural recesses. 2. Lymph-nodes 3. Internal thoracic mammary arteries and its branches with accompanying veins. 4. Part of thymus. 5. Sterno-pericardial ligaments superior and the inferior. Limits : (Figures 57 to 59) Anterior anterior mediastinum Posterior posterior mediastinum Right right mediasternal pleura Left left mediasternal pleura 1. Heart and pericardium 2. Ascending aorta 3. Pulmonary trunk with two pulmonary arteries. 4. Lower part of superior vena cava. 5. Azygos veins 6. Phrenic nerves

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Figure 57 Horizontal section at the level of fifth thoracic vertebra seen from above

Figure 58 Middle mediastinum viewed from behind

Figure 59 Showing structures in the middle mediastinum viewed from the front

Posterior Mediastinum

Contents (Figure 60):

Clinical:

7. Bifurcation of the trachea with right and left bronchi. 8. Deep cardiac plexus. 9. Tracheobronchial lymph nodes Limits : Anterior middle mediastinum Posterior vertebral column Right right mediastinum pleura Left left mediastinum pleura 1. Thoracic part of the oesophagus 2. Descending thoracic aorta and its branches 3. Azygos vein, hemiazygos veins and accessory hemiazygos vein. 4. Vagii 5. Sympathetic chains with greater, lesser and the least splanchnic nerves. 1. Neurofibroma and ganglio-neuroma They arise in the posterior mediastinum respectively from intercostal nerve and the sympathetic chain. Tumors of the nerve sheath and the fibers present as neurofibroma (von Recklinghausen’s disease). Extension of the

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Figure 60 Showing structures in posterior mediastinum and at the left supraclavicular region

Effects:

Mediastinal Shift:

Mediastinitis:

Mediastinoscopy:

neurofibroma in the vertebral canal through the intervertebral foramen is known as dum-bell tumour. The tumour may produce symptoms of spinal cord compression for which it is removed by widening the intervertebral foramen in order to approach the vertebral canal. 2. Mediastinal compression syndrome: The syndrome is caused by tumors of thymus, thyroid, bronchiogenic carcinoma, Hodgkin’s disease, pericardial cysts, neurofibromas and ganglio-neuromas. It leads to congestion and dilatation of the veins of the arm due to obstruction of superior vena cava on the affected side. Oesophageal compression leads to dysphagia, tracheal cause to cough, pressure on left recurrent laryngeal nerve causes hoarseness of voice and phrenic nerve compression may cause to paralysis of diaphragm (Hemi diaphragm). Mediastinum is mobile and can change its transverse and vertical diameters due to respiratory movements of the diaphragm. This can be seen in X-ray screening. In case of pneumothorax of the left side, mediastinum is shifted to the right. Clinically it can be assessed by palpating the trachea in the supra-sternal notch. Extreme degree of mediastinal shift can affect the normal cardio-pulmonary functions. An apex of the heart can be felt in the fifth intercostals space 9 cm away from the median plane of sternum. Infection of the mediastinum is known as mediastinitis. It results from infections of the neck, injuries of the chest wall and the internal organs such as the oesophagus. Perforation of the oesophagus was the common cause of mediastinitis following oesophageal endoscopy with a rigid endoscope. Post-esophageal endoscopy showing rise of temperature is suggestive mediastinitis. A small incision is made above the supra sternal notch and the endoscope is passed up to the tracheal bifurcation. Node biopsy can be obtained without opening the pleural space.

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MEDIASTINUM SEEN FROM THE LEFT AND THE RIGHT Introduction:

Mediastinum seen from the Right (Figure 61):

Figure 61 Showing mediastinum seen from the right

Mediastinum seen from the right is blue and that from the left is red. Right atrium, superior vena cava, inferior vena cava, and the azygos vein are the structures prominently seen on the right of the mediastinum. All of them contain venous blood which is conventionally shown in blue colour. Mediastinum seen from the right is red. Left ventricle, arch of aorta, descending thoracic aorta, left common carotid and the left subclavian arteries are structures prominently seen on the left of the mediastinum. All of them contain arterial blood which is conventionally shown in red colour. The blue and the red appearances of the right and left mediastinum correspond to the right and left chambers of the heart, right being venous and left arterial. Pulmonary ligament is in the centre surrounding the root of the right lung which runs downwards to the diaphragm. It contains two bronchi, eparterial and the hyparterial. In front of these lies the right pulmonary artery. The remaining space is occupied by the two pulmonary veins. Immediately above the root of the right lung is the trachea. The trachea is crossed by the vagus nerve obliquely as it goes posterior to the root of the right lung. In front of the trachea is the superior vena cava, followed by a right atrium in the middle and the inferior vena cava below. Right phrenic nerve runs in contact with the superior vena cava, right atrium and the inferior vena cava to enter an opening for the inferior vena cava. It is accompanied by the pericardiophrenic artery, branch of the internal thoracic mammary artery. Below and behind of the root of the right lung is the oesophagus. The azygos vein comes out of the under surface of the oesophagus and arches over the root of the right lung superiorly, crossing the trachea and the right vagus to join the superior vena cava at the level of right second costal cartilage. Behind the root of the lung

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Summary:

Mediastinum Seen from the Left (Figure 62):

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and by the side of the vertebral column, sympathetic chain is seen giving branches as under: 1. Greater splanchnic, (F5 to 9) 2. Lesser splanchnic and the (T 10 to 11) 3. Least splanchnic (T12) When the mediastinum is seen from the right following structures containing venous blood (blue) are seen. 1. Superior vena cava 2. Right atrium 3. Inferior vena cava 4. Azygos vein 5. Intercostal veins Pulmonary root is seen in the centre surrounded by the pulmonary ligament. At the root of the left lung there is only one bronchus and the pulmonary artery lies above the bronchus. Antero-inferior part of the root of the lung is occupied by the two pulmonary veins. Antero-inferior to the root of the left lung is the bulging of left ventricle. Arising from the left ventricle, arching over the root of the left lung is an arch of the aorta. Its ascending and descending parts can also be seen.

Figure 62 Showing mediastinum seen from the left

The arch of arota gives left common carotid and the left subclavian arteries. They are seen above the arch of aorta. Behind the left subclavian artery is the left border of the oesophagus, which accompanied by the thoracic duct. The gap between the left common carotid and the left subclavian arteries, crossing of the left vagus and the left phrenic is seen. The left vagus goes posteriorly behind the root of the left lung below the arch of aorta where it gives the left recurrent laryngeal nerve. The left phrenic nerve runs anterior to the root of the left lung and goes to the diaphragm. It is accompanied by pericardio-phrenic artery, the branch of internal thoracic mammary artery. Left superior intercostal vein is formed by the intercostal veins of the second and third intercostal spaces. As it goes anteriorly it crosses the aorta, and the vagus anteriorly and itself gets crossed by the left phrenic posteriorly. The left superior intercostal vein joins the left brachiocephalic vein above the arch of aorta. Sympathetic chain along with its three branches, i.e. greater, lesser and the least are seen by the side of the vertebral column.

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Summary:

Note:

When the mediastinum is seen from the left the following structures containing arterial blood (red) are seen. 1. Left ventricle 2. Arch of aorta 3. Descending thoracic aorta 4. Left common carotid artery 5. Left subclavian artery It is important to remember that the arch of aorta crosses the thoracic oesophagus from the front and goes the left behind as the descending thoracic aorta. In brief it forms anterior, left and the posterior relations of the oesophagus.

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PLEURA Pleura is the serous membrane which covers the visceral surface the lung and inner wall of the thorax. The layer covering the lung is known as visceral pleura and one which covers the thoracic wall is known as the parietal pleura. Parietal pleura is thicker than the visceral pleura and is covered by the endothoracic fascia from outside. Both the layers are continuous with each other at the root of the lung and project downwards as pulmonary ligament. There is a potential space between the parietal and the visceral layers of pleura. It is known as the pleural cavity or the pleural spaces. It contains little amount of fluid which reduces friction between the two layers of the pleura. Visceral layer of the pleura is adherent to the surface of the lung and also enters the fissures of the lung (Figure 63). Figure 63 Showing two layers of pleura and its relation with the lung

Parts of the pleura (Figure 64):

It is divided into 1. Cervical pleura 2. Costo-mediastinal pleura 3. Costo-diaphragmatic pleura 4. Mediastinal pleura 5. Costal pleura

Figure 64 Parts of parietal pleura

1. Cervical pleura (Figures 65, 70 and 71): Cervical pleura raises like a dome in the root of the neck. The line of reflection begins at the sternoclavicular joint with a convexity 3.75 cm upwards (1.5 inches) above the clavicle and comes down to the point of junction of the medial Figure 65 Showing different parts of the parietal pleura

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2.

3.

4.

5.

and the intermediate thirds of the clavicle. Due the obliquity of the first rib, cervical pleura is exposed anteriorly. It does not rise above the level of the neck of the first rib posteriorly. Cervical pleura is protected by the supra-pleural membrane which is known as Sibson’s fascia. Sibson’s fascia (Figures 73 and 77): Supra-pleural membrane is the triangular fibrous membrane situated at the root of the neck. Its base is directed downwards and laterally and the apex upwards and medially. Base is attached to the inner border of the first rib and the apex to the tip of the transverse process of the seventh cervical vertebra. Supra-pleural membrane protects the apex of the lung and prevents it from popping up during deep inspiration. Morphologically it is supposed to be a part of the scalenus pleurae muscle. It is also considered as the specialized thickened part of the endo-thoracic fascia by some authors. Costo-mediastinal line of pleural reflection (Figures 72, 74 and 76): Costomediastinal line of pleural reflection begins opposite the sternoclavicular joint and runs downwards and medially to the sternal angle (angle of Louis). Here it meets the costo-mediastinal line of pleural reflection of the opposite side in the midline. From here both the lines run together up to the level of the fourth costal cartilage where the left line deviates to the left about 3.5 cm to reach the left margin of the sternum and turns sharply downwards behind the fourth, fifth and the sixth costal cartilages. The area created by the deviation of the left costo-mediastinal line of pleural reflection presents as an area of superficial cardiac dullness. Here the heart lies in direct contact with the lower two pieces of sternum to the left. At the sixth costal cartilage the left line becomes continuous with the costo-diaphragmatic line of pleural reflection. On the right side the line of reflection runs downwards as far as the xiphoid process and comes below the sub-costal arch. It continues along the seventh costal cartilage and the rib, and joins the right costo-diaphragmatic line of reflection. Costo-diaphragmatic pleura (Figure 75): Costo-diaphragmatic pleura crosses the eighth rib at the mid-clavicular line and the tenth rib in the mid-axillary line. It ascends upwards and backwards crossing the eleventh and the twelfth ribs to reach the lower border of the twelfth thoracic vertebra. It crosses the twelfth rib at the lateral margin of the sacro-spinalis muscle. Crossing of the twelfth rib by the costodiaphragmatic line of reflection is important due to relation with the posterior surface of the kidney. During exposure of the kidney excision of the twelfth rib needs care to protect the pleural line and thereby the pleural space. Mediastinal pleura (Figures 66 to 69 and 75): Mediastinal pleura forms the lateral cover for the mediastinum and it pierced by the root of the lung. If the horizontal section of the root of the lung is examined, one can note that it is continuous with visceral pleura. Two layers hang from the root of the lung in the form of pulmonary ligament like a cuff of a long sleeved shirt. Costal pleura: Costal pleura covers the back of the sternum, ribs and the sides of the vertebral bodies. It is continuous with the cervical pleura above and the diaphragmatic pleura below and the mediastinal pleura medially.

Pleura Figure 66 Showing horizontal section of the lung passing through the root and the apex. Please note that the parietal and visceral pleura are continuous at the root of the lung

Figure 67 Showing horizontal section of the lung above the root

Figure 68 Showing lungs and diaphragm with pleural cavity and cardiac notch. Note the costodiaphragmatic recess

Figure 69 Showing pleural reflection and its relation with 12th rib lower down

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Figure 70 Showing surface marking of cervical pleural reflection

Figure 71 Showing sagittal section of apex of lung through scalenus anterior muscle

Figure 72 Showing superficial cardiac dullness

Figure 73 Showing suprapleural membrane protecting apex of the lung

Figure 74 Cervical and mediastinal line of pleural reflection

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Figure 75 Costodiaphragmatic recess

Figure 76 Showing lungs and cardiac notch of the anterior border of the left lung

Figure 77 Showing suprapleural membrane and lungs

Costo-diaphragmatic Recess of Pleural Cavity:

Role of Pleural Cavity in Respiration: Clinical:

Below the lower border of the lung, costal and diaphragmatic pleurae come into contact with each other. Lower border of the lung descends into this space during deep inspiration. This recess is 2.5 cm deep anteriorly, 5 cm posteriorly and 7.5 cm in the mid-axillary line. The space is related to the liver and the kidney on the right and the stomach and spleen on the left. Obliteration of the costo-diaphragmatic angle seen in the radiograph of the chest is the earliest sign of the presence of fluid in the pleural cavity. (Obliteration of the costo-diaphragmatic angle is the earlierst sign of pleural effusion). Negative pressure in the pleural cavity pulls the visceral pleura towards the parietal. When the negative pressure in the pleural cavity is transformed into the positive such as in pneumothorax the inherent property of the elastic recoil of the lung causes collapse. 1. Pleural effusion: Excessive amount of fluid in the pleural cavity is known as pleural effusion. Pleurisy is an inflammation of the parietal

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Various Types of Pneumothorax:

Treatment:

Blood Supply of the Pleura: Nerve Supply:

pleura which is supplied by somatic nerves and hence gives pain during respiration. The same nerves also supply the anterior abdominal wall which explains the radiation of the pain to the anterior abdominal wall in pleurisy. It may exhibit guarding and even the rigidity of the anterior abdominal wall which misguide the clinician. In India pleurisy due to tuberculosis is common. 2. Pneumothorax: Normally there is no air in the pleural cavity. Entry of air into the pleural cavity from the atmospheric air due to chest injury or from the lung following the damage, is known as pneumothorax. 3. Haemothorax: Blood in the pleural cavity is known as haemothorax. 4. Empyema: Pus in the pleural cavity is known as pyothorax. 5. Pleural abscess: Localised collection of the pus which gets isolated from the rest of the pleural cavity is known as pleural abscess. 6. Hydro-pneumothorax: Presence of fluid and the air in the pleural cavity is known as hydro-pneumothorax. 7. Chylothorax: Presence of the lymph in the pleural cavity is known as chylothorax. 8. Secondary tumours of the pleura: In malignancy of the mammary gland the parietal pleura can get involved secondarily leading to malignant pleural effusion which is invariably red in colour. 9. Primary tumours of the pleura: Mesothelioma is the most important malignant tumor of the pleura. In this condition patient has chest pain and dyspnoea. Diagnosis can be made by obtaining the pleural fluid through pleural aspiration and subject to it microscopic examination for evidence of malignant cells. 1. Open pneumothorax: When the air enters the pleural cavity and goes out with ease is known as open pneumothorax. 2. Tension pneumothorax: The air enters the pleural cavity but finds it difficult to leave due to the valvular opening in the chest wall. The damaged tissues at the opening in the chest wall acts like the flap valve. It is treated by under water seal drainage. 3. Spontaneous pneumothorax: It is commonly seen in young and thin men. It is due to the rupture of the apical blebs. 4. Iatrogenic pnemothorax: It may occur due to damage to the lung tissue by the procedure such as the pleural aspiration, liver biopsy or the lung biopsy. Note: Spontaneous pneumothorax has 30% chances of recurrence for which removal of the parietal pleura is an ideal treatment for preventing the recurrence of the pneumothorax. In the above procedure the lung surface gets adherent to the chest wall within four to five days. The treatment of the open pneumothorax is simple and mere tight closure of the opening in the chest wall is enough. The air trapped inside the pleural cavity gets absorbed in due course of time. In case of the treatment of the tension pneumothorax air is removed from the pleural cavity with the help of under water seal. Parietal pleura is supplied by the arteries of the thoracic wall. The anterior and the posterior intercostals, internal thoracic mammary arteries with their branches are the main sources of blood supply. The parietal pleura which is sensitive to pain, temperature and touch, which is carried through the spinothalamic track to the ventro-posterolateral nucleus of the thalamus. Visceral pleura is supplied by the autonomic nerves from the pulmonary plexus. It is sensitive to the stretch only.

Pleura Nerve Supply of Parietal Pleura:

Clinical:

405

1. Costal part by the intercostal nerves. 2. Mediastinal part by the phrenic nerves. 3. Pleura on the dome of diaphragm by the phrenic and the lower six intercostal nerves. Due to high hydrostatic pressure in the capillaries of the parietal pleura and the low osmotic pressure in the visceral, fluid produced by the parietal pleura is absorbed by the visceral. Increased production and poor absorption leads to accumulation of fluid in the pleural cavity. Normal amount of pleural fluid is 5-10 ml and can be detected clinically when it reaches the level of 300 ml. It interferes with lung expansion, leading to reduced air entry, which can be appreciated with the help of a stethoscope. Percussion gives stony dullness. Excessive amount pleural effusion on one side can lead to the mediastinal shift to the other. Removal of the pleural fluid is done through the eighth intercostals space in the mid-axillary line with the help of a needle. It is done under local anesthesia while the patient is sitting. The needle should go exactly in the middle of the intercostal space to protect the neurovascular bundle above and the collateral artery below. It can also be done in the posterior axillary line through the sixth intercostal space. The needle passes through following structures on its way to pleural cavity, from superficial to the deep. 1. Skin 2. Fascia 3. Serratus anterior. 4. Intercostal muscles, namely the external, internal and the intimus. 5. Endothoracic fascia 6. Costal pleura. Note: The process of removing fluid from the pleural cavity is known as thoracocentesis or pleurocentesis. Rapid and excessive removal of the fluid is not advised as it can cause reactionary pulmonary oedema.

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LUNGS

Weight: Base of the Right Lung:

Base of the Left Lung: Apex: Anterior Border:

Posterior Border:

Inferior Border: Costal Surface:

Medial Surface:

They are spongy elastic retractile, paired organs of respiration. It crepitates on pressure due to air inside. Each lung occupies the thoracic cavity on either side of the mediastinum. Heart with the pericardium is shifted towards the left which produces the deep cardiac notch, along the anterior border of the left lung. Volume and weight of the left lung is less than that of the right due to the cardiac notch. Due to the high right dome of diaphragm right lung is shorter than the left. Lung presents the base, an apex, costal surface, mediastinal surface, round posterior, sharp anterior and the inferior borders. At birth colour of the lung is pink but it becomes darker with the advancing of the age due to the deposition of the carbon which is more in male than in female. Lung of a stillborn is firmer in consistency and sinks in water. (Hydrostatic test which is of medico-legal importance). On the other hand, lung of an infant who has breathed is lighter in weight and does not sink in water. It crepitates on pressure due to the air inside. Right lung — 700 grams. Left lung — 600 grams. Base of the right lung lies on the right dome of diaphragm. Its margins are sharp and the base presents the concavity in the middle due to the high right dome of the diaphragm. It must be remembered that the right dome of the diaphragm separates the base of the right lung from the right lobe of the liver and the right kidney. Base of the left lung is separated from left lobe of liver, stomach and the spleen by the left dome of diaphragm, which is lower than the right. An apex of the lung is conical pointing upwards. It can be seen from the front due to obliquity of the first rib. An apex of the lung is protected by the supra-pleural membrane. (Sibson’s fascia). It is sharper and shorter than the posterior border. On the right anterior border of the right lung corresponds to the costo-mediastinal line of pleural reflection, while the anterior border of the left lung shows a wide cardiac notch. The notch lies below the fourth costal cartilage. The heart and the pericardium are not covered by the anterior border of the left lung. In this region heart and the pericardium lie in direct contact with the lower left part of the body of the sternum. (Area of superficial cardiac dullness). It is increased in pericardial effusion. Round posterior border of the lung separates the medial surface of the lung from the costal. It runs along the heads of the ribs from the seventh cervical to the tenth thoracic spines. Inferior border is circular and is at the base separating the base, costal and medial surfaces. Costal surface is the largest surface with the convexity pointing in-front, behind and laterally. It is covered with the visceral and the parietal pleurae and the pleural cavity. Comparative study of the mediastinum seen from the right and the left has already been done. It must be remembered that the same impressions are produced on the medial surfaces of the right and the left lungs.

Lungs Medial Surface of the Right Lung:

It is divided into two, mediastinal and the vertebral. Let us consider the vertebral part of the medial surfaces of the right and left lungs. Relations of the vertebral part of the medial surfaces of the right and the left lungs Right

Relations of the Mediastinal Surface of the Right Lung (Figure 78):

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Left

1. Vertebral bodies

1.

Descending thoracic aorta intervenes between the lung and the bodies of fourth to ninth thoracic vertebrae.

2. Heads of the ribs.

2.

Heads of the ribs.

3. Sympathetic chain and its branches

3.

Sympathetic chain and its branches

4. Intercostal vessels.

4.

Intercostal vessels.

The mediastinal surface of right lung presents the root of the lung in the centre covered with the pleural reflection from front, above, below and behind. This double fold of the pleura is known as the pulmonary ligament. It hangs down from the root of the lung above, to the diaphragm below.

Figure 78 Showing mediastinal surface of right lung

Above the root of the lung tracheal impression can be seen. It is crossed by the right vagus nerve which runs obliquely behind the root of the lung. Infront of the tracheal impression is the impression of the superior vena cava. In the lower part the inferior vena cava creates an impression infront of the root of the lung. The middle area has an impression produces by the right atrium. Right phrenic nerve runs along the superior vena cava, right atrium and the inferior vena cava successively downwards. Below and behind the root of the right lung is the esophageal impression. Impression of the azygos vein lies behind the oesophagus. The azygos vein comes out from the under surface of the oesophagus and arches over the root of the right lung by crossing the trachea and the right vagus nerve superficially. Azygos vein opens into the superior vena cava at the level of right second costal cartilage. Pericardio-phrenic artery, branch of the internal thoracic mammary artery accompanies the phrenic nerve. Note: We have already seen that the mediastinum viewed from the right is blue and that from the left is red. Following blue structures produce impressions on the mediastinal surface of the right lung.

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Mediastinal Surface of the Left Lung (Figure 79):

1. Superior vena cava 2. Right atrium 3. Inferior vena cava 4. Azygos vein. Mediastinal surface of the left lung presents the root with the pulmonary ligament. Below and in front of the root of the lung is the cardiac impression produced by the left ventricle. Immediately above this impression the left lung has an intimate contact with the pulmonary trunk and the arch of aorta. Arch of aorta is seen arching over the root of the left lung. Its two branches namely the left common carotid and the left sub-clavian arteries produce two vertical impressions above the aortic impression. The impression of the left common carotid artery is anterior to the impression of the left subclavian artery. Behind the impression for the left subclavian artery is an impression of the left border of the oesophagus. Thoracic duct runs along the left borders of the oesophagus.

Figure 79 Showing mediastinal surface of left lung

Lobes and Fissures of the Lungs:

Bronchopulmonary Segments (Figure 80):

The inter-arterial space situated above the arch of aorta is bounded infront by the left common carotid and behind by the left sub-clavian arteries, show crossing of the vagus and phrenic nerves. Vagus goes behind and the phrenic in front of the root of the left lung. Right lung has three lobes namely the superior, middle and the inferior divided by the two fissures, oblique and the transverse. Oblique fissure passes across the substance of the lung except at the hilum. It starts six centimeters below the apex of the lung runs obliquely downwards and forwards to reach the inferior border of the lung 5 cm away from the midline. Obliquity of the fissure divides lung into two major parts. Right lung has an additional fissure known as horizontal fissure. It runs along the fourth costal cartilage and joins the oblique fissure in the mid-axillary line. The left lung has two lobes. Occasionally reverse may occur, the left having three and right having two. Sometimes accessory lobe of the lung is present as a developmental anomaly. Due to the movements of the diaphragm during inspiration and expiration, lower part of the lung undergoes maximum expansion. It is the portion of the lung tissue supplied by the tertiary division of the bronchus. It is triangular in shape with an apex directed towards the hilum and the base towards the periphery of the lung. There is an intersegmental plane in between the two adjoining segments. This plane is marked by the presence of an inter-segmental vein, which acts as a guide

Lungs

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Figure 80 Bronchopulmonary segments of right and left lungs. Please note that the apical basal is most dependent segment commonly affected by aspiration pneumonia (Medelson syndrome)

for the operating surgeon. Intersegmental vein drains of both the segments lying side by side. On the other hand, air supply and blood supply of each segment is independent. Segments of the right and the left lungs are as under. Right

Left

A. Upper lobe a. Apical b. Posterior c. Anterior

A. Upper lobe a. Apical b. Posterior c. Anterior

B.

B.

Middle a. Medial b. Lateral

C. Lower lobe a. Apical b. Anterior basal c. Medial basal d. Lateral basal e. Posterior basal

Clinical (Figures 81 to 83 and 87):

Figure 81 Showing bronchopulmonary segment

Middle a. Superior b. Inferior

C. Lower lobe a. Apical b. Anterior basal c. Medial basal d. Lateral basal e. Posterior basal

Above chart illustrates that the left middle lobe presents the superior and the inferior, in place of the medial and the lateral like the right. It is because of the cardiac shift to the left, pushes the original lateral and the medial segments upwards so that the lateral becomes the superior and the medial inferior. Before the knowledge of the bronchopulmonary segments, for the diseases of the lung such as the tuberculosis, lung abscess, bronchiectasis, benign growths and cancer of the lung, whole lung was removed (Pneumonectomy). Later came the lobectomy. After the knowledge of

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Figure 82 Showing pulmonary unit

Figure 83 Showing bronchopulmonary segments as seen from the lateral side

Figure 84 How to assign a given lung to correct side. You can hold only left lung in left hand and right lung in right hand

the bronchopulmonary segments, the segmental resection of the lung has become practical and routine. Recently pulmonary angiography is done to diagnose the obscure causes of the disease of the lungs computerised pulmonary function test has become the basis of assessing lung functions. Peak flow meter is used to determine the lung capacity. Knowledge of bronchopulmonary segment has been very helpful in postural drainage.

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Figure 85 Showing bronchial arteries

Figure 86 Phrenic nerves have tendency to swing to the right. Left phrenic nerve crosses first part of subclavian artery while the right does not Note: First ribs are cut on both sides to show the structures behind

Figure 87 Showing bronchial tree with course of pus or fluid: (A) dependent apical basal segment and the area of its dullness at the back (inter scapular region) (B)

Phrenic Nerve– (Root value C4 and insignificant contribution from C2 and C5):

It is a mixed nerve where the motor and sensory fibers are in proportion of 2:1. It is formed at the lateral border of the scalenus anterior on the scalenus medius and lies undercover of the sternomastoid. It is virtually plastered to the surface of the scalenus anterior muscle by the prevertebral fascia. During its further course in the thorax both are accompanied by the pericardio-phrenic arteries which are the branches of the respective internal thoracic mammary artery. It is advisable to have a comparative study of the nerve of the right and the left.

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Note (see Figure 86):

It is interesting to note that both the phrenic nerves have a tendency to swing to the right, as a result of which the left phrenic nerve leaves the scalenus anterior muscle earlier and crosses the first part of the subclavian artery, while the right phrenic relaxes comfortably on the scalenus anterior muscle and hence, does not cross the right subclavian artery. This tendency of swing to the right is not restricted to the phrenics alone but the infection of swinging to the right is also picked up by the internal jugular veins. As the result of which the left internal jugular vein overlaps the left common carotid artery and the right internal jugular vein runs away from the right common carotid artery to the right. Right phrenic nerve

Left phrenic nerve

1. More deeply placed

1. Less deeply placed.

2. Shorter and vertical.

2. Longer.

3. Descends lower down on the . scalenus anterior

3. Leaves the muscle earlier.

4. No crossing of first part of subclavian artery.

4. Crosses the first part of the subclavian artery.

5. Lies lateral to the right brachiocephalic vein.

5. Lies behind the left brachio-cephalic vein.

6. Lies lateral to the superior vena cava

6. Lies between the left subclavian and the left common carotid arteries.

7. Comes in front of the root of the lung. 7. Comes in front of the root of the lung. 8. Related to the pericardium and the mediastinal pleura.

8. Related to the pericardium and the mediastinal pleura.

9. Related to right atrium.

9. Related to left ventricle.

10. Related to the lateral aspect of short intrathoracic part of inferior vena cava (IVC)

10. No such relation.

11. Not crossing of vagus.

11. Crosses superficial to the vagus.

12. No relation with arch of aorta.

12. Crosses the arch of the aorta.

13. Passes through the opening for the inferior vena cava in the diaphragm and enters the abdomen.

13. Pierces the diaphragm and enters the abdomen.

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TRACHEA Figure 88 Showing trachea

Length: Structure:

Trachea begins in the neck opposite the sixth cervical vertebra, where the larynx ends and the trachea begins, the level is the same where pharynx ends and the oesophagus begins. It enters the superior mediastinum and divides opposite the fourth thoracic or at the upper border of the fifth thoracic vertebra into two bronchi. The site of its bifurcation into right and the left bronchi lies a little to the right of the median plane explaining the tendency for the foreign body to go into the right bronchus (Figure 88). In cadaver (Males) – 4 to 4.5” (Females) – 4” – In the living the length is slightly more during the inspiratory phase. Presents the tracheal rings which are open posteriorly. However, the posterior wall which is flat lies in contact with the oesophagus, and has few smooth muscle fibres (Trachealis muscle). The cartilages of the larynx are mostly of the hyaline variety, hence, they have tendency to get calcified or ossified. On the other hand, the epiglottis, corneculate, cuniefied and the processes of the arytenoids are of yellow elastic variety hence, immune from calsification or ossification. Relations of the Trachea (Figure 89): Right

Left

1. Isthmus of thyroid on 2,3,4 tracheal rings

Anterior

Posterior Oesophagus

1

Right lobe of thyroid

Left lobe of thyroid

2. Inferior thyroid vein

Vertebrae

2

Right recurrent laryngeal nerve

Common carotid and left subclavian artery

3. Thyroidea ima artery

Longus coli muscle and prevertebral fascia up to T-3

3.

Right vagus

Arch of aorta

4. Arch of aorta with three branches

—

4.

Azygos vein

Left recurrent laryngeal nerve Contd...

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Posterior

Right

Left

5. Remains of thymus

—

5.

Brachiocephalic artery

Paratracheal nodes.

6. Left brachiocephalic vein

—

6.

Right pleura and lungs

Arch of aorta separates trachea from the left lung

7. Deep cardiac plexus

—

7

Paratracheal lymph nodes

8. Manubrium sterni with suprasternal notch

—

—

—

Figure 89 Showing relation of trachea

Blood Supply: Venous Drainage: Lymphatic Drainage: Nerve Supply:

It is supplied by inferior thyroid artery. Its veins drain into the brachio-cephalic veins. Drain into the paratracheal and the postero-inferior deep group of cervical nodes. It is supplied by the vagus and the recurrent laryngeal nerves.

BRONCHI Right Bronchus:

Left Bronchus:

Clinical:

It is wider, shorter and more in line with the trachea than the left. The angle it makes with the vertical plane is of 25 degrees. By virtue of its direction, foreign bodies from the upper respiratory tract has tendency to enter the right bronchus. Apart from this, the right bronchus divides before its entry into the right lung. The upper division which is situated above the pulmonary artery is known as the eparterial bronchus and the lower as the hyparterial bronchus. It is longer, narrower and makes an angle of 45° with the vertical plane. It does not divide until it enters the lung. Arch of aorta as it arches over the root of the left lung, forms superior and the posterior relations. Commonest cause of tracheal stenosis (narrowing) is after tracheostomy (making an opening in the trachea in case respiratory obstruction), other causes being enlarged thyroid, aortic aneurysm (localised dilatation of aorta) and enlarged lymph nodes.

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Vagus Nerve in Thorax (Figures 90 to 97)

Figure 90 Right vagus in the neck

Figure 91 Left vagus in the thorax with left recurrent laryngeal nerve

Figure 92 Showing crossing of left phrenic and vagus nerves

Right

Left

It enters the thorax and lies to the right of the trachea. It passes posterior to the root of the right lung

Enters the thorax, lies between the left common carotid and the left subclavian arteries where the left phrenic crosses it, reaching the posterior aspect of the root of the left lung

Crossed by azygos vein

Crossed by left superior intercostal vein and it crosses the arch of aorta

No recurrent laryngeal nerve in thorax

It gives left recurrent laryngeal nerve as it reaches the lower part of the arch of aorta

Posterior pulmonary plexus behind the root

Posterior pulmonary plexus behind the root

Takes part in the formation oesophageal plexus

Take part in the formation oesophageal plexus

Continues, after emerging from the plexus as the posterior gastric nerve

Continues, after emerging from the plexus as the anterior gastric nerve

Gives thoracic cardiac branch to the cardiac plexus

It is given by the left recurrent laryngeal nerve

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Figure 93 Transverse section of neck through the isthmus thyroid seen from above

Figure 94 Showing relations of trachea in the neck and the superior mediastinum

Figure 95 Showing thorax inlet (right)

Figure 96 Showing structures at thorcic inlet

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Figure 97 Showing recurrent laryngeal nerves of right and left. Note their vascular relations on the right and the left

Left Recurrent Laryngeal Nerve:

Note:

Figure 97A Showing development of arterial arches

Figure 97B Showing development of ligamentum arteriosum

It arises from the vagus as it crosses the arch of aorta. It hooks the ligamentum arteriosum, and the reaches the groove between the trachea and the oesophagus. It follows the left border of the oesophagus during its further course. The recurrent laryngeal nerves supply all the intrinsic muscle of the larynx except the cricothyroid which is the only intrinsic muscle lying outside and supplied by the external laryngeal nerve. It also supplies the mucus membrane of the larynx below the vocal cords. Recurrent laryngeal nerve is the nerve of 6th arch hence, lies caudal to the 6th arch. On the left the portion between pulmonary artery dorsal aorta does not disappear. It remains in the form of ductus arteriosus and which becomes the ligamentum arteriosum after birth following its closure.

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How to Assign a given Lung Correctly to its Appropriate Side (see Figure 84):

Histology of the Lung: Serous Coat: Areolar Tissue: Pulmonary Substance:

Phagocytic Cells:

Pulmonary Unit (Figure 82):

It prevents the left recurrent laryngeal nerve from going up in the neck, hence it hooks the ligamentum arteriosum directly and the arch of the aorta indirectly. Ductus arterious of right and 5th arch artery disappear allowing right recurrent laryngeal to go up in the neck. It lies caudal to the base of the right fourth arch artery. The base of the right fourth arch artery forms the first part of the right subclavian artery. Do not make the fissures and the number of lobes as the criteria for deciding the side. Keep the lung in such a way so that the apex points upwards, base downwards, thin anterior border anteriorly and the round posterior border posteriorly. Hold the lung in such a way, as shown in figure where the thumb covers the vertebral part of the medial surface, the fingers cover the costal surface like the ribs, and wide cleft between the thumb and the index holds the round posterior border. This way, one can hold only the right lung in the right hand and the left lung in the left hand. Three components, namely the serous coat, areolar tissue and pulmonary substance form the components of the lung tissue. Serous coat is the visceral pleura, which is adherent to the surface of the lung and covers the organ excepting near its root. Areolar tissue lies under the serous coat and sends the extensions in between the lobules. It is full of lobules large and small. The larger lobules are at the periphery and the smaller ones centrally. Each of it, is made of a terminal bronchiole and its air cells; vessels, nerves and lymphatics. Larger branches of the bronchi present outer fibrous coat containing mucous glands and irregularly arranged plates of hyaline cartilage. Lying inside it, is the circularly arranged smooth muscle fibres and are known as bronchial muscles. Mucous membrane forms of inner layer and has the well defined basement membrane, with ciliated columnar epithelial cells. The mucus membrane contains lymphoid tissue and the ducts of the mucous glands. Terminal bronchioles are followed by respiratory bronchioles which are followed by alveolar ducts, atria and the alveoli. They do not have hyaline cartilages in their walls and the mucous membrane is lined with cubical, non-ciliated epithelial cells. Alveolar ducts, atria and the air succules are lined by the simple squamous epithelium. Alveolar duct has little amount of muscle fibres. These muscle fibres are more in number at the entrance of the duct into the atria. No muscle and the fibrous tissue, are present in the walls of the atria and the succules. However, it has a small amount of elastic fibres. Lung alveoli are in contact with the pulmonary capillary plexuses. As regards the elements, separating the alveolar air from the blood, in the capillaries two views were expressed. 1. Only the capillary endothelium intervenes, the alveolar epithelium being deficient in many parts. 2. Electron microscopy and the histochemical study showed presence, both the layers. Alveoli has the special type of cells which show amoeboid character. They take the dust particles and other waste and carry it to the bronchioles. The material is brought out by the ciliary action of the cilia of the cells and the process of coughing. Respiratory bronchiole, its duct, atria and the air succules from the pulmonary unit.

Trachea Note:

Blood Vessels:

Nerve Supply of Lungs:

Microscopic Anatomy of Trachea and Lung:

Note:

Intrapulmonary Bronchus: Terminal Bronchiole: Respiratory Bronchiole:

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During inspiration bronchial muscles get relaxed and contract during expiration. Respiratory part in the foetal lung, is lined with the cubical epithelium, which gets flattened after the act of first respiration. 1. Pulmonary arteries: Pulmonary arteries bring deoxygenated blood and form the intricate plexus around the alveolar walls. 2. Pulmonary veins (Two veins for each lung): They arise from the pulmonary capillaries and do not accompany the pulmonary arteries and their bronchi. They open into the left atrium. 3. Bronchial arteries (see Figure 85): They arise from the descending thoracic aorta, and the right third posterior intercostals artery. There is one on the right and the two are on the left. They supply the portion of the lung tissue only up to the respiratory bronchiole. Right bronchial artery is the branch of the right third posterior intercostals artery or may arise from upper left bronchial artery. On the left side there are two bronchial arteries upper and the lower. Both of them arise from descending thoracic aorta. There are pre-capillary connections between the bronchial and the pulmonary arteries. Pulmonary arteries bring de-oxygenated blood to the lungs while the pulmonary veins carry oxygenated blood to the left atrium. Lungs are supplied by parasympathetic and sympathetic nerves. Parasympathetic nerves are the branches of the vagus. They are motor and can cause bronchospasm. Secretomotor fibres supply a mucus glands. Stretch reflex of the lung is due to sensory fibres which causes cough (Reflex). Sympathetic supply of the lung comes from the 2 to 5 spinal segments. They act as inhibitory to the smooth muscle as well as the glands of the bronchi. In asthma sympathomimetic durgs are used to relieve bronchospasm. Sympathetic and the parasympathetic nerves form an anterior and the posterior pulmonary plexuses. The trachea is made of “C” shaped hyaline cartilaginous rings which are open posteriorly. The posterior gap is filled by fibrous tissue. It contains muscle known as trachealis. The trachealis muscles can change the size of the lumen of the trachea. The “C” shaped cartilages are supported by fibro-muscular tissue. Mucus membrane of the trachea is lined by the pseudo-stratified ciliated columnar epithelium having goblet cells. Lamina propria has connective tissue and the ducts of the gland occupying the sub-mucosa. Muscularies mucosae is absent. Submucus coat contain serous and mucus ascini. Posterior wall of the trachea is made of the stretchable fibro-muscular tissue with two objects (i) which can change the diameter of trachea, (ii) and allows bulging of the oesophagus anteriorly during passage of a large bolus of food. Epithelium and the lamina propria are same as that of the trachea. Outer covering consists of small pieces of cartilages and glands. Outermost covering is formed by the connective tissue. The lining of the terminal bronchiole is by the non-ciliated columnar epithelium without goblet cells. Cartilages and the glands are totally absent. Respiratory bronchiole is lined by cuboidal cells. They are surrounded by smooth muscle fibers and the connective tissue. There are no glands or cartilages in the respiratory bronchiole. Alveoli are lined by squamous epithelium. There are few cuboidal cells in the alveoli which produce

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Segmental Representation of the Right and Left Lungs: Right Lung (Figures 78 and 79):

Lower Lobe:

Left Lung:

Lymphatic Drainage of Lungs (Figure 103): Superficial: Deep:

Roots of the Lungs (Figures 98 and 99):

surfactant. Surfactant is produced by the cuboidal cells between the 32 to 34 weeks of the intra-uterine life. Segmental representation of the right and left lungs from the anterior aspect.

Upper lobe of the right lung is divided by upright Y shaped line of demarcation into apical, anterior and posterior. Medial and lateral lobes of the middle are divided by a vertical line, which separates middle lobe. It is marked by an oblique fissure showing triangular apical and anterior basal, lateral basal and posterior basal by two lines from medial to lateral side. Upper lobe of left lung shows apical posterior and anterior lobes above. The oblique line it presents superior, lingular and inferior lingular lobes. Below the oblique line upper most triangular area is occupied by apical lobe. (Apical basal) and the rest of the area is marked by two vertical lines dividing this surface into three lobes. Anterior, lateral and posterior basal from medial to lateral side. It is divided into the superficial and the deep groups.

Peripheral part of the lung under the pulmonary pleura is drained by the superficial group of lymphatics which go towards the hilum. Deep group drains bronchial tree, pulmonary vessels, areolar and connective tissue with septae. They drain into broncho-pulmonary nodes. The division of lymphatic drainage into the superficial and the deep is artificial as both the systems are connected with each other. Superficial lymphatic vessels present number of valves while the deep lymphatic vessels have very few or none. Roots form the connection between the mediastinum and the lungs. They lie at the level of bodies of the 5 to 7 thoracic vertebrae. Each root of the lung is surrounded by a fold of pleura, which hangs down from the root of the lung to the diaphragm below (Pulmonary ligament). Name

Root of the right lung

Root of the left lung

1. Bronchus

Eparterial and hyparterial Only one bronchus bronchus

2. Pulmonary artery

It is infront of the bronchi

Pulmonary artery is above the bronchus

3. Pulmonary veins

Two in number below and infront

Two in number below and infront

4. Bronchial artery

One bronchial artery

Two bronchial arteries.

5. Pulmonary plexus

Anterior, posterior

Anterior, posterior

6. Bronchial node

Present

Present

7. Lymphatics

Present

Present

8. Areolar tissue

Loose areolar tissue which allows dilatation of pulmonary veins

Loose areolar tissue which allows dilatation of pulmonary veins

9. Pulmonary ligament

Present

Present

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Figure 98 Showing root of right lung

Figure 99 Showing root of left lung

Summary:

Relations of the Root of the Right Lung:

Root of the left lung differs from the root of the right in the following respects. 1. One bronchus 2. Pulmonary artery above 3. Two bronchial arteries The rest is same on both the sides. Anterior: 1. Phrenic nerve 2. Pericardiophrenic artery. 3. Anterior pulmonary plexus 4. Superior vena cava 5. Right atrium Posterior : 1. Right vagus nerve 2. Posterior pulmonary plexus Superior : 1. Azygos vein 2. Trachea 3. Right vagus

Relations of the Root of the Left Lung:

Inferior : 1. Pulmonary ligament Anterior: 1. Left phrenic 2. Pericardiophrenic artery 3. Left ventricle 4. Pulmonary trunk. Posterior: 1. Descending thoracic aorta. Superior: 1. Arch of aorta with two branches, namely the left common and the left subclavian arteries.

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Auscultation of Lungs: Surface Markings of the Fissures of the Lung (Figure 100): Oblique Fissure (Figure 101): Transverse Fissures: Relations of Apex of Lungs (Figure 102):

Figure 100 Showing right lung with oblique and horizontal fissure with three lobes

Figure 101 Showing left lung with oblique fissure two lobes and cardiac notch

Inferior: 1. Pulmonary ligament. 2. Oesophagus Auscultation of the lung is done with the help of a stethoscope. Clinically upper part of the lung is auscultated from the front and the lower part from the back while axilla is the site of the auscultation for the rest of the lung. Right lung has an oblique and transverse fissures dividing the lung into three lobes the superior, middle and the inferior. Left lung has an oblique fissure only, which divides the lung into superior and inferior lobes. Left lung has no transverse fissure. It runs downwards and forwards from a point 2 cm lateral to the spine of the third thoracic vertebra. It cuts the fifth rib in the mid-axillary line and ends at sixth costochondral junction. It runs along the right fourth rib and meets the oblique fissure in the mid-axillary line. They are important as structures related to the apex of the lung are involved in the carcinoma of the apex. The apex is covered with cervical pleura and Sibson’s fascia. It is most superficial and can get injured due to the stab or a bullet. Anteriorly apex of the lung is crossed by subclavian artery and the subclavian vein separated by the scalenus anterior muscle. The artery is behind the muscle at a higher level than the subclavian vein. Scalenus anterior muscle is inserted into the scalene tubercle on the medial border of the first rib.

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Figure 102 Showing branches of 2nd part of subclavian artery

Figure 103 Showing lymphatic drainage of the lungs

i. Posterior relations: They are the ascending branch of the ventral ramus of the first thoracic nerve, superior intercostals artery and the sympathetic chain from lateral to medial. All the three structures are placed in front of the neck of the first rib (It can remembered as NAC instead Neck) from lateral to medial side. (N-Nerve, A-Artery, C-Chain). ii. Lateral relations: Lower trunk of the brachial plexus and the scalenus medius muscle. iii. Medial relations of the apex of the right lung: On the right side the structures are placed anteroposteriorly as under: a. Right brachiocephalic vein b. Right phrenic nerve, c. Brachiocephalic artery, d. Right vagus, e. Trachea. iv. Medial relations of the apex of the left lung (Figure 96): a. Left brachiocephalic vein, b. Left subclavian artery, c. Left recurrent laryngeal nerve, d. Esophagus, e. Thoracic duct. Note: One important structure on the left is the thoracic duct. It can be said that the thoracic duct spoils the symmetry of the front of the root of the neck.

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Cancer of the Apex of the Lung:

Clinical evidence of the spread of the cancer is detected by the symptoms and signs which are according to the structures involved. 1. Lung: Patient develops dyspnoea due to involvement of the lung tissue. 2. Large pleural effusion due to involvement of the pleura in cancer, the pleural cavity presents bloods stained fluid. 3. Clubbing of the finger. (The finger at the base of the nail develops thickening.) It is due to chronic anoxia. 4. Persistent cough, haemoptysis (coughing of blood), loss of weight with severe local pain in the chest are due to the involvement of the chest wall. Radiating pain along the upper limb is due to the involvement of the lower trunk of brachial plexus affecting the ulnar nerve. 5. Recurrent laryngeal nerve, hoarseness of voice. 6. Compression of brachiocephalic vein and the superior vena cava causes oedema of the upper limb and the neck. 7. Subclavian artery: Compression of the subclavian artery reduces the force of the radial pulse and cause vascular symptoms. 8. Phrenic nerve: Hemi-diaphragm 9. Sympathetic chain: Horner’s syndrome. 10. Hormonal effect: Carcinoma of the lung produces a harmone or the chemical substance which causes weakness of the muscles, it is known as myopathy. 11. Eaton-Lambert syndrome: It is similar to the condition known as myasthenia gravis, which is seen in the tumors of the thymus. 12. Pancoast’s syndrome: The signs and symptoms of this syndrome are due to involvement of the structures related to the posterior aspect of the apex of the lung. 1. Pain along the ulnar nerve and wasting of the small muscles of the hand. 2. Erosion of the first rib seen in X-ray. 3. Horner’s syndrome 4. Radiopaque shadow at the apex of the lung. 1. Barrel chest: In chronic asthma, lungs get distended and the thoracic cage gets permanently enlarged. 2. Pulmonary fibrosis: The loss of elasticity of the lung tissue due to pulmonary fibrosis causes incomplete expiration. In cancer of the lung and asbestosis distensability is lost. 3. Lung abscess: Lung abscess usually follows the upper respiratory tract infections such as sinusitis and dental abscess. Obstruction of the bronchus due to carcinoma can cause lung abscess following collapse of the lung. Infection causes thrombosis of the artery and the vein of the segment causing necrosis followed by an abscess. 4. Bronchiectasis: It is the chronic and almost permanent dilatation of the medium size bronchi due to weakness of their wall. 5. Postural drainage for the lung abscess: It is based on the distribution, direction of the bronchi. Position of the patient and the gravity plays an important role in postural drainage for which the knowledge of the broncho-pulmonary segment is must. 6. Hyaline membrane disease: Hyaline membrane lies between the pulmonary alveoli and the capillaries disappears at birth and the gaseous exchange begins. Hyaline membrane may persists

Trachea

Clinical:

Development of Lungs:

Anomalies of the Trachea and the Lung:

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preventing the gaseous exchange. The term hyaline membrane disease is obsolete these days. It is known that absence of the surfactant is the cause. Surfactant is produced by the pneumocyte type-II. 7. Thoracic cage in the old: 1. Rigid thorax : Elasticity and pliability of the thorax is reduced due to the calcification of the costal cartilages. 2. Kyphosis: Curving forward of the spine due to the dessication of nucleus pulposus of the intervertebral disc which acts as the ball-bearing of the vertebral column. 3. Atrophy of muscles: Old age atrophy of thoracic and abdominal muscles. 4. Degeneration of elastic tissue: Elastic tissues of the lungs get degenerated. Due to reduced respiratory capacity old persons suffer from respiratory infections. They are prone to develop post-operative hypostatic pneumonia. For reducing the risk intensive physiotherapy of the chest is very essential. The lung is endodermal in origin and develops in the form of trachiobronchial diverticulum from the ventral aspect of the foregut. It divides into two forming the lung buds. Lung buds invaginate the primitive pleural cavity and get covered by the visceral layer of the pleura. Visceral pleura is developed from splanchnic mesoderm and is not sensitive to pain. Parietal pleura is sensitive to the pain as it develops from the somatic mesoderm. Muscles, cartilages and connective tissues are formed by the mesoderm. The tracheal diverticulum further bifurcates to form the right and the left bronchi. Right bronchus is almost vertical in line with the trachea while the left bronchus is transversely placed. Right bronchus gets divided into three while the left into two. 1. Tracheo-oesophageal fistula – occurs as the result of failure of separation of two tubes. 2. Accessory bronchus 3. Tracheal bronchus 4. Accessory lobe 5. Azygos lobe – Azygos vein cuts apex of the right lung down to the root. Part of the lung tissue medial to vein is known as azygos lobe. 6. Agenesis – is the non-development of the lung. 7. Pericardial cavity communicates with the pleural cavity and the pleural cavity communicates with peritoneal cavity as an anomaly of the intra-embryonic coelom. Please remember that the pericardial, pleural and the peritoneal cavities develop from the intra-embryonic coelom. 8. Sequestration of lung: It is the part of the lung which is separately supplied by the branch from the aorta and has drainage into the systemic circulation. It is independent from lung. It can be inter or extralobar. Extralobar lies below the diaphragm. Aortography shows the abnormal artery which is identified and ligated at the pulmonary ligament. (Root of the lung).

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PERICARDIUM The pericardium is the sac for the heart and roots of great vessels. It lies behind the sternum opposite the second to the sixth costal cartilages. (Corresponding to the fifth to the eighth thoracic vertebrae). However in the recumbent position it lies opposite the sixth to ninth thoracic vertebrae. It presents two distinct parts, the fibrous and the serous. Out of these, fibrous pericardium is the single layered sac containing heart and roots of the great blood vessels. It appears as if the great blood vessels are coming out from the mouth of a single layered fibrous bag. It must be remembered that the pre-tracheal layer of the cervical fascia gets fused with the adventatia of the great blood vessels, i.e. aorta and the pulmonary trunk. The closed serous sac is invaginated by the heart from the posterosuperior aspect. Due to this invagination the original cavity is obliterated leaving the potential space, which is known as the pericardial cavity. It contains 50 ml of fluid which is like the lymph. It is only after the invagination by the heart, the serous pericardium presents two layers, the visceral and the parietal.

Fixation of the Pericardium in the Mediastinum (Figure 104):

Functions of the pericardium: 1. Protection of the heart. 2. To minimize the friction. 3. To prevent the excessive fall of diastolic pressure. 4. Prevents infection. Note: Large defects of the pericardium produced congenitally or surgically have not shown any ill-effect. By virtue of the following ligaments the fibrous pericardium is fixed in the mediastinum.

Figure 104 Sagittal section of middle mediastinum showing sternopericardial ligaments

1. Sternopericardial ligaments: They are two in number, superior and inferior. They attach the fibrous pericardium to the posterior surface of the sternum. 2. Phrenico-pericardial ligaments: The base of the fibrous pericardium is fused with the central tendon of the diaphragm. Elsewhere the fusion between the pericardium with the diaphragm is by means of the loose fibrous tissue.

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Figure 105 Showing fibrous pericardium and the structures inside

Fibrous Pericardium (Figure 105):

Serous Pericardium (Figures 106 and 107):

Clinical Importance of the Transverse Sinus: Figure 106 Showing arrangement of fibrous and serous pericardium

As already described it is a single layered bag containing heart and the great blood vessels. It is cone shaped having base directed towards the diaphragm and apex upwards. At the apex it is fused with the fibrous coat of the vessels and the pretracheal fascia of the neck. Fibrous pericardium provides covering to the pulmonary artery, root of the aorta, four pulmonary veins, superior vena cava excluding the inferior vena cava as it pierces the central tendon of diaphragm and immediately enters the right atrium. The parietal layer of the serous pericardium lines the inner surface of the fibrous pericardium while the visceral layer covers the anterior and posterior surfaces of the heart. At the point of reflections both the layers are continuous with each other. The serous pericardium is arranged in two tubes, one for the aorta and pulmonary trunk while the other for the superior, inferior vena cavae, and the four pulmonary veins. Because of the arrangement of the serous pericardium, two sinuses are formed, i.e. (i) transverse and the (ii) oblique sinuses. Transverse sinus is limited by the aorta and the pulmonary trunk in front and upper margin of the left atrium behind. Appearance of the transverse sinus dates back to the time of embryonic development. During early stages of development the single endocardial tube is attached to the dorsal wall of the pericardium by the double fold of mesocardium. With the disappearance of dorsal mesocardium the transverse sinus appears. During operation for the pulmonary embotectomy, it can be used for keeping the rubber catheter or the finger as support to the pulmonary trunk.

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Figure 107 Dorsal mesocardium disappears and transverse sinus appears

Oblique Sinus of the Pericardium (Figures 108 and 109):

Oblique sinus is posterior to the left atrium and lies between the visceral and parietal layers of the serous pericardium. It allows the dilation of left atrium.

Figure 108 Showing transverse and oblique sinuses of pericardium viewed from behind

Figure 109 Showing transverse sinus of pericardium

The Attachment of the Second Tube: Ligament of the Left Vena Cava: Blood Supply of the Pericardium:

The attachment of the second tube enclosing the superior, inferior vena cavae and the four pulmonary veins, forms the cul-de-sac, which is open to the left and below. Ligament of the left vena cava is the triangular fold of a serous pericardium which stands out as the fold over the remnant of the left duct of Cuvier. 1. Internal thoracic mammary arteries 2. Pericardio-phrenic arteries 3. Inferior phrenic arteries 4. Bronchial arteries 5. Esophageal arteries.

Pericardium

Venous Drainage: Nerve Supply: Congenital Anomalies:

Clinical:

Figure 110 Showing paracentesis of pericardial effusion

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The internal thoracic mammary and the inferior phrenic arteries freely anastomose forming an important potential collateral channel between first part of the subclavian artery and the abdominal aorta. Veins drain into the azygos, hemi-azygos, internal mammary and the inferior phrenic veins. It is supplied by the vagus, phrenic and the sympathetic nerves. 1. Congential absence: It is rare 2. Congenital large defects: They are more common on the left side due to the early disappearance of the left duct of Cuvier. The complications of such defects are rare. Inflammation of the pericardium is known as pericartitis. The pericardial rub due to friction of the pericardial layers is diagnostic. It is high pitch sound produced by the friction of the inflammed layers of the pericardium. 1. Constrictive pericarditis: Constrictive pericarditis is mostly due to tuberculous infection where the pericardium gets thickened and calcified. For relief only the part of the pericardium limited to the left ventricle is excised. Pericardium over the atria is not touched due to the likelihood of opening the thin-walled atria and the great veins. Appreciable relief cannot be expected unless the borders of the heart, the superior and the inferior vena cavae are freed from the thickened pericardium. 2. Exposure of the heart: a. By removal of the three to six costal cartilages alongwith resection of the part of the sternum and the ribs. b. Sternum splitting incision is commonly used with utmost care to protect the left brachio-cephalic vein, which is directly related, to the upper half of the manubrium sterni. 3. Pericardial effusion (Figure 110): Pericardial effusion is an excessive accumulation of fluid, in the pericardial cavity leading to cardiac tamponade, which interferes with cardiac filling. The term is used for describing acute failure of the heart due to compression of the heart by the excessive or rapidly increasing pericardial fluid. Removal of fluid with the needle is known as paracentesis. The most important complication is the entry of needle into the anterior descending branch of the left coronary artery. In case of large effusion the danger is minimized. Left costo-mediastinal recess of the pleural sac is shifted

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Kadasne’s Textbook of Anatomy (Clinically Oriented) to the left, allowing the pericardium to lie in direct contact with the sternum, reducing the possibility of entering the pleural cavity. Clinical: Haemorrhagic pericardial effusion is mostly due to the malignancy if not due to trauma. 4. Method of aspiration: Short bevelled needle is passed along the xiphoid process directed backwards and upwards with an angle of 45° to the skin toward the left shoulder. 5. Development of pericardium: Fibrous pericardium and the parietal layer of serous pericardium develop from somato-pleuric and the visceral layer develops from the splanchno-pleuric mesoderm. The closed cavity of the serous pericardium is invaginated by the heart.

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HEART The heart is the fibro-muscular hollow organ situated in the mediastinum obliquely under the sternum. Its base is directed posteriorly and the apex anteriorly to the left. It is not a mid-line structure as its right one third lies to right of the mid-line. It is of the size of a fist and it weighs about 300 grams. It has four chambers and four openings. Chambers: Two atria: right and the left. Two ventricles : right and the left.

Apex:

Borders of the Heart:

Sternocostal Surface of the Heart (Figures 111 to 113 and 116):

Openings : They are four in number 1. Right atrio-ventricular opening 2. Left atrio-ventricular opening 3. Pulmonary opening 4. Aortic opening. Note: All the openings are placed in the fibrous base of the heart which maintains their patency in the muscular organ. Note: Left posterior atrio-ventricular groove is occupied by the circumflex branch of the left coronary artery and the coronary sinus carrying blood from left to the right. Circumflex branch of the left coronary artery carries an arterial blood while the coronary sinus carries venous blood in the same direction, e.g. from left to the right. Probably it is the only example in the body where arterial and the venous blood flow in the same direction. Apex of the heart lies in the left fifth intercostals space 9 cm from the sternal margin or in the left fifth intercostals space little medial to the mid-axillary line. It must be remembered that the apex of the heart is formed by left ventricle and its blood supply comes from the left coronary artery. The heart has four borders, i.e. superior, inferior, right and the left. 1. Superior border of the heart : The superior border is formed by the superior borders of the left atrium and partly of the right. 2. The right border of the heart is formed by the right atrium. 3. The left border is formed by the left ventricle. 4. The inferior border of the heart is mainly formed by the right ventricle. Sternocostal surface lies in contact with sternum and the costal cartilages. It is the larger surface. If studied carefully it gives complete idea about the orientation of the chambers of the heart and positions of the coronary arteries. The sternocostal surface presents two grooves namely the right atrio-ventricular and the anterior inter-ventricular. The right atrioventricular runs from the right of the pulmonary trunk to the point of junction of the right and the inferior borders of the heart. Inter-ventricular groove is seen running from the upper end of the heart towards the apex. It is the line of demarcation between the right and the left ventricles. More than two-thirds of the sternocostal surface is formed by the right ventricle and one third by the left. Upper part of the right ventricle presents the dialation which is known as the infundibulum. Infundibulum continues

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Figure 111 Sternocostal surface of heart showing grooves

Figure 112 Showing sternocostal surface of heart

Figure 113 Sternocostal surface of heart showing grooves

superiorly to form the pulmonary trunk. Pulmonary trunk divides into right and the left pulmonary arteries under the arch of aorta. To the right of the pulmonary trunk, are the ascending aorta and the superior vena cava. The ascending aorta is to the right pulmonary trunk while the superior vena cava lies on the right of the ascending aorta. The right atrioventricular groove, demarcates the limit of the right atrium and the right ventricle. It is known as anterior part of the right atrio-ventricular groove. It runs from the root of the pulmonary trunk to the apex of the heart. Pulmonary trunk is overlapped on either side by the auricles of the right and the left atria (As ears on either side of the snout of a dog). The relation of the pulmonary trunk to the aorta is important. In the proximal part pulmonary trunk lies in front of the ascending aorta. As it goes up and to the left. It lies medial to the ascending aorta. Finally it lies under the arch of the aorta and divides into the right and the left pulmonary arteries. In brief sternocostal surface of the heart presents right atrium, right ventricle, left ventricle, left atrium (left auricle), infundibulum and the pulmonary trunk.

Heart

Base of the Heart (Posterior Surface) (Figure 115):

Posterior Relations of the Left Atrium (Figure 114):

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Both the coronary arteries make their first appearance on the sternocostal surface of the heart on either side of the pulmonary trunk and are overlapped by the right and the left auricles. The posterior surface of the heart can be seen from the posterior aspect. It is formed by the right and the left atria, where the major portion is formed by the left atrium. Lower down it presents coronary sinus, while its upper border reaches the division of the pulmonary trunk. Four pulmonary veins enter the left atrium through this surface. It must be remembered that the oblique sinus of the pericardium forms an important relation of the posterior surface of the left atrium along with the descend, thoracic aorta and the oesophagus. The oblique sinus of pericardium, descending thoracic aorta and the oesophagus form the posterior relations. In mitral-stenosis left atrium gets enlarged and presses on the oesophagus leading to the dysphagia. Radiologically it can be confirmed in left lateral view of the thorax in the barium swallow of the oesophagus.

Figure 114 Posterior relations of left atrium

Figure 115 Showing posteroinferior view of the heart

Diaphragmatic Surface of the heart: Right Atrium (Figure 117):

The diaphragmatic surface lies on the central tendon of the diaphragm. It is formed by the right and the left ventricular portions which are separated by the posterior interventricular groove. A small part of the right atrium takes part in the formation of the diaphragmatic surface. The right atrium forms the right border of the heart, which is continuous above with the superior vena cava and below with the inferior. External surface of the right atrium presents the groove which runs from the superior vena cava to the inferior. It is known as sulcus terminalis. It creates the ridge inside the right atrium known as the crista terminalis. To the left of the sulcus terminalis lies the ear like projection of the right atrium known as the auricle. It has already been stated that the right coronary artery appears on the sternocostal surface between the pulmonary trunk on the left and the right auricle on the right.

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Figure 116 Showing anterior view of the heart and important blood vessels including coronaries

Figure117 Interior of the right atrium viewed after opening (right lateral wall)

Interior of the Right Atrium (Figure 118):

Figure 118 Showing interior of the right atrium

Antero-lateral surface of the right atrium is related to 1. Phrenic nerve, 2. Pericardiaco-phrenic artery. 3. Pleura 4. Pleural cavity 5. Pulmone (lung) Aid to memory: Antero-lateral relations of the right atrium are presented by five ‘P’s. Interior of the right atrium shows two parts, the anterior and the posterior. They are separated by the ridge running from the opening of superior vena cava to the opening of the inferior. It is known as crista terminalis which is marked by the sulcus terminalis on the exterior of the right atrium. Niusculi pectinati arise from the crista terminalis like the teeth of a comb.

Heart

Right Ventricle (Figures 119 to 121):

Moderator Band (Figures 119 and 121):

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This part forms the rough portion of the right atrium. Posterior to the cresta terminalis is the smooth part. It receives openings of superior vena cava in the upper and the posterior part and the inferior vena cava in the lower posterior part. Immediately to the left of the opening of the inferior vena cava is an opening of the coronary sinus. Opening for the superior vena cava is without valve, while the openings of the inferior vena cava and the coronary sinus are with valves. Triangle of Koch lies between the base of the septal leaf, antero-medial margin of the coronary orifice and tendon of Todaro which runs between the right fibrous trigone to the medial end of the valve of the inferior vena cava. Triangle of Koch’s is an important land-mark for cardio-vascular surgeons as the AV node lies here. Blood from the right atrium passes through the right atrio-ventricular orifice and enters the right ventricle. The right atrio-ventricular opening is pointed forwards and medially and gets closed during contraction of the ventricle. This opening is known as tricuspid opening, as it has three cusps. The portion of the right atrium which lies behind the cresta terminalis develops from the right horn of the sinus venosus. Area infront of the cresta terminalis develops from the primitive atrium proper. In short right atrium is formed by: 1. Primitive right atrium, 2. Sinus venosus and 3. Right atrio-ventricular canal. To the left of the opening of the coronary sinus is the right atrioventricular opening. Interior of the right atrium presents inter-atrial septum, which lies anterior to the left atrium. On the right side of the inter-atrial septum, fossa ovalis and the annulus ovalis are seen. The floor of the fossa ovalis is formed by the septum primum and the annulus ovalis is formed by the septum secondum. During development, sinus venosus shifts to the right and opens in the right atrium by the wide opening known as an opening of the sinus venosus. It has two valves right and the left. Right valve of the opening of the sinus venosus forms the following structures. 1. Crista terminalis 2. Valve of the inferior vena cava 3. Valve of the coronary sinus. The interior of the right ventricle is grossly divided into the inflow and the outflow tracts. These tracts are placed at right angle to each other. Inflow tract is rough as it presents muscular ridges of three types. Elevations, bridges and the papillary muscles which are also known as pillars. There are three papillary muscles. They are attached to the cusps of the right atrio-ventricular opening by means of chordae tendineae. Two tracts are separated superiorly by the muscular ridge, known as the supraventricular crest. It is situated between the tricuspid and the pulmonary valves. Near the apex there is the thick muscular band covered with endocardium. It runs from the inter-ventricular septum medially to the base of the anterior papillary muscle laterally. It is known as the moderator band. Inflow tract of the right ventricle develops from bulbus cordis. Smooth part is also known as infundibulum and it continues as the pulmonary trunk. The moderator band is the thick muscular band covered with endocardium placed in the right ventricle near the apex, running from inter-ventricular septum to the base of the anterior papillary muscle.

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Figure 119 Showing interior of right ventricle

Figure 120 Schematic drawing of right ventrical showing inflow and outflow tracks

Figure 121 Showing right and left ventricular cavities with papillary muscle

Functions of Moderator band:

The chordae tendineae are attached to the margins and the ventricular surfaces of the two adjoining cusps. Chordae tendineae prevent the cusps from projecting into the right atrium. 1. Prevents over distention of the right ventricle during filling phase, as it resists the separation of the anterior and the septal walls of the right ventricle. 2. Acts as the pathway for right branch of atrioventricular bundle. (Bundle of His). Openings of the right ventricle : Right ventrical has two openings 1. Right atrioof ventricular and 2. Pulmonary.

Heart Right Atrioventricular Opening (Tricuspid valve) (Figure 121):

Pulmonary Opening (Figure 120):

Pulmonary Valve (Figure 122):

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Right atrio-ventricular opening is situated in the lower and posterior part of right ventricle at the fourth intercostals space and is surrounded by the fibrous ring. It has three cusps, anterior, medial and the septal, attached to the fibrous ring. Out of these the anterior cusp intervenes between the tricuspid orifice and infundibulum while medial and inferior are respectively related to the septal and inferior walls of the ventricle. Chordae tendineae as already stated, gain attachement to apex, margin and the ventricular surfaces of the cusps. The atrial surface of valves remain smooth being devoid of the attachments of the chordae tendineae. First sound of the heart is due to the closure of the atrioventricular valves and the second sound is due to closure of semilunar valves. The out flow track of the right ventricle constitutes the infundibulum which continues as the pulmonary trunk. Walls of the infundibulum are smooth. Embryologically the infundibulum develops from the bulbus cordis. Inside the right ventricle the walls are filled with irregular small muscles known as trabeculae carneae. There are three papillary muscles in the right ventricle, namely the anterior, posterior and the septal. Papillary muscles are attached to the margins of the cusps through the chordae tendineae. The pulmonary valve consists of three cusps semilunar in shape. Their bases are attached to the fibrous ring surrounding the opening which maintains the patency of the opening. Arterial surface of it is concave while the ventricular surface is convex. Structurally it consists of fibrous tissue covered on either side by an endothelial layer. Free margin of the cusp presents nodule of the valve and on either side of it lie the lunules of the valve. After the ventricular contraction cusps come in opposition. Thus pulmonary valve plays an important part in preventing regurgitation of the blood into the ventricle. Arterial aspect of the semilunar pulmonary cusps present depressions known as the pulmonary sinuses. After ventricular contraction there is return of the blood which fills the pulmonary sinuses forcing the cusps to close.

Figure 122 Showing cusps of pulmonary and aortic openings

Pulmonary Trunk (Figure 123):

Pulmonary trunk begins from the upper end of the infundibulum under the sternal end of the third left costal cartilage and ascends upwards, backwards and slightly to the left to reach under the concavity of the arch of aorta where it divides into the right and left pulmonary arteries. The fibrous pericardium merges with the outer fibrous coat of the root of the pulmonary trunk. It is enclosed alongwith the ascending aorta in the tube of the serous pericardium. The transverse sinus of the pericardium is bounded by the ascending aorta and the pulmonary trunk, anteriorly. The superior margin of the left atrium forms posterior boundary of the transverse sinus of the pericardium.

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Figure 123 Horizontal section at the fifth thoracic vertebra (seen from above)

Length and Diameter of the Pulmonary Trunk: Relations:

Right Pulmonary Artery:

Left Pulmonary Artery: Ligamentum Arteriosum:

Left Ventricle (Figures 124 and 125):

Diameter of the pulmonary trunk is exactly half of its length (Length5 cm; Diameter-2.5 cm). In the lower part, it lies in front of the ascending aorta and is directed backwards, upwards and to the left and comes to lie on the left side of the ascending aorta. Apex of the right auricle and right coronary artery on the right while the left coronary artery and auricle of the left atrium on the left of the root of the pulmonary trunk. The right pulmonary artery runs downwards and to the right to enter the hilum of the right lung. During this course it is related to the left atrium and transverse sinus of the pericardium. Superior vena cava and ascending aorta are anterior while right bronchus and the oesophagus are posterior to the right pulmonary artery. Left pulmonary artery lies in front of the descending thoracic aorta and the left bronchus. The important posterior relation of left pulmonary artery is left atrium. It is the fibrous remnant of the ductus arteriosus which is the important connecting link between pulmonary trunk and the arch of aorta during embryonic life. This link is kept patent by virtue of the fact that the pressure in pulmonary trunk is always greater than the pressure in the aorta. In adult life left recurrent laryngeal nerve hooks the ligamentum arteriosum from the left. Superificial cardiac plexus is to the right of the ligamentum arteriosum. Left ventricle has inflow and the outflow tracts. Outflow tract continues as aortic vestibule and further as the ascending aorta. These two tracts are placed at an acute angle. Walls of the left ventricle are three times thicker than that of the right due to its function, of pumping blood to the all the parts of the body. The appearance in cross section of the heart looks circular or oval as the interventricular septum is pushed to right due to more pressure in the left ventricle. Its walls present trabeculae carnae and two papillary muscles, the anterior and the posterior of which anterior papillary muscle is attached to the anterior and the posterior papillary muscle is attached to the posterior walls. Chordae tendineae from the anterior papillary muscle go to the anterior cusp and from the posterior go to the posterior cusp of the mitral valve. Left ventricle is overlapped by the cavity of the right ventricle anteriorly, laterally, and posteriorly.

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Figure 124 Showing sagittal section through left auricle and left ventricle

Figure 125 Shows how the right ventricle overlaps the left ventricle

Figure 126 Showing tricuspid valve

Left Atrio-ventricular Orifice (Mitral or Bicuspid Orifice) (Figure 127): Figure 127 Showing mitral (Bicuspid) valve

The opening is situated in the lower and posterior part of the left ventricle, lying behind the left half of the sternum at the level of the fourth costal cartilage. It has two cusps anterior and the posterior. They are attached to the fibrous ring at the periphery and are fused partially

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Kadasne’s Textbook of Anatomy (Clinically Oriented) with adjoining cusps. Mitral opening admits only two fingers and has the diameter of 5 cm during diastole.

CLINICAL Mitral Stenosis:

Left Atrium:

Atrial Myxomas:

Aortic Orifice (Figures 128, 129 and 140):

Figure 128 Showing aortic valve

Figure 129 Showing interventricular septum separating the ventricles

Mitral stenosis is the narrowing of the left atrio-ventricular orifice, and is mostly rhematic in origin. The mitral opening gets reduced to 1 cm from 5 cm. Clot retension in the left atrium is a serious complication due to chances of embolisum. As the left atrium lies infront of the oesophagus, its dilatation leads to oesophageal compression causing dysphagia. Mitral stenosis can be treated by dilatatation of the openings by a ballon (valvulo-plasty). The mitral valve can be replaced with the synthetic one. The anterior or the right wall of the left atrium is formed by the interatrial septum. The left atrio-ventricular opening is situated in front and to the left. The walls are smooth except for the small part of the auricle. Four pulmonary veins open into it, from the posterior side piercing the fibrous pericardium. In side the fibrous pericardium the veins are covered by the serous pericardium. These openings do not have valves. The posterior relations of the left atrium, i.e. oesophagus and the descending thoracic aorta should never be forgotten. They are the multiple, gelatinous or solid pedunculated tomours attached to the inter-atrial septum. They are common in left atrium and can be surgically removed. The situation of the aortic opening is in the upper and posterior part of the left ventricle. Ventricular portion proximal to the aortic orifice is thin walled. It is made of fibrous and elastic tissues. It is described as aortic vestibule. Aortic orifice lies behind the sternum at the level of the lower border of the third left costal cartilage. It has three cusps one anterior and the two posterior. Nearer the cusps, aortic wall presents three dilatations known as the aortic sinuses. Right coronary artery arises from the anterior aortic sinus and the left coronary arises from the left posterior aortic sinus. The arrangement of the origin of the coronaries, is constant, however abnormal pattern is not uncommon.

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Note: We have seen four openings in the heart, having valves. Surface marking of these valves can be memorised if you remember 3, 3.5, 4, 4.5, meaning is simple 3 for rib 0.5 for space 4 for rib and 0.5 for space. Please Ask Mr. Thorax. PAMT

Interventricular Septum:

Structure of the Heart (Figure 130):

Figure 130 Showing fibrous base of heart

P – Pulmonary

A- Aortic

M-Mitral

T-Tricuspid

3rd rib

3½ space

4th rib

4½ space

Interventricular septum separates the right and the left ventricles. It has the right convex surface and the left concave. Except for its upper and posterior part which is membranous in character, rest of the septum is fleshy. Membranous portion of the septum is hidden from the view due to the medial cusp of the right atrio-ventricular opening. Fibrous base of the heart gives attachment to the muscles of the ventricular system. Structure of the heart consists of myocardium covered with the epicardium outside and the endocardium inside. The muscles of the atria and ventricles are not continuous with the exceptions of the atrio-ventricular bundle. This grants the power of independent contraction to the chambers. Fibrous base of the heart presents four openings. Right and the left atrio-ventricular openings occupy the posterior part of the base of the respective side, while the anterior part presents the pulmonary opening lying in front of the aortic opening. Fibrous ring around the opening acts as the support for the cusps of the valves and prevents them from getting incompetent. Electrical isolation of the SA node and AV node is due to the fibrous skeleton of the heart. The fibrous base of the heart presents further sub-divisions namely the right and left fibrous trigones, the septum membranecum and the conus ligament (Tendon of the infundibulum). Large part of the fibrous base between the mitral and tricuspid opening behind the aortic opening is known as trigonum fibrosum dextrum. Part of the fibrus tissue between the mitral opening behind and the aortic infront is known as trigonum fibrosum sinistrum. (Dictionary meaning of the word dextrum means the right and sinistrum means the left). The septum membranecum extends further into the interior of the heart to form the membranous portion of the interventricular septum. The membranous part of the interventricular septum is the common site for interventricular septal defects (Figures 130 and 134).

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Figure 131 Superficial group of ventricular musculature

Musculature of the Ventricles: Superficial Group:

Deep Group: Conducting System of Heart (Figure 132):

AV Node:

Arrangement of the musculature of the atria: Atrial musculature is arranged into three groups. 1. Superficial group: These fibres run transversely enclosing both the atria. Some of the fibres pass into the interatrial septum. 2. Deep group: They are distinct and separate for each of the atrium. They are attached to the fibrous atrioventricular rings and run from the anterior to the posterior aspect of the respective atria (Figure 131). 3. They are grouped around the orifices of the veins, opening into the atria and round the fossa ovalis in a circular fashion. This group is not separately classed by some of the authors. They consider it to be a part of the deep group. The musculature of ventricles is arranged into two groups namely the superficial and the deep. Fibres arising from the right fibrous atrio-ventricular ring pass towards the apex, turn inwards and enter the papillary muscles of the left ventricle. Fibres arising from the left fibrous atrio-ventricular ring pass towards the apex and turn inwards and enter the papillary muscles of the right ventricle. This classical course of the right and left fibres results in crossing near the apex. The deep group presents horizontal ‘S’ shaped arrangement. Loop A surrounds the right ventricle and the loop B the left ventricle. It consists of the specialised cardiac muscle. It presents the SA node and the AV node, AV bundle of His, and its two limbs the right and the left which end in the Purkinje fibres. The SA node is placed at the upper end of the cresta terminalis below the opening of superior vena cava. It is made of special type of cardiac muscle fibres which show striations. The SA node, being the nodal point of genesis of waves of contraction of the heart, has been labelled as the “Pace-maker of the heart”. It is situated in the right atrium just above and to the left of the opening of coronary sinus. The fibres pass through inter-atrial septum and reach the membranous part of the inter-ventricular septum. This part of the bundle in the inter-ventricular septum is known as bundle of His. On the right, right bundle branch passes through the modarator band and presents as the Purkinje’s fibres. Why there is the specialised conducting system for the heart ? Propagation of the impulse is more rapid and effective due to the presence of specialised conducting system. It is obvious that the impulse

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Figure 132 Showing conducting system of the heart

Journey of an Impulse:

Myocardium:

Acute Myocarditis: Cardiomyopathy:

Coronary Arteries (Figure 133A):

Right Coronary Artery (Figures 133B and 135):

would have taken time and the force of contraction would have been less effective if it were for the impulse to travel along the musculature. Journey of an impulse from the SA node to the AV node, is through the atrial musculature. It is during this period of delay complete emptying of the atria occur. This explains why the ventricles are isolated and beat at slower rate than the atria after complete sectioning of the stem of the AV bundle. The above condition is known as heart block. During such a state atria are beating at the rapid rate as they are still under the control of the SA node. Muscle fibres of the myocardium are short, branched, striated and present central nucleus. Cytoplasm presents transverse dark lines. They are known as inter-calated discs, and have properties of both the skeletal and the smooth muscles. Is the inflammation of the myocardium due to infections including viral. There is impairment of contraction of myocardial muscles of the ventricles leading to left and later the right ventricular failure. It is of three type (1) dilated, (2) restorative and (3) hypertrophic. They can be diagnosed by Dopplers echo-cardiograph. CT Scan, MRI and endocardial biopsy. (Dictionary meaning of the corona is a ring of light around the sun or the moon.) Coronary arteries are peculiar in three respects. 1. Although they are the medium size arteries, their structure is like the large arteries. 2. All arteries fill during systole, while the coronary arteries fill during diastole. 3. For all practical purposes coronary arteries are physiologically end arteries. The right coronary artery arises from the anterior aortic sinus and appears on the sterno-costal surface of the heart between the pulmonary trunk on the left and the right auricle on the right. Its course is directed

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Figure 133A Showing coronary arteries

Figure 133B Schematic diagram showing coronary arteries and how they can be drawn on the image of the Thomas splint

Figure 134 Arrangement of the cardiac muscles at the apex of heart below and fibrous ring above

vertically downwards in the anterior part of the right atrio-ventricular groove. It runs further on the posterior aspect of the heart in the posterior part of the right atrio-ventricular groove and anastomoses with the circumflex, the branch of the left coronary. Right coronary artery supplies right atrium, right ventricle, part of the left atrium, left ventricle and the inter-ventricular septum. Branches of right coronary artery (Figures 135 and 136): 1. Right conus artery 2. Anterior inter-ventricular branches: They are two to three in number. 3. Marginal artery: It is the largest branch which follows the inferior border of the heart reaching the apex of the heart. 4. Posterior inter-ventricular branches: They supply the diaphragmatic surface of the right ventricle.

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Figure 135 Showing blood supply of SA and AV nodes from the right coronary artery

Figure 136 Showing abnormal branch of the left coronary artery supplying SA nodes

Left Coronary Artery: Branches (Figures 133 and 135):

5. Posterior inter-ventricular branch : It runs in the posterior interventricular groove, but stops at the apex of the heart. The anterior inter-ventricular branch of the left coronary artery supplies apex of heart. When the posterior interventricular branch comes from the right coronary artery it is known as the “Right Coronary Dominence” which is present in 90% of the cases. 6. It supplies the right and the left ventricles including the inferior surface of the heart and the posterior part of the inter-ventricular septum. 7. Right coronary artery supplies most of the right ventricle except the small part of the right ventricle situated on right side of the anterior inter-ventricular groove. 8. Sino-atrial branch: It arises from the right coronary artery near its origin and passes to the right towards the superior vena cava where it forms an arterial circle. Left coronary artery arises from the left posterior aortic sinus and appears on the sterno-costal surface of the heart between the pulmonary trunk on the right and the left auricle on the left. Near its origin it gives the circumflex and the anterior interventricular branches. 1. Anterior inter-ventricular branch (descending): It runs in the anterior interventricular groove and goes to the apex of the heart, turns around and supplies the apex. It enters the inter-ventricular septum to anastomose with the right coronary artery. Left coronary artery ends at the apex of the heart in 33% of cases. It supplies the right and the left ventricles and the anterior part of the inter-ventricular septum.

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Right Coronary Dominance: Left Coronary Dominance: Clinical:

Myocardial Ischemia: Myocardial Infarction:

Comment: Investigations for Diseases of Heart:

2. Diagonal branch: It arises near the origin between the circumflex and the anterior intervertebral branches. 3. Circumflex branch: It runs in the anterior part of the left atrioventricular groove and enters the posterior part of the groove, after winding the left border of the heart. It anastomoses with right coronary artery. In fact it is the continuation of the left coronary artery. 4. Left marginal 5. Anterior ventricular 6. Posterior ventricular 7. Atrial 8. And to the right lower branch of bundle of the His. Note: Left coronary artery supplies the diaphragmatic surface of both the ventricles. In 90% of the cases the posterior inter-ventricular branch arises from the right coronary artery. It is known as the right coronary artery dominance. (“Right is might”). In this case the posterior inter-ventricular branch arises from the circumflex branch of the left coronary artery. Being functional end arteries, their micro-anastomosis is unable to supply myocardium in cases of the large block (thrombus) and results in myocardial infraction which can be fatal due to complications like arrhythmias or pump failure (Congestive cardiac failure). Gradual narrowing of the coronaries due to the atheroma reduces blood supply to the myocardium giving pain in pre-cardial area radiating along the inner aspect of the left arm. The blockage of the blood supply to the myocardium leads to the myocardial infraction. Plasma enzymes estimation such as creatine kinase (CK) and (CKMD), tropamin T and 1 are done. Creatine kinase (CK) starts rising after 4 hours, reaches the peak after 12 and starts declining after 48 hours. Myocardial infraction is the forerunner of the deaths. 1. Plane radiogram of the chest: It gives idea about the size of the heart (Cardio-megaly). 2. Straightening of the left border of the heart is seen in mitral stenosis due to enlargement of the left atrium. 3. Angiography: The cardiac catheter is introduced either through the femoral or the radial arteries under local anesthesia and the tip of the catheter is guided towards the coronary openings and the dye is injected. It is the interpretation of the angiogram that counts for which the knowledge of the coronary arterial tree and pattern of branching must find the permanent place in the memory of the clinician. One should learn to read the ECG. 4. Angioplasty: Coronary artery is dilated with the help of the balloon. 5. Stenting of the coronaries: At the site of block after angioplasty a stent is placed. Medicated stent is preferred for the purpose. 6. Coronary bypass surgery (Figure 137): Coronary bypass is done on the beating heart by the sternum splitting incision in the midline. (Sternatomy). Precaution is taken not to injure the left brachio-cephalic vein. Pericardium is opened and the left internal thoracic mammary artery (LIMA) is anastomosed to the coronary beyond the block. The long saphenous vein and the radial artery are also favoured. Thrombosis of the by-pass in the long saphenous vein is due to its

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Figure 137 Diagram showing coronary bypass

Cardiac Pain:

Cardiopulmonary Resuscitation:

Traumatic Asphyxia (Suffocation):

thin wall. Internal thoracic mammary artery has three merits in selecting for the coronary by-pass surgery. 1. Proximity. 2. Length 3. Elastic tissue in the vessel wall Unknown: The endothelium of the internal thoracic mammary artery releases some chemical substance which prevents athero-sclerosis (Cholesterol Preventing Substance) (CPS). 7. Digital subtraction angiography: Before injection of the dye X-ray is obtained. It is followed by the angiography and the X-ray shadows are substracted from the picture. This gives only the picture of the coronary arteries and their pattern clearly. Abnoxus metabolites accompanied by the anoxia causes cardiac pain. It varies from mere discomfort to the crushing pain accompanied by the sweating. Pain is carried by cardiac sympathetic nerves to the posterior roots of the upper four spinal nerves. Upper four spinal nerves give referred pain in the skin of the pre-cardial area radiating along the left upper arm. Pain is also felt in the neck. Diaphragmatic surface of the heart and the epigastric region are innervated by seventh, eighth and ninth spinal nerves. In myocardial infarction involving the inferior surface of the heart gives referred pain similar to the peptic oesophagitis. This fact must be remembered by the clinician, as I have seen the patient of myocardial infraction having severe pain in the epigastrium disposed by giving the tablet of Gelusil (antacid). Restarting of the stopped heart was supposed to get revived by its compression between the sternum and the vertebral column. However it is not true. In this process heart acts like the conduit (like a dead tube) and the sternum and thorax act like the pump. During compression blood goes out as the intra-thoracic pressure is raised and when released the blood returns to the heart from the venous end. This is known as external cardiac massage. The external cardiac massage if done vigorously may cause fracture of the sternum and the contusion of the heart. The sudden depression of the sternum and costal cartilages due to fracture, raises the intra-thoracic pressure resulting in the compression of veins along with the left atrium. This leads to throwing of the blood out of the chest and results in congestion of the veins of the neck, prominent eyes and synosis of the lips and the tongue. Venous drainage of the heart: 1. Coronary sinus 2. Great cardiac vein

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Coronary Sinus (Figures 138 and 138A):

Great Cardiac Vein: Figure 138 Showing coronary veins and the coronary sinus

Figure 138A Veins of the heart (schematic)

3. Middle cardiac vein. 4. Small cardiac vein. 5. Oblique vein of the left atrium. 6. Vena cordiminimae. 7. Number of small unnamed veins. 8. Anterior cardiac veins. Coronary sinus lies in the posterior aspect of the left atrioventricular groove. It forms the lower border of the oblique sinus of the pericardium. Left extremity of the coronary sinus receives the great cardiac vein while its right end opens into the right atrium at the coronary orifice. Blood in the left coronary artery and the coronary sinus run in the same direction. The coronary sinus gets the following veins: 1. Great cardiac vein 2. Middle cardiac vein 3. Small cardiac vein 4. Vein of the left ventricle and number of small veins. 5. Oblique vein of Marshal 6. Anterior cardiac vein 7. Thebacian veins. The great cardiac vein begins at the apex of the heart and runs upwards in the anterior interventricular groove along with the anterior interventricular branch of the left coronary. It turns round the left border of

Heart

Small Cardiac Vein: Middle Cardiac Vein: Oblique Vein (Vein of Marshal):

Anterior Cardiac Veins: Vena Cordiminimae (Thebesian Veins): Clinical:

Blood Supply of Valves: Nerve Supply of the Heart:

Cardiac Plexuses (Figures 148 and 149):

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the heart with the left coronary artery, (circumflex) reaches the posterior part of the left-atrio-ventricular groove and joins the coronary sinus. The small cardiac vein follows the lower border of the heart comes to the right border and turns around it to reach the posterior atrioventricular groove. It opens into coronary sinus near its termination. The middle cardiac vein begins at the apex of the heart follows posterior interventricular groove alongwith the posterior interventricular branch and opens in the coronary sinus. The oblique vein of Marshal runs obliquely downwards and slightly to the right on the posterior surface of the left atrium and meets the coronary sinus. It is the representative of the terminal portion of the embryonic left superior vena cava. There are the small veins situated on the anterior surface of the right atrium and open into the right atrium directly. They directly open in the right atrial cavity by the small openings. These veins anastamose with the coronary venous system. The valve is situated at the junction of the great cardiac vein and the coronary sinus. Openings of the small cardiac veins may have valves. The procedures employed for revascularization : 1. By producing the pericardial adhesions: This helps in the development of the collateral circulation between coronary arteries. 2. Use of omental grafts or muscle grafts: 3. Internal mammary thoracic artery was buried in the musculature of the heart. 4. By bypassing a block with the help of venous graft. 5. Angioplasty 6. Stenting 7. Use of radial artery as the by-pass graft. Note: Number 1 to 3 are almost historical. When the long saphenous vein is used as the by-pass graft, it has to be reversed and tasted for the patency due to the presence of valves. Only 3 mm area near base of the valve has blood supply while the rest is avascular. Heart is innervated by the nerves derived from the vagus and sympathetic. Out of these, the vagal fibres are mainly preganglionic, parasympathetic, while the sympathetic fibres are postganglionic. If sympathetic nerves are stimulated the rate and force of contraction of the heart increases. On the other hand stimulation of vagus nerve decreases the force and the rate of contraction of the heart and may cause cardiac arrest. They are arranged in two sets: a. The superficial and b. The deep. Purkinje fibers form the sub-endothelial plexus. They are long and pale. They show striations at their margins and they have double nuclei. Damage to the conducting system of the heart leads to the cardiac arrhythmia. 1. Superficial cardiac plexus (Figures 148 and 149): Lies in the concavity of the arch of aorta and receives left superior cervical cardiac branch of the sympathetic and left inferior cervical branch of the vagus. 2. Deep cardiac plexus: It lies in front of the bifurcation of the trachea. It receives all other cardiac branches of the sympathetic of both the

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Neurological Control of the Heart:

Clinical Anatomy of the Nerve Supply of the Heart:

Lymphatic Drainage of the Heart:

Separation of Bulbus Cordis and Truncus Arteriosus: Development of Atria:

sides. In addition to this it also receives rest of the cardiac branches of the vagi of both the sides. Although the two cardiac plexuses are described as the separate entities, they are one. Superficial cardiac plexus is connected with the left anterior pulmonary plexus and the deep one is connected with both the anterior pulmonary plexuses. These plexuses continue further along the coronary arteries. There are small and well defined ganglia in the superficial plexus. (Cardiac ganglia of Wrisberg). Parasympathetic is from of the vagus. It is the cardiac inhibitor and its stimulation brings down the heart rate. Sympathetic supply is from the upper two to four thoracic sympathetic ganglia. Stimulation of sympathetic increases the pulse rate and also dilates the coronaries. (Sympathetic accelerates heart rate and dilates the coronaries). In an attempt to relieve the pain in angina pectoris various surgical methods have been tried: 1. Sectioning of the posterior roots of the upper five thoracic nerves. 2. Removal of the upper part of the thoracic sympathetic chain. 3. Injection of alcohol into the sympathetic chain. 4. Removal of the nerve plexus around the coronaries. Beneficial effects after sympathectomy : 1. Increases the coronary circulation. 2. Helps in relief of pain (Pain fibres travel alongwith sympathetic nerves). 3. Increases the coronary circulation and helps in reducing the ischaemia, which itself is the cause of the pain. The lymph vessels of the heart are arranged in two sets namely the superficial and deep. The deeper set lies under the endocardium and superficial under the visceral pericardium. Deep plexus opens in the superficial plexus. From the superficial plexus, right and left lymph trunks arise; the left trunk drains into the inferior tracheobronchial lymph nodes. Right trunk mainly drains in the right atrium and diaphragmatic surface of right ventricle. It goes to the lymph nodes near the brachio-cephalic vein situated on the left side of the mid-line. Note on development of interventricular septum : The interventricular septum develops from the three sources – i. Interventricular septum proper – It forms muscular part. ii. Endo-cardial cushion – forms membranous part. The ventricular septal defects commonly occur in the membranous part of the inter ventricular septum. iii. Right and left bulbar ridges. Bulbs cordis gets absorbed into the right ventricle to form the infundibulum and the aortic vestibule of the left ventricle. Truncus arteriosus is divided into the aorta and the pulmonary trunk by means of the spiral aortico-pulmonary septum. Right atrium develops from three sources : 1. Atrium proper and 2. Sinus venosus. 3. Right atrio-ventricular canal. Left atrium develops from two sources : 1. Atrium proper. 2. Absorption of pulmonary veins.

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ANOMALIES OF THE HEART Dextrocardia:

Tetralogy of Fallot:

Surgical Treatment of Tetralogy of Fallot:

Surface Anatomy of Heart (Figures 139 and 140):

Figure 139 Showing surface marking of heart

Right side of the heart goes to the left and the left comes to the right. In this case the saying that the “Mediastinum seen from the right is blue and from the left is red is totally reversed. 1. Ectopia cordis : The heart is seen from the front as the anterior thoracic wall including the sternum fail to develop. 2. Stenosis (Narrowing) : It can affect aortic or pulmonary openings. 3. Septal defects : Atrial and ventricular (ASD, VSD). 4. Patent truncus : It is due to failure of the development of the spiral septum. There are four components: (Tetra means four) The incidence of tetralogy of Fallot is 10%. It has 1. Pulmonary stenosis 2. Inter-ventricular septal defect. 3. Over-riding of the aorta. 4. Hypertrophy of the right ventricle. Due to pulmonary stenosis more blood goes to the aorta. Blood being partially saturated cyanosis appears. Squatting compresses the femoral and the popliteal arteries, increasing the systemic resistance and the blood goes to the pulmonary circulation, helping the oxygenation. Cynosis, lethargy, tiredness are the symptom. Cyanosis being most prominent and easily detectable. Aim of surgical treatment is to divert the systemic blood to the pulmonary circulation. 1. Blalock–Taussig: The subclavian artery is anastomosed to the pulmonary artery. 2. Waterston: The ascending aorta is anastomosed to the right pulmonary artery. 3. Potts anastomosis: The descending aorta is anastomosed to the left pulmonary artery. Upper border of the heart is marked by joining the point situated on the upper margin of the third right costal cartilage to the point situated on the lower border of the second left costal cartilage 1 cm away from the sternal margin. Right border of the heart can be marked by joining the point on the upper border of the right third costal cartilage to the point

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Figure 140 Surface marking of valves: A. On the lower border of the left second costal cartilage 1 cm away from sternal margin, B. On the upper border of the right third costal cartilage 1 cm away from sternal margin, C. On right 6th costal cartilage 1 cm away from sternal margin, D. On the 5th intercostal space 9 cm to the left of sternal margin. Connect A with B, B with C, C with D and D with A right and left borders are convex to the right and left

on the sixth costal cartilage 1 cm away from the sternal margin. Lower border of the heart is marked by the point on the right sixth costal cartilage to the point situated 9 cms away from the mid-sternal line in the fifth intercostal space. (i.e. medial to the left inter-clavicular plane). The left border of the heart is drawn by joining the point in the left fifth intercostal space to the point located on the lower margin of the second left costal cartilage 1 cm away from the sternal line. Please note that the right and the left borders are drawn with convexity pointing on the respective sides (Figures 139 and 140).

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THORACIC AORTA It arises from the left ventricle, runs upwards forwards and to the right and reaches the level of right second costal cartilage. At this point the ascending aorta ends the arch of aorta begins. The arch of aorta runs to the left and backwards to the left side of the fourth thoracic vertebra, where it descends as the descending thoracic aorta (Figure 141). Figure 141 Showing arch and descending thoracic aorta

Ascending Aorta (Figure 142):

Figure 142 Showing vagi of right and left with recurrent laryngeal nerves and their relation to right subclavian artery and the arch of aorta

Following are the anterior relations of the ascending aorta. 1. Pulmonary trunk 2. Left lung and the pleura. 3. Sternum 4. Infundibulum 5. Auricle of right atrium 6. Remains of thymus at the higher level.

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Posterior Relations (Figure 143):

1. 2. 3. 4. 5.

Right pulmonary artery. Right atrium. Right bronchus. Transverse sinus. Left atrium.

Figure 143 Horizontal section at level of fourth thoracic vertebra viewed from above

Left Relations:

Right Relations:

Arch of Aorta (Figures 141 to 143):

Origin Course and Termination of the Arch of Aorta:

Relations at the Commencement: Left Relations:

1. 2. 3. 4. 1. 2. 3. 4.

Bifurcation of the pulmonary trunk. Left lung. Pleura. Left atrium Superior vena cava. Right atrium Right phrenic nerve. Right pleura and lung. Right and left coronary arteries arise from its proximal part of the aorta. The right from the anterior aortic and the left from the left posterior aortic sinuses. It has already been stated that the proximal part of ascending aorta is enclosed in the common tube of serous pericardium alongwith the pulmonary trunk and forms the anterior boundry of the transverse sinus of the pericardium. The fibrous pericardium gets fused with the outer coat of the aorta. If the section at the level of the fourth thoracic vertebra is studied, understood and drawn by the student himself or herself. The relations of this important structures of the mediastinum at the 4th thoracic level are simplified. At the same time I personally would like to advise the students to draw this particular section as seen from above. This section is the master key for the relations of the structures in the thorax. The arch of aorta begins at the level of right second costal cartilage and turns backwards and to the left under cover of the manubrium sterni. It ends at the left side of the fourth thoracic vertebra where the descending part begins. During its course to the left side it goes more posteriorly and appears as if it is moulded on the vertebral column. By virtue of this fact it projects beyond the left margin of the sternum and can be identified in the radiograph of the chest as the “Aortic Knuckle”. It is more prominent in the old aged persons. It is placed superficially and is related to the lower half of the manubrium sterni. However, anterior margins of the right lung and pleura intervene between the sternum and the aorta. 1. Left pleura and the left lung. 2. Left phrenic and the left vagus.

Thoracic Aorta

Right Relations:

Inferior Relations (Figure 144):

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3. Nerves of superficial cardiac plexus (Left superior cervical of sympathetic) (left inferior cervical of the vagus). 4. Left superior intercostals vein: This particular vein is formed by the union of the intercostal veins from the second and the third intercostal spaces and runs on the left side of the arch it crosses the vagus superficially and itself gets crossed by phrenic nerve, on way to its termination in the left bracheo-cephalic vein. 1. Trachea (Right vagus, Azygos vein). 2. Oesophagus 3. Left recurrent laryngeal nerve 4. Thoracic duct and fourth thoracic vertebra. 1. Pulmonary trunk and its bifurcation 2. Ligamentum arteriosum. 3. Left recurrent laryngeal nerve 4. Root of the left lung (Left bronchus, left pulmonary artery, two left pulmonary veins, anterior and posterior pulmonary plexuses and lymph nodes). 5. Superficial cardiac plexus.

Figure 144 Showing course left recurrent laryngeal nerve and ligamentum arteriosum

Superior Relations of the Arch of the Aorta:

Histology of the Aorta:

Blood Supply of the Wall of Aorta:

1. Its three branches: the brachio-cephalic, the left common carotid, and the left subclavian arteries. 2. Thyroidea ima artery when present. 3. Left branchio-cephalic vein passes downwards and to the right, lying above the convexity of the arch of aorta crossing its three branches from the left to the right superficially just below the supra-sternal notch of the manubrium sterni. It consists of three coats 1. Intima, 2. Media 3. Adventitia. 1. Tunica intima (Figure 145): There are flattened and oval cells lining the interior of the vessel. This layer has small amount of connective tissue under-neath the endothelium. Immediately outside the subendothelial layer there is the fenestrated elastic membrane. 2. Tunica media: Tunica media is made of concentrically arranged elastic membranes separated from each other by the fibrous tissue. The fibrous tissue also contains some plain muscle cells. 3. Tunica adventitia: It is made of the fibrous tissue with some elastic fibres. Note: Elastic recoil of the aortic wall helps in propogation of the blood towards the periphery during the phase of diastole. Small vessels arise from the nearby vessels or from the branches of the aorta itself. They supply the adventia and outer part of media. Small

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Figure 145 Histology of the aorta (Schematic)

Lymphatics:

veins accompany these nutrient vessels and drain into the nearby veins. The nutrient vessels of the large artery are known as the vasa-vasorum. They are present only in the outer coat.

DEVELOPMENT Arch of Aorta (Figure 146) Aid to Memory:

Right Subclavian Artery: Left Subclavian Artery:

Clinical:

Figure 146 Showing development of arch of aorta

The arch of aorta develops from the aortic sac, left born of aortic sac, left fourth arch and part of the left primitive dorsal aorta. 1. The word arch has four alphabets. 2. Arch lies at the fourth thoracic vertebra. 3. Arch has four branches. 4. Arch develops from four sources. i.e. aortic sac, left horn of the aortic sac, left 4th arch artery and left dorsal aorta. It develops from two sources, proximal part from right fourth arch artery and the distal from the seventh cervical inter-segmental artery. Brachiocephalic artery develops from the right horn of the aortic sac. The left subclavian artery develops from the left seventh cervical inter segmental artery (Figures 151 and 152). As an anomaly right subclavian artery arises from left side of aortic arch. It passes to right behind oesophagus and may cause dysphagia (Dysphagia Lusoria). Common carotid artery develops from the proximal part of the third arch artery. Ascending aorta and the pulmonary trunk develop from truncus arteriosus. Descending aorta develops from left dorsal aorta below the fourth arch. Localised dilatation of the vessel is known as aneurysm. It is of two types true and the false when all the three components of the wall are involved it is known as true aneurysm. When one layer is involved it is known as false aneurysm. Spliting of the aorting wall by the aneurysm is known as dissecting aneurysm.

Thoracic Aorta

Coarctation of Aorta (Figures 150 and 153):

Ligamentum Arteriosum (Figures 147, 147A and B):

Clinical:

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Aneurysm is commonly due to the syphilitic infection. However, the incidence has gone down due to control of sexually transmitted diseases (STD). Aneurysm of the arch of the aorta leads to various symptoms, signs and the complications. 1. Pressure on the left recurrent laryngeal nerve leads to hoarseness of the voice. 2. Pressure on the trachea leads to dry cough. 3. Pressure on the oesophagus leads to dysphagia. 4. Pressure on the sternum causes erosion and destruction of the bone with retrosternal pain. 5. Tracheal tug can be felt by keeping the fingers on the trachea in the suprasternal notch due to the transmission of the pulsations of the aortic aneurysm 6. Rupture of the aneurysm leads to various complications. Its ruptures in the trachea causes haemoptysis; (coughing of blood), in the oesophagus it leads to haematemesis (vomiting of blood). Rupture of the aneurysm into the pericardium and the pleural cavities leads to the haemopericardium and the haemothorax respectively. It is obvious from the above clinical facts that the signs, symptoms and complications of this aortic aneurysm can well be explained and remembered on the basis of the anatomical relations alone. It is the narrowing of the part of the aorta. In coarctation of aorta there is gross difference between the blood pressure in the arms and the legs. Collateral channel open in an attempt to drive the blood from the portion proximal to the coarctation to the distal. This results in enlargement of the intercostal arteries arising from the descending thoracic aorta and the internal thoracic mammary arteries. It gives notched appearance to the lower borders of the ribs in X-Ray. In the foetal life pulmonary trunk is connected to the aortic arch by the short channel known as the ductus arteriosus. By virtue of this connection, the blood from the right side of the heart directly enters the aortic arch. At birth with the appearance of the pulmonary respiration, the blood is diverted to pulmonary circulation and the short circuit which existed in the form of the ductus arteriosus gradually gets obliterated and remains the fibrous cord known as the ligamentum arteriosum. Embryologically ligamentum arteriosum represents dorsal end of the left sixth aortic arch. To the left of the ductus arteriosus is the left recurrent laryngeal nerve and the superficial cardiac plexus on the right. Expansion of the lungs with the first act of respiration the ductus arteriosus undergoes the twist which is important for the obliteration. Contraction of the smooth muscles of the wall of the ductus and the proliferation of the endothelium are credited for the closure of the ductus. Oxygen tension and prostaglandins play an important part in process. 1. Some remaining facts about the aneurysm : Lower half of the manubrium sterni can get completely eroded resulting in appearance of the pulsating swelling under the skin in the presternal region. I know the case of spontaneous rupture of such an aneurysm. There are cases of an aneurysm pulsating under the skin, mistaken for an abscess and unfortunately incised. 2. Patent ductus arteriosus: Failure of obliteration ductus arteriosis is known as the patent ductus arteriosis. Functional closure occurs

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Figure 147 Showing ligamentum arteriosum

Figure 148 Superficial cardiac plexus

Figure 149 Showing cardiac and pulmonary plexuses

Figure 150 Showing coarctation of aorta

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Figure 150A Foetal circulation (schematic)

Foetal Circulation (Figure 150A):

Figure 151 Showing formation of abnormal right subclavian artery and non-recurrent right laryngeal nerve and left recurrent laryngeal nerve

immediately after birth. Anatomical closure occurs due endothelial proliferation of the wall of the ducts within three months of after birth. This is the commonest anomaly of amongst the acynotic congenital heart diseases. Pressure in the aorta is more than pressure in the pulmonary artery which leads to increased blood supply to the lungs leading to dilatation of pulmonary vessels with increased pulsations. (Pulmonary plethora – Hilar Dance) (left to right shunt). Clinically the machine like murmur is heard. It can be treated by the ligation of the patent ductus after thoracotomy. 3. In X-ray of the chest the prominence of the arch can be seen along the left border of the heat known as aortic knuckle. The foetal lungs are non-functioning. The job of oxygenation of the blood is done by the placenta from which umbilical veins bring blood to the inferior vena cava via ductus venosus. Before reaching the ductus venosus this vein passes through the substance of the liver. Only small part of the blood circulates through the liver and makes its entry into the inferior vena cava via the hepatic veins. Through the inferior vena cava blood enters the right atrium and form there to the left atrium through formen ovale and finally enters the left ventricle. The mixed blood of the left ventricle enters the aorta.

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Figure 152 Showing formation of abnormal right subclavian artery

Figure 153 Showing collateral circulation in coarctation of aorta

Descending Thoracic Aorta (Figure 154):

On the other hand the blood (venous) brought by the superior vena cava enters the right atrium, then the right ventricle and leaves through the pulmonary trunk. Form the pulmonary trunk it enters the aorta through the ductus arteriosus. It is interesting to note but difficult to imagine that the arterial and the venous blood are flowing through the right atrium without appreciable mixing. It is to be appreciated here that the pure blood from the left ventricle enters the aorta and flows through its great vessels (brachio-cephalic), left common carotid and left subclavian arteries). On the other hand deoxygenated blood from the right ventricle enters the pulmonary trunk and enters the portion of the aorta, distal to the left subclavian artery through the ductus arteriosus. Naturally this part gets an impure blood and the part proximal to the subclavian gets pure blood. During foetal life pressure in the right atrium is more than the left. At birth due to the non-arrival of the blood from the placenta, through the umbilical veins and ductus venousus, the pressure falls. At the same time due to the opening of the pulmonary circulation left atrium gets more blood from the lungs through the pulmonary veins. This increases the pressure in the left atrium and helps the closure of the foramen ovale. It begins on the left side of the body of the fourth thoracic vertebra, the point where the arch ends. It runs downwards slightly in the right and continues till it reaches the median plane at the level of the twelfth thoracic vertebra. It leaves the thorax to enter the abdomen by passing

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Figure 154 Showing arch and descending thoracic aorta its branching pattern

Anterior Relations:

through the aortic opening, under the median arcuate ligament. During its downward course it inclines forwards away from the vertebral column. The oesophagus has to go to the left and the descending thoracic aorta to the right leading the crossing where the descending thoracic aorta goes behind the oesophagus. The crossing of the descending thoracic aorta and the oesophagus lies behind the left atrium. The oesophagus forms the direct posterior relation of the left atrium. Oesophageal compression due to enlargement of the left atrium in mitral stenosis leads to dysphagia. 1. Root of the left lung with structures in it, pulmonary plexus and pulmonary ligament. 2. Pericardium (left atrium, oesophagus) 3. Diaphragm. 4. Caudate lobe of the liver. It is separated from the aorta by the diaphragm. Right relations: 1. Bodies of the thoracic vertebrae and the anterior longitudinal ligament. 2. Oesophagus as already explained. 3. Vena azygos and the thoracic duct. 4. Mediastinal pleura of the right side only in the lower part of the posterior mediastinum.

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Kadasne’s Textbook of Anatomy (Clinically Oriented) Posterior Relations : 1. Left lung and the pleura. 2. Hemiazygos veins. Relations on the left : 1. Left lung and the pleura. 2. Oesophagus in lower part.

Branches:

Left Posterior Intercostal Arteries: Course of the Posterior Intercostal Artery (Figure 155):

Figure 155 Showing intercostal arteries in the intercostal space

There are nine pairs of the posterior intercostal arteries. They are distributed to the lower nine intercostal spaces. As the descending thoracic aorta is on the left, its right posterior intercostals arteries cross the midline, pass in front of the bodies of the vertebrae, behind the oesophagus, thoracic duct and the azygos vein, from the left to the right. The descending thoracic aorta has four sets of branches, namely the ventral, dorsal, lateral and the terminal. The ventral branches are, the ciliac, superior and the inferior mesenteric arteries. Dorsal branches are the lumbar arteries and the median sacral artery. Amongst the lateral are the inferior phrenic, the middle supra-renal, the ovarian or testicular arteries and the terminal branches, the common iliac arteries. They pass along the sides of the vertebrae under cover of the left lung and the pleura. Left superior intercostal vein crosses the upper two arteries. After its origin from the back of the descending thoracic aorta it runs across the posterior part of the intercostal space obliquely upwards and reaches the point at an angle of the rib. During its further course it lies in the subcostal groove below the intercostal vein and the nerve. In the subcostal groove artery lies between the vein above and the nerve below: (VAN) (from and above downwards) (Figure 156) However, in the upper spaces the nerve lies above the artery in its initial course, however it soon assumes the position and lies below the artery. Each vessel anastomoses anteriorly with the anterior intercostal branch of the internal thoracic mammary or the musculophrenic arteries. It is important to note that the third intercostal artery anastomoses with the superior intercostal artery. By virtue of this connection, it may form the chief source of blood supply to the second intercostal space. Posterior intercostal arteries of the tenth and eleventh spaces reach the anterior ends of the intercostal spaces and continue in the anterior abdominal wall. Posterior intercostal artery of each space gives the collateral branch which anastomoses with the branch of the internal thoracic mammary artery independently.

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Figure 156 Showing arteries of the intercostal space with branches

Dorsal branch (Figure 157):

Collateral Branch:

Figure 157 Showing relations of dorsal branch of spinal artery

Parietal branches of the posterior intercostal arteries (see Figure 148) They are as under : 1. Dorsal branch 2. Collateral intercostal branch. 3. Muscular branches. 4. Lateral cutaneous branch. 5. Mammary branch. 6. Right bronchial artery– Right bronchial arises usually from the right third posterior intercostal artery. However, it may arise from the upper left bronchial artery. The dorsal branch goes to the posterior aspect through the gap, between the necks of the ribs. Medial to it lies the vertebral body and laterally the superior costo-transverse ligament. Its spinal branch supplies the spinal cord, the membranes and the vertebral body after passing through the inter-vertebral foramen. The spinal branch has an anastomosis with the spinal arteries above, below and with the arteries of the opposite side. After giving the spinal artery, the dorsal artery passes above the transverse process of the thoracic vertebra along with the dorsal ramus of the intercostal nerve and supplies the muscles of the back. It gives the cutaneous branch which accompanies the cutaneous branch of the dorsal ramus. Except the lower two intercostal spaces, they are constant. It takes origin from the posterior intercostal artery near the angle of the rib and runs

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Muscular: Lateral Cutaneous Branch: Mammary Branches: Right Bronchial Artery:

along the upper border of the rib below. Anteriorly, it anastomoses with the branch of the internal thoracic mammary or the musculo-phrenic arteries. They anastomose with superior and lateral thoracic arteries. It follows the lateral cutaneous nerve. They arise from the second, the third and the fourth space arteries. Normally it arises from the right third posterior inter-costal artery.

CLINICAL Coarctation of Aorta (see Figure 153):

Subcostal Arteries:

Oesophageal Branches:

Left Bronchial: Mediastinal Branches: Phrenic Arteries (Superior): Clinical:

It is the narrowing of the aorta near the ductus arteriosus. It can be preductal or post ductal. It is due to the process of contraction of muscles of the ductus arteriosus leading to the fibrosis of the aortic wall. There are seven possible causes of the ductal closure. a. Onset of pulmonary circulation b. Rotation of heart which gives twist to the duct c. Spasm due to the nerve stimulations d. Natural process of obliteration e. Endothelial proliferation f. O2 tension g. Prostaglandins. Absence of both femoral pulses and evidence of opening of the collateral circulation, linking the subclavian artery, the internal thoracic mammary and posterior intercostal arteries is seen in the aortogram. The radiograph shows the notching of the inferior borders of the ribs due to the pressure of the enlarged collaterals. The difference in the blood pressure in the upper and the lower limbs is remarkable. Paracentesis is safely done from the lateral aspect of the thorax where, needle should be passed just above the upper border of the rib below or ideally it should be exactly in the middle of the intercostal space between the posterior intercostal artery and its collateral branch. Subcostal arteries arise from the descending thoracic aorta and run below the last rib. They leaves the thorax by passing under the lateral arcuate ligament. During its course in the thorax it lies behind the sympathetic trunk, its branches, the pleura and the diaphragm. They are 4-5 in number and arise from the front of the aorta and course downwards towards the oesophagus. Higher up they, anastomose with branches of the inferior thyroid artery and lower down with the branches of the left phrenic and the left gastric arteries (Figure 158). They are two and arise at the level of the fifth thoracic vertebra below the left bronchus. They are distributed to the lymph nodes and the areolar tissue in the posterior mediastinum. They arise from the lower part of the aorta and supply the of the superior surface of the diaphragm. They anastomose, with the musculophrenic and the pericardio-phrenic, arteries. Aneurysmal dilation of the descending thoracic aorta has tendency to go backwards. Such an expansion, presses on the vertebral bodies, intercostal nerves and eventually the spinal cord. Pressure on the nerves

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Figure 158 Course of oesophagus (side to side curvatures)

X-ray Appearance:

gives rise to the classical radiating pain in the affected intercostal spaces. Anterior shift of the aortic aneurysm causes pressure on the heart, which leads the palpitation. (rapid irregular beating of the heart). X-Ray shows the evidence of absorption of the vertebral bodies and the ribs, but not of the inter-vertebral discs as they are avascular. Clinical diagnosis needs confirmation by the special radiological investigation like an aortography.

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OESOPHAGUS Oesophagus is the muscular tube lined by the stratified squamous epithelium. It begins in the neck at the level of the cricoid cartilage the level of the 6th cervical vertebra, where the pharynx ends and the oesophagus begins. It ends by joining the stomach at the 11th thoracic vertebra after piercing the diaphragm at the level of 10th thoracic vertebra (Figures 159, 160, 163 and 164) Figure 159 Trachea divides on right of midline, hence left bronchus crosses the oesophagus from right to the left anteriorly

Figure 160 Pulmonary trunk divides on the left side of the midline, hence right pulmonary artery crosses the eosophagus from left to right

Aid to Memory:

1. There are ten alphabets in the word oesophagus. 2. Length of oesophagus is 10” (Ten inches). 3. Oesophagus enters the diaphragm at the level of 10th thoracic vertebra. 4. If No.10 cathetar is passed in the stomach of a newborn, and gets obstructed at 10 cm. mark at the lips, diagnosis of oesophageal atresia is almost confirmed. Peculiarity of the oesophagus is that it is devoid of the serous covering except for its 1.5 cm abdominal part, making the malignant growths to get attached to the surrounding structures earlier, leading to dysphagia to the solids and the liquids. The height of misery reaches its peak when the patient cannot swallow his/her own saliva. Normally an individual secretes 1500 cc of saliva in 24 hours. This fact has to be taken in consideration while treating the cases of the dysphagia due to cancer.

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The oesophagus begins in the neck at the lower border of the sixth cervical vertebra. It begins in the midline, however shifts to the left at the root of the neck and regains midline position upto the fifth thoracic vertebra and continues upto the seventh thoracic vertebra. At the level of the seventh thoracic it shift to the left with forward inclination, pierces the diaphragm at the level of the tenth thoracic vertebra to join the stomach (see Figures 159 and 160). 1. The bifurcation of the trachea is on the right, hence the left bronchus crosses the oesophagus from the front. The bifurcation of the pulmonary trunk is on the left, hence the right pulmonary artery crosses the oesophagus from the front. 2. Arch of aorta crosses the left bronchus near the tracheal bifurcation and the oesophagus from the front. 3. In the lower part of the thorax it is the oesophagus which crosses the descending thoracic aorta from the front. 4. There are three constrictions of oesophagus, which are remembered as figures of 15 cm, 25 cm and 40 cm (Figure 161). Figure 161 Showing antero-posterior curvature of oesophagus

Aid to Memory:

They are: a. At 15 cm is the crico-oesophageal junction which is the narrowest part of the gastrointestinal tract, except the lumen of the appendix. b. At 25 cm the arch of aorta and left bronchus. c. At 40 cm oesophageal opening in the diaphragm. Constrictions of oesophagus have the clinical applications of the practical importance, which can be remembered by four capital alphabets. F.I.C.S. (Fellow of the International Collage of Surgeons). F - Foreign bodies get obstructed at the constriction. I - Instrument – while passing the oesophagoscope or the gastroscope. C - Cancer – Constrictions are the sites for the cancer of the oesophagus. S - Strictures develop at the site of constrictions due to corrosive Substance like sulphuric acid or GORD (Gastro-oesophagial Reflex Diseases) due to the incompetence of LOS (Lower Oesophagial Sphincter)

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Kadasne’s Textbook of Anatomy (Clinically Oriented) Curvatures of oesophagus : It has two types curvatures 1. The antero-posterior which follows the curvature of the vertebral column. 2. Two, side to side curvatures both pointing towards the left.

Relation of Oesophagus (Figures 162 to 165):

Figure 162 Showing anterior relations of oesophagus (schematic)

Figure 163 Showing transverse section of the thorax at the level of 8th thoracic vertebra (as seen from above)

Figure 164 Showing relation of oesophagus at the level of the 4th thoracic vertebra

Anterior : 1. Trachea 2. Left recurrent laryngeal nerve 3. Left bronchus 4. Right pulmonary artery 5. Pericardium 6. Left atrium 7. Coronary sinus and the 8. Diaphragm.

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Figure 165 Showing oesophagus and descending thoracic aorta entering abdomen

Posterior Relations of the Oesophagus:

1. Vertebral bodies 2. Ant. Longitudinal ligament. 3. Longus cervicis muscle, only upto third thoracic vertebra with the prevertebral fascia. 4. Azygos vein 5. Hemiazygos veins 6. Thoracic duct. 7. Right posterior intercostal arteries. 8. Oesophageal plexus. 9. Recess of the right pleural cavity which extends between the vertebral column and the oesophagus. 10. Descending thoracic aorta. Right: 1. Mediastinal surface of the right lung and the pleura. 2. Thoracic part of the inferior Vena cava.

Oesophageal Plexus (Figures 166 to 169):

Blood supply of the Oesophagus (Figure 168):

Left: 1. Thoracic duct, 2. Left subclavian artery. 3. Arch of aorta. 4. Descending thoracic aorta, 5. Left Lung with the pleura. Left bronchus crosses the oesophagus from the right to the left, and the right pulmonary artery crosses the oesophagus from the left to the right. It is because of the fact that the trachea divides on the right and the pulmonary artery divides on the left (Figures 159 and 160). It has already been stated that the vagi emerge out of the posterior pulmonary plexus and form the relation with the oesophagus. The nerves branch profusely and form the oesophageal plexus along with the branches of the sympathetic chains. At the lower end of the oesophagus the right vagus forms the posterior gastric nerve and the left forms the anterior gastric nerve. In the neck : Branches of the inferior thyroid arteries the branch of thyro-cervical trunk which is the branch of the subclavian artery. In the thorax : Oesophageal branches of the descending thoracic aorta. In the abdomen : Branches of the left gastric artery the branch of the coeliac artery which arises from the abdominal aorta at the 12th thoracic vertebra.

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Figure 166 Horizontal section of 10th thoracic vertebra showing posterior relation of oesophagus

Figure 167 Relations of the oesophagus at the 5th thoracic vertebra. Note descending thoracic aorta, thoracic duct and azygos vein form posterior relations

Figure 168 Blood supply of oesophagus

Figure 169 Showing right and left vagi with recurrent laryngeal nerves (schematic). Note formation of anterior and posterior gastric nerve

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Figure 170 Lymphatic drainage of oesophagus of lesser curvature

Lymphatic Drainage of the Oesophagus:

Structure of Oesophagus:

Venous drainage: In the neck : Drains into the inferior thyroid veins. In the thorax : Left brancheo-cephalic vein. In the abdomen : It drains into the left gastric vein which joins the portal vein. The venous drainage of this particular portion of the oesophagus is clinically important. Blood from the abdominal portion of the oesophagus drains partly into the azygos and partly into the left gastric vein. The left gastric vein is the tributary of the portal. The lower end of the oesophagus forms one of the important sites of anastomosis between the portal, and systemic circulation. Cirrhosis of the liver causes obstruction of the portal circulation leading to abnormal dilatation of the oesophageal veins (Varices includes elongation, dilatation and the tortuosity of the veins) Rupture of the oesophageal varices causes haematemesis (Figure 170A). Lymphatic drainage is divided in three: 1. Upper 3rd, 2. Middle 3rd, and 3. Lower 3rd. Lymphatics from the upper third go to the paratracheal and the retropharyngeal nodes, from the middle third to the tracheobronchial and the posterior mediastinal nodes and from the lower third of the oesophagus go to the coeliac group of lymph nodes. Although the oesophagus has the external fibrous covering of its own, it does not have the serous coat except for its small abdominal portion. Inside the outer fibrous coat is the muscular coat. It is arranged in two strata: (1)The outer longitudinal, and (2) the inner circular. Longitudinal fibres, if viewed from the posterior aspect, have a peculiar arrangement towards the upper end of the oesophagus below the cricoid cartilage. These fibres diverge from each other, cover the anterior and the lateral aspect of the tube, from the tendon of the oesophagus which gets attached to the lamina of the cricoid cartilage in the midline. Narutally the intermediate space between the two longitudinal fasciculi, is filled with the circular fibres, alone. In the upper third the musculature is made of striated fibres. In the middle third it is made up of mixed fibres (striated and smooth) and in the lower third is made up of purely smooth muscle fibres. Inside the muscular coat lies the submucous coat. Presence of mucous gland, blood vessels, and nerves, is seen in these particular

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Peristaltic Waves:

Ba-swallow – X-ray of the Oesophagus:

The Story of ABC:

layers. Lying inside the submucous coat, is the mucous coat which is the thicker, innermost lining of the oesophagus. It is made of stratified squamous epithelium. Lower down, the muscularis mucous is well formed, at the lower end of the oesophagus and merges with that of the stomach. The stratified squamous epithelium is suddenly changed in the simple columnar epithelium like that of the stomach. The type of mucous glands into the oesophagus belong to the compound racemose type. They are three: 1. Primary: They begin at the crico-oesophageal sphincter and waves help in the act of swallowing. 2. Secondary: They begin at the arch of aorta and help in cleaning the oesophagus. 3. Tertiary: These waves begin at the lower third of the oesophagus and are not the peristaltic waves as such. Secondary and tertiary waves are responsible for the corkscrew appearance of the lower end of the oesophagus in the barium swallow X-Ray of the oesophagus. Ba-swallow – X-ray of oesophagus shows three normal indentations produced by the arch of aorta, bronchus and the cardiac from above downward which can be named as “ABC indentations of oesophagus”. A - Aorta B - Bronchus (Left) C - Cardiac A friend of mine, joined the driving school in U.K. He told me simply with joy that the first lesson of the driving school was the “ABC”. I was surprised to know that the first lession of ABC of driving lasted for 10 to 15 minutes only. On further enquiry, he explained to me that A is for the Accelarator B is for the Break And C is for the Clutch. This prompted me to write the ‘ABC’ of the compression or indentations of the oesophagus as seen in the normal barium-swallow X-ray of the organ. AID TO MEMORY IS NO CRIME, AS THE CAPACITY OF THE BRAIN TO RETAIN WORDS IS LIMITED.

Development of Oesophagus (Figures 172 to 175):

Oesophagus develops from the endodermal tube of the fore-gut proximal to the fusi-form dilatation of the primitive stomach. The tracheal diverticulum lies anterior to the oesophageal tube, only in the upper part, where the oesophageal tube and tracheal diverticulum communicate with each other. Length of the oesophageal tube increases rapidly due to the increase in the size of lung buds and the tailward migration of the heart. Original lumen of oesophageal tube gets partially obliterated, but gets recanalised. If the process of canalisation is defective, it gives rise to congenital atresia of oesophagus (Atresia means failure of canalisation). Cranial-word migation of the ridges separate the tracheal and oesophageal tubes. In cases of incomplete fusion of the ridges, abnormal communication between the larynx and oesophagus or between trachea and oesophagus exists. (Laryngo-oesophageal or tracheaoesophageal fistula).

Oesophagus Figure 171 Showing cardiac sphincter: Lower oesophageal sphincter (LOS)

Figure 172 Development of oesophagus

Figure 173 Tracheooesophageal fistulae their types

Figure 174 Tracheooesophageal fistula with atresia of oesophagus observe air in the fundus of stomach

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Figure 175 Showing tracheooesophageal fistula (type-1) 85%

During early foetal life, interior of oesophagus is lined with the simple columnar epithelium, which may show cilia. This type of epithelium is replaced by stratified squamous type. There is no agreement about the origin of the stratified squamous epithelium of the oesophagus. Two theories are put-forth. 1. Change of the local epithelium from columnar to the stratified (metaplasia). 2. Gradual migration of the epithelium of the buccal cavity.

CLINICAL 1. Atresia : The failure of recanalisation of the lumen of the oesophagus causes atresia. 2. Tracheo-oesophageal fistulae: They are usually associated with the congenital atresia. Various types of tracheo-oesophageal fistulae are described. In type one, upper segment of oesophagus has no communication with the lower of its own. Lower oesophageal segment has a communication with the trachea by means of fistula. It is easy to understand and follow the course of the air into the fundus of the stomach. X-Ray showing evidence of the air in the fundus of stomach of a newborn is strongly suggestive of a tracheooesophageal fistula. However, absence of air does not rule out the condition. 3. Compression : Dysphagia Lusoria (see Figure 151) Retro-oesophageal right subclavian artery can cause dysphagia due to the oesophageal compression and is known as the Dysphagia Lusoria. 4. Carcinoma of oesophagus : Mid-thoracic portion of the oesophagus is the common site for the malignant growths. (50%) 5. Achalasia cardia: Achalasia cardia is due to the absence of the ganglion cells in Auerbach’s plexus in the lower contracted segment of the oesophagus. Barium X-ray of the oesophagus shows rat-tailed appearance. Upper segment of the oesophagus is dialated and fundus of stomach shows no gas. 6. Barrets Oesophagus: It is not the oesophagitis but the change in the character of cells of the lower oesophagus (Metaplasia). Rarely the ulcer may develop in the columnar cells lined part of the oesophagus. 7. Mellory-Weiss Syndrome: In forceful vomiting there is a vertical tear or split in the gastric mucosa leading to the hematemesis. Gastric mucosa gets split in 90% of the cases. 8. Boerhaave Syndrome: Spontaneous perforation of the oesophagus occurs during vomiting when the glottis is closed. It occurs in the lower part of the oesophagus which is supposed to be the weak spot. 9. Hiatus Hernia: (Figures 171 to 178) It can be congenital or acquired. Acquiared hiatus hernia are more common. It is of two types (i) the sliding (ii) and the paraoesophageal or rolling.

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Figure 176 Showing tracheo-oesophageal fistula (type-2)

Figure 177 Showing tracheo-oesophageal fistula (type-3) 12%

Figure 178 Showing tracheo-oesophageal fistula (type-4)

Figure 179 Showing bell type and paraoesophageal (rolling type of) hiatal hernia

GORD is the common factor for the genesis for both the types of hernia. (GORD means Gastric Oesophageal Reflex Disease) Sliding: It is like a bell of a temple or a church. In this type gastrooesophageal junction moves in the thorax through the hiatus along with the stomach. Paraoesophageal (Figure 179): In paraoesophageal type of hernia, gastro-esophageal junction remains static at its own place and part of the stomach rolls in the thorax by the side of the oesophagus. Aid to memory: Diagnosis of hiatus hernia is not easy but HARD. HARD H : Heart-burn A : Anaemia R : Regurgitation D : Dysphagia Note: Signs and symptoms of the hiatal hernia can be remembered by the word HARD. Symptoms in bell type of hernia are more than rolling type of hernia. However dysphagia is a common in rolling type of hernia.

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Fixation of Midthoracic Part of the Oesophagus:

Cardiac Sphincter (see Figure 171):

10. Nut-cracker oesophagus: In this condition the pressure inside the oesophagus goes upto 180 mm Hg, leading to perforation of the oesophagus. 11. Schatzki ring: A ring is formed by the fibrous tissue at the lower end of the oesophagus between the squamous and the columnar part lining the oesophagus. 12. Hyper-peristaltic lower oesophageal sphincter (LOS): In this condition the pressure at the LOS reaches upto 45 mm of Hg with normal swallowing. 13. Barium-swallow of the oesophagus in lateral view shows three indentations from above downwards. 1. Aortic arch 2. Bronchus 3. Cardiac (Left atrium) Oesophagus is fixed to the arch, trachea, left bronchus, pericardium and the left pleura by means of small slips made of smooth muscle fibres. These slips although appear antomically insignificant, their surgical value is undisputed. At the time of mobilization of the oesophagus for resection, these slips are required to be cut carefully. Although the clinical condition known as cardiospasm is well recognised, existence of the anatomical sphincter at the lower end of oesophagus has not been established. Different views are expressed in support of sphincteric action at the lower end of oesophagus: 1. Action of right crus of diaphragm through which the oesophagus passes (pinch-cock action). 2. Angulation between stomach and oesophagus. 3. Oblique fibres of the stomach forming inverted ‘U’ shaped loop at the incisura cardia. 4. Phrenico - oesophageal ligaments. They are well developed and can be identified from the left. 5. Intra thoracic intra-abdominal pressure. 6. Distended fundus of stomach compress the oesophagus.

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THORACIC DUCT AND VEINS IN THE THORAX Thoracic Duct (Figures 180 and 181):

Figure 180 Showing course of thoracic duct

Figure 181 Showing relations of the descending thoracic aorta, thoracic duct and the azygos vein with the oesophagus

It is the greatest lymphatic channel of the body having a length of 45 cm. It begins in the abdomen at the cranial end of the cisterna chyli at the lower border of twelth thoracic vertebra and ends in the left jugulo subclavian junction in the neck. Its course can be divided into three parts 1. Abdominal 2. Thoracic 3. Cervical. It enters the thorax by passing through the aortic opening under the median arcuate ligament. At the aortic opening descending thoracic aorta is to the left and the azygos vein to the right. During its further course through the posterior mediastinum it goes under the right pleural sac. Here right pleural recess may interven in between the duct and the oesophagus. In company with the azygos vein and descending thoracic aorta it passes behind the oesophagus. Due to the shift of the azygos vein to right and descending thoracic aorta to left, the thoracic duct remains behind the oesophagus all alone. It travels upto the level of the fifth thoracic vertebra, crosses the midline and follows the left border of the oesophagus. During this course it is sandwitched between the left border of oesophagus and the mediastinal surface of the left pleura and the lung. Arch of aorta crosses the thoracic duct at the level of the fourth thoracic vertebra. At the root of the neck thoracic duct turns to the left at

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Valves:

Tributaries in the Neck:

the level of the transverse process of the seventh cervical vertebra and passes between the carotid system infront and the vertebral system behind. Carotid system consists of left common carotid artery, left internal jugular vein and the left vagus nerve. The vertebral system consists of vertebral artery, vertebral vein, sympathetic chain and branches of thyro-cervical trunk. Before termination it lies in front left scalenus anterior muscle, crosses the first part of the left subclavian artery and ends in the left jugulo subclavian junction. It has beaded appearance due to the presence of number of valves. A pair of valve is placed at the termination of the duct which prevents regurgitation of blood in the thoracic duct. After death blood enters the terminal part of the thoracic duct due to non-functioning bicuspid valve at the termination. Tributaries in the abdomen : 1. Bilateral descending thoracic trunk from lower sixth spaces of both sides which pass through the aortic opening and join the thoracic duct in the abdomen. 2. Bilateral ascending lumbar lymph nodes from lateral aortic nodes pass through the pleura and join the thoracic duct. 3. Upper five-sixth intercostal spaces of the left side drain into the thoracic duct. 4. Mediastinal trunk recives lymphatics from liver, diaphragm, pericardium, heart and the oesophagus. 5. Left subclavian lymph trunk. 6. Left internal jugular lymph trunk. 7. Left broncho mediastinal lymph trunk. Left jugular and the left subclavian trunks open in it. They may open independently in the internal jugular and the left sub-clavian veins respetively. More commonly the left broncho-mediastinal trunk opens independently at the jugulo-subclavian junction or it may join the thoracic duct. In brief the thoracic duct drains the whole of the body below the the diaphgragm and left half of the body above the diaphragm. Posterior relations: 1. Vertebral bodies and anterior longitudinal ligament. 2. Hemiazygos veins-terminal part. 3. Right posterior intercostal arteries. Anterior relations in thorax: 1. Diaphragm - liver. 2. Oesophagus 3. Left recurrent laryngeal nerve as it lies in front of the left border of the oesophagus. 4. Pericardium, 5. Left atrium, 6. Coronary sinus. 7. Arch of aorta. 8. Root of the left subclavian artery. The duct is narrow in the mid-thoracic region and wider at the commencement and the termination.

Thoracic Duct and Veins in the Thorax Structure of Thoracic Duct:

Development (Figures 182 and 183):

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It consists of three layers : 1. External, 2. Middle, and 3. The internal. They are respectively known as externa, media and interna. In addition to these, it has a well defined sub-endothelial layer. Middle layer has connective tissue fibres arranged along the long axis of the duct. During embryonic life, two longitudinal lymphatic channels are present by the sides of the primitive vertebral column. They are inter-connected by three transverse channels. The transverse channel at the level of the fifth thoracic vertebra gets enlarged. The right upper and the left lower limbs of the original longitudinal channel disappear. The right lower, anastomose at the 5th thoracic and the left upper channels forms the thoracic duct. It explains the peculiar course of the thoracic duct in the thorax. PIease keep letter H before your eyes and put X (cross marks) on its left lower and right upper limbs of the H and get the course of the thoracic duct crossing the midline at the level of fifth thoracic vertebra.

Figure 182 Showing development of thoracic duct

Figure 183 Posterior relations of thoracic duct (viewed from above)

Interesting Story of the Thoracic Duct:

Thoracic duct with two friends, the blue on the right (e.g. azygos vein) and the red on the left (e.g. Aorta), start journey at the twelfth thoracic vertrbra and pass under the wel-come arch of median arcuate ligament. Very soon they are in the darkness under the oesophagus. Blue and red friends are shaken with fear and run away to the right and left from the undersurface of the oesophagus deserting the thoracic duct. Right blue friend makes friendship with the root of the right lung and the left one makes friendship with the root of the left lung. Poor thoracic duct remains behind the oesophagus all alone. It gathers courage and manages to travel upto fifth thoracic vertebra where it comes out of the oesophagus, and follows its left border. Arch of aorta with the left subclavian artery gets irritated due to the new friendship of the thoracic duct with the left border of the oesophagus. At the level of fourth thoracic vertebra, the

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Clinical (Figures 184 to 186):

Azygos Vein (Azygos Means Unpaired):

Figure 184 Showing azygos and hemiazygos veins and tributaries

Figure 185 Showing azygos vein and right pleural recess (viewed from above)

arch sits on the thoracic duct with the left subclavian artery. Poor thoracic duct tolerates this insult and goes to the left side of the neck. It turns laterally at the tip of the transverse process of the seventh cervical vertebra and passes between the vertebral and carotid systems, vertebral being behind and the carotid infront. I would like to say that “aorta asks its two friends at the root of the neck to catch the duct in the neck and throttle”. The thoracic duct is totally tired and takes rest on the left scleneous anterior muscle which is used as the bed prevertebral fascia as the sheet and the left phrenic nerve as the pillow. The thoracic duct takes a revange from the arterial opponents by crosssing the first part of the left subclavian artery just before its death. Injury to the duct, itself, is due to accidental injury during operations of sympathectomy, or invasion by the surrounding tumours. In such cases rupture of the duct leads to leakage of the chyle in the thorax (chylothorax). Microfilarial infection causes obstruction of smaller tributaries and may lead to formation of the filarial hydrocel and the thickness of scrotum, or the non-pitting type oedema of the lower limbs. (Elephantiasis—Elephant Leg). It is formed by the union of the right ascending lumbar and the right subcostal veins. It may arise from the posterior aspect of the inferior vena cava at the level of the renal veins. In the abdomen, it is covered by the right crus of the diaphragm, to the left lie the thoracic duct and the abdominal aorta. It passes through the aortic opening alongwith the thoracic duct and the aorta. After passing under the diaphragm it enters the posterior mediastinum. Here it lies under cover of the right border of the oesophagus, it comes out and arches over the root of the right lung crossing the right border of

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Figure 186 Showing azygos vein in abdomen and some of its relations in the thorax

Tributaries:

Valves: Development: Inferior Hemiazygos Vein (Figure 187): Tributaries:

Communication: Superior Hemiazygos Vein:

Figure 187 Showing mediastinum seen from the right. Note how the azygos vein escapes under the eosophagus arches over the root of the right lung crossing the trachea and the right vagus on its way to the superior vena cava

the oesophagus, trachea and the right vagus nerve. It opens into the superior vena cava at the level of right second costal cartilage. During its ascent in the posterior mediastinum the vein lies on the bodies of the thoracic vertebrae, anterior longitudinal ligament and the right posterior intercostal arteries. Right lung, pleura and the right greater splanchinic nerve are on the right. Following are the tributaries of the azygos vein. 1. Right superior intercostal vein: It is formed by union of the veins of second, third and the fourth intercostal spaces and drains into the azygos vein. 2. Superior and inferior hemiazygos veins. 3. Oesophageal, mediastinal, pericardial and the right bronchial veins. 4. Right ascending lumbar and subcostal veins. Only the tributaries of azygos veins are provided with the valves. Terminal portion of azygos vein is derived from the right posterior cardinal vein. It drains the lower left intercostal spaces, crosses the midline to the right at the level of the eighth thoracic vertebra. During this course it passes under the descending thoracic aorta and the oesophagus. 1. Posterior intercostal veins of the lower three left intercostal spaces. 2. Conjoint trunk formed by the union of left ascending lumbar and subcostal veins. 3. Oesophageal and mediastinal veins. Inferior hemiazygos vein is usually in communication with the left renal vein. Superior hemiazygos vein drains the fourth, fifth, sixth and seventh, and eighth intercostal spaces of the left side. Left bronchial veins may join it. Sometimes superior and inferior hemiazygos veins join to form a common trunk which drains into the azygos vein.

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Posterior Intercostal Veins: Right Superior Intercostal Vein:

Superior Vena Cava (Figure 188):

Vein of the first space crosses the neck of the first rib, arches above the pleura and ultimately ends in the respective innominate veins. They may terminate in the vertebral veins. Right superior intercostal vein is a combined trunk draining the second and third intercostal spaces and joins the azygos vein near its termination. The remaining veins of the right intercostal spaces below, drain separately in the azygos vein. The left superior intercostal vein has already been described. In an attempt to join the left bracheo-cephalic vein crosses the aorta, left vagus and itself gets crossed by the left phrenic nerve. Superior vena cava lies in the superior mediastinum sandwiched between the right lung on the right and ascending part of arch of aorta on the left. It is formed at the level of the right first costal cartilage, runs downwards with a slight convexity towards the right (Corresponding to the convexity of the arch) pierces the pericardium at the right second costal cartilage. It gets surrounded by the serous pericardium and ends in the postero-superior aspect of the right atrium at the level of the right third costal cartilage. It is joined by the azygos vein at the level of right second costal cartilage. The superior vena cava is formed by union of right and left brachiocephalic veins at the level of the right first costal cartilage joined by the azygos vein at right second costal cartilage and enter the right atrium at the level of the right third costal cartilage. Aid to memory Superior vena cava is a story of one, two and, three. It formed at the first, joined at the second and ends at the third.

Figure 188 Showing superior vena cava

Relations on the Right Side:

Anterior Relations : 1. Anterior border of right lung and pleura, 2. Small portion of the pericardium, 3. Internal thoracic mammary artery and 4. First and second intercostal spaces. It is interesting to note that all four structures forming the right relations begin from the letter “P”. 1. Phrenic 2. Pleura, 3. Pleural cavity 4. Pulmone (lung), Relations on the left side : 1. Ascending aorta, 2. Proximal part of the brachia-cephalic artery.

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Posterior Relations: They can be divided in upper and the lower parts. Upper Part: Trachea, right vagus oesophagus and the azygos vein are posterior to this part of the superior vena cava. It lies in front of the root of the right lung where the right pulmonary Lower Part: artery forms the most important posterior relation of the superior vena cava. In operation for the tetralogy of Fallot left subclavian artery is anastomosed to the pulmonary artery. 1. Blalock-Taussig : Subclavian artery to the pulmonary artery. 2. Waterston ascending aorta is connected to the right pulmonary artery. 3. Pott’s descending aorta is connected to the left pulmonary artery.

CLINICAL Obstruction of the Superior Vena Cava (Figure 189):

Obstruction of the superior vena cava is mostly due to the lymphomas or bronchogenic carcinoma. The tumor causes compression of the vena cava as it is a thin walled structure. When the obstruction is above the opening of the azygos vein, blood passes through the intercostal veins including the internal thoracic mammary into the azygos vein to the superior vena cava. When the block is below the opening of the azygos vein blood passes into the inferior vena cava through the azygos. Superficial venous channel specially the thoraco epigastric vein opens and enlarge. Lateral pectoral a tributary of the axillary vein forms an anastomotic channel with the superficial epigastric vein a tributory of the long saphenous vein which joins the femoral vein. Blood passes from axillary vein to the femoral vein through this channel. Congenital anomalies of superior vena cava : 1. Left sided superior vena cava 2. Bilateral superior vena cava.

Figure 189 Showing collateral circulation of superior and inferior vena cava they open in vena caval obstructions

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Figure 190 Showing development of superior vena cava

Development (Figure 190): Valves:

Inferior Vena Cava:

Relations:

The left sided superior vena cava commonly opens in the coronary sinus. Superior vena cava develops from the right duct of Cuvier and the part of the right anterior cardinal vein. The right posterior cardinal vein forms the azygos vein. There are no valves for the superior vena cava. However the valve nearest to the heart is situated in the internal jugular vein. It is due to the above fact, the portion of the internal jugular vein below the level of the valve is selected for recording the venous pulse pressure transmitted from the heart. It passes through the opening in the central tendon of the diaphragm, at the level of the eighth throacic vertebra and immediately enters the pericardium. Inside the fibrous pericardium it is covered by the serous pericardium on all sides except posteriorly. It opens into the lower and posterior part of right atrium. It is provided with a valve. (Valve of the Inferior vena cava) Anterior relations : 1. Diaphragm 2. Pericardium. Right relations - [3 (P)] 1. Phrenic nerve. 2. Pleura. 3. Pleural cavity. 4. Pulmone. Posterior relation : 1. Vertebral column. 2. Anterior longitudinal ligament.

Left Relations:

To the left of the thoracic part of the inferior vena cava lies the the oesphagus. Following are the tributaties of the left brachio-cephalic vein (Figure 191) A. Thoracic duct at the commencement of the vein (jugulo-subclavian junction). B. Vertebral veins, internal mammary vein, inferior thyroid veins and the left superior intercostal vein. Thymus in case of the children and its remanants in case of adults lie in front of left brachio-cephalic vein.

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Figure 191 Showing left brachiocephalic vein and its tributaries

Right Brachiocephalic Vein:

Right brachio-cephalic vein is formed behind the right sternoclavicular joint by union of the right internal jugular and the right subclavian veins. At the lower border of the first costal cartilage it unites with the left brachio-cephalic vein and forms the superior vena cava. Course of the right brachio-cephalic vein is almost vertical and it is related to the right phrenic nerve and the pleura on the right side.

DEVELOPMENT OF THE VEINS OF THE SUPERIOR MEDIASTINUM Left Brachiocephalic Vein (Figure 192):

Left brachio-cephalic vein develops from the connecting channel between the two anterior cardinal veins. In case of the children this vein is situated slightly above the suprasternal notch (care should be taken to protect vessel during the lower tracheotomy).

Figure 192 Showing development of veins of thorax

Right Brachiocephalic Vein:

Embryologically it represents the part of the right anterior cardinal vein.

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THYMUS

Thymus at Birth (Figure 193):

The thymus is situated in the superior and anterior mediastinum. Usually it is connected with the thyroid gland by means of the fibrous cord. (Thyro-thymic ligament). Although it is described as having two lobes. In reality, it is not so. As its origin is bilateral from the two parts, which are loosely connected by the connective tissue. On the other hand thyroid gland is truely the bilobed structure, as its two lobes are connected by an isthmus, which is the part of the gland itself. Its weight is about 30 gm. However it is not fully developed at this stage. Situation: It is situated partly in the neck and partly in the thorax.

Figure 193 Showing thymus

Shape:

The thymus is pyramidal and its apex is directed towards thyroid gland. Thyro-thymic ligament, connects the apex of thymus to the lower part of the left lobe of the thyroid gland. Cancer of thyroid may spread to the mediastinum through the Iymphatics running along the thyrothymic ligament. Capsule: It has the fibrous capsule.

RELATIONS Anterior:

Manubrium sternum, lungs, pleurae, sternohyoid and sternothyroid muscles. Posterior Relations: The trachea, oesophagus, arch of aorta, left branchio-cephalic vein and the fibrous pericardium. Thymus in Adults: After puberty regression of this gland leads to the atrophy and hardly few remanants are seen in the fatty tissue. Histology: It presents lobulated appearance on cross section. Each lobule is made of two parts, the cortex and the medulla. Medulla is studded with Iymphocyte like cells known as thymocytes. Most important and prominent feature of the medulla is, the presence of the “Hassal’s corpuscles”. This microscopic peculiarity of the gland helps us in distinguishing it from other lymphoid structures. Thymoma is the

Thymus

Blood Supply:

Venous Drainage (Figure 194):

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commonest tumor of the thymus arising form the epithelial cells of the Hassal’s corpuscles. 1. During development, while in the neck it gets its blood supply from the inferior thyroid arteries. 2. As it comes to the mediastinum, it is supplied by the smaller branches from the internal thoracic mammary arteries. Blood from the gland is drained into the internal thoracic mammary veins and the left brachio-cephalic vein.

Figure 194 Development of thymus

Lymphatic Drainage: Most of the lymph vessels from the gland directly enter the veins. Development: It is endoderm in origin. It developes from the ventral diverticulum of the third pharyngeal pouch. Medulla is derived from the endoderm and the cortex from the mesoderm. As it descends into the mediastinum, it drags the inferior parathyroid downwards (Thymus three - 3rd pouch). Function of It has been shown that the thymus plays an important part in Thymus: immunology. It is site for production of imunologically competent cell. Removal of thymus, helps in acceptance of the grafts. Enlargement of the thymus compresses the trachea and can cause thymic asthma. Thymus is like a postgraduate Institute where immunologically incompetent lymphocytes are admitted, acquire immunological competence and are sent out in the field. Transmission of nerve impulse at neuro-muscular junction is prevented Myasthenia by interfering with the activity of acetylcholine. Patient develops Gravis: muscular weakness and ptosis of the upper lid. Thymus in Old It gets replaced by the fat, however Hassal’s Corpuscles can still be Age: identifed.

CLINICAL Thymoma:

Di George Syndrome:

It is mostly the benign tumour of the thymus which causes extreme degree of muscular weakness known as myasthenia gravis. The muscular weakness gets corrected after the removal of the tumor. Myasthenia gravis is regarded as an autoimmune disorder in which the proteins which help in binding of the acetylcholine to motor end plates are destroyed by the antibodies seen in the myasthenia gravis. In this syndrome there is non-development of the third and the fourth pharyngeal pouches leading to hypoplasia of the thymus and parathyroids. Due to thymic hypoplasia, T cell deficiency occurs which brings down the cellular immunity. The individual is susceptible to infections and invariably succumbs. Absence of parathyroids leads to hypocalemia and tetany.

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Nezelop’s Syndrome: Venous Plexus around the Vertebrae:

The Nezelop’s syndrome is due to non-development of third pharyngeal pouch resulting in abscence of the thymus and the inferior parathyroids. Superior parathyroids being present there is no hypocalemia or tetany. 1. Anterior external plexus 2. Posterior external plexus 3. Internal plexus 4. Intervertebral vein 5. Ascending lumbar veins. They drain venous blood from pelvis and are responsible for secondary at distant places like spine and brain without passing through the lungs and heart. In late months of pregnancy enlarged uterus pressure on the inferior vena cava in supine position. However, vertebrae venous plexus provide an alternate channel. In case of its poor performance woman suffers from supine hypotension which is known as vena caval syndrome.

SYMPATHETIC CHAIN Figure 195 Thoracic sympathetic chain (schematic)

Portion of the sympathetic chain lying in the thorax is known as thoracic part of the sympathetic chain. As it runs downwards, it lies on the necks of the ribs. Lower down the chains lie infront of the vertebrae. Normally it presents twelve ganglia. However due to the fusion of the first thoracic, with the inferior cervical ganglion the stellate ganglion, is formed. This reduces the total number of the thoracic ganglia to the eleven (Figure 195). In the spinal cord the sympathetic grey column occupies the intermediate position between the ventral and the dorsal horns. This is known as lateral grey column. Sympathetic fibers leave the spinal cord along with the anterior primary ramus of the spinal nerve. After reaching the spinal nerve it sends the white ramus to the sympathetic ganglion. These fibers are medulated. Sympathetic fibers after its entry in the sympathetic ganglia synapse and the post ganglionic non-medulated fibers join the spinal nerve (intercostal nerve). This root is known as grey ramus. Thereafter the sympathetic fibers are distributed to the body along the spinal nerves. Pre-ganglionic sympathetic fibers coming from the lateral grey column of the spinal cord has three alternatives 1. Synapse in the ganglion 2. Pass through the ganglion without synapse and go to the next peripheral ganglion. 3. Either ascend or descend in the sympathetic chain for synapse with the higher or lower sympathetic ganglion. Each ganglion gets the white ramus from the intercostal nerve and gives the grey ramus to the respective spinal nerve. (ganglion gives grey). The sympathetic chain leaves the thorax by passing under the medial

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Nerve of Kuntz:

Clinical:

Branches: 1. Grey and white rami. 2. From upper 5 ganglia to the aorta. 3. From 2, 3, 5 to posterior pulmonary plexus. 4. From 2, 3, 4 and 5 to deep cardiac plexus. 5. From 5 to 12 or 11, branches to the organs i.e. visceral branches in the abdomen. There are three splanchnic nerves, they are as under: 1. Greater splanchnic : arises from 5-9 thoracic ganglia and ends in the coelic ganglion and the aortico-renal ganglion. 2. Lesser splanchnic arises from 9-10 and ends in the aortico-renal ganglion. 3. Lowest or least splanchnic arises from the 12th and joins the renal plexus and is also known as renal nerve. Splanchnic nerves pass through the diaphragm after piercing the crus of the diaphragm to enter the abdomen. It is a branch of the second spinal nerve carrying sympathetic fibres from the second thoracic ganglion to the first spinal nerve and finally to the branchial plexus which distributes fibres to the upper limb. Collection of chromafin cells are associated with the thoracic sympathetic chain. Their significance is not known. Sympathectomy is done for following conditions – 1. Raynaud’s disease. 2. Essential Hypertension. 3. Angina pectoris. 4. Causalgia. 5. Painful stump. 6. And the Burger’s disease where the lumbar sympathectomy is done. The lumbar sympathectomy helps in three ways. a. Increases the blood supply of the skin. b. Helps in healing of the ulcer. c. Reduces the pain and delays the amputation. Note: Burger’s disease is known as thrombo angitis obliterance (There is inflammation of the arteries and the veins leading to thrombosis resulting in gangrine.

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INTERVERTEBRAL JOINTS Joint between Vertebral Bodies (Figure 196):

Two adjacent vertebral bodies are connected by means of the intervertebral disc.

Figure 196 Showing joint between vertebral bodies

Anterior and posterior longitudinal ligaments are placed respectively on the anterior and the posterior aspects of the bodies of the vertebra which help in keeping the vertebral bodies together. Intervertebral disc is made of two components. Outer one is known as annulous fibrosus and the inner one as nucleus pulposus. Nucleus pulposus plays an important part in weight bearing due to its water content, hence it is considered to the ball bearing of the vertebral column. In old age it gets desiccated, which reduces its weight bearing capacity of the spine. Figure 197 Showing joints between vertebral arches

1. Functions of intervertebral disc (Figure 196): a. Connects—two bones, b. Forms—secondary cartilage joint, c. Adds—to the length, d. Helps—in forming curvatures, e. Allows—Movements, f. Transmits—weight. 2. Joints between vertebral arches : Two adjoining articular processes are joined together by means of the synovial joints. 3. Synovial joints: There is well defined capsule having lining of the synovial membrane from inside. Apart from the fibrous capsule, it has good support from the supraspinous, interspinous, intertransverse ligaments and the ligamenta flava (Figure 198). 4. Costo-vertebral joints: They are present in two separate groups – i. Joint between the head of the rib and the vertebral body, ii. Joint between tubercle of the rib and the transverse process. They are synovial type. The upper joint surfaces are concavoconvex and

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Figure 198 Showing axis of movement (rotation of rib)

Radiate Ligament:

Costo-transverse Ligaments:

Figure 199 Showing costo-vertebral joints

Figure 200 Showing articulation of the head of the rib with the body of the thoracic vertebra

the lower ones are plane. In the lower, only gliding type of movements take place, while in upper, the rotatory movements of the rib occur along the long axis of its neck of the rib. This helps in respiratory movements of chest wall. Radiate ligament extends from the head of the rib to the vertebral bodies. From the head of the rib, it goes to vertebra above, vertebra below and the intervertebral disc. They are three in number namely the lateral, inferior and the superior. 1. Lateral costo-transverse ligament: It is attached to the non-articular part of the tubercle of the rib and the tip of the transverse process of the vertebra. 2. Inferior costo-transverse ligament: It is attached to the posterior surface of the neck of the rib and the transverse process of the corresponding vertebra. 3. Superior costo-transverse ligament (Figure 199): It is attached to the upper border of the neck of the rib below and the lower border of the transverse process of the immediately higher vertebra. It presents two

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laminae anterior and the posterior. Anterior lamina joins the internal intercostal membrane and the post fuses with the external intercostal muscle. Note (Figures 200 to 202): Joints between two vertebral bodies through intervertebral disc, is known as secondary cartilaginous joint. They are in the middle of the body and allow movements and are permanent. Figure 201 Showing sagittal section through lumbar region. Its shows the position of the intervertebral disc and the spinal nerve

Figure 202 Showing costo-vertebral joint

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THE PERINEUM Introduction:

Bony Pelvic Outlet (Figure 203):

Figure 203 Showing pelvic outlet

Perineum includes the lower part of the trunk which lies between two thighs transversely and extends from the symphysis pubis to the tip of the coccyx vertically. It is diamond shaped and is bounded by the symphysis pubis and inferior pubic ligament anteriorly. Its posterior limit is the tip of the coccyx, antero-laterally it is bounded by the conjoint rami of the pubis and the ischium. Lateral limit is formed by the ischial tuberosities. Its posterolateral limit is formed by the sacro-tuberous ligaments. The region is divided into an anterior and posterior triangles by an imaginary line drawn from the anterior part of the ischial tuberosites. Anterior triangle is known as the urogenital triangle while the posterior is known as the anal triangle.

Anal Triangle

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ANAL TRIANGLE Figure 204 Showing divisions of perineum

Figure 205 Showing triangles of the perineum

Its anterior limit is formed by the free posterior margin of the perineal membrane. Postero-laterally it is bounded by the ischial tuberosities and the sacrotuberous ligaments. Anal canal with external sphincter along with the ischio-rectal fossae are the important contents. Anal triangle can be described as a triangle having its base anteriorly and the apex posteriorly. Contents : 1. Anal canal with its sphincters. 2. Ischio-rectal fossae on either side of the anal canal.

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ISCHIO-RECTAL FOSSA Shape:

It is situated in between obturator internus muscle laterally and the levator ani, anal canal and its sphincter medially (Figures 206 and 206A). It is wedge shaped having its base directed postero-inferiorly and the apex anterosuperiorly. Its apex corresponds to the meeting of the medial and the lateral walls at an acute angle.

BOUNDARIES Lateral Wall (Figure 206):

It is formed by the obturator internus and the fascia covering it (Obturator fascia).

Figure 206 Showing coronal section of ischio-rectal fossa and anal canal

Figure 206A Showing ischiorectal fossa

Medial Wall (Figure 207): Anterior: Posterior: Fascia Lunata (Figure 207):

The medial wall is formed by the levator ani and the anal canal with sphincters. The ischio-rectal fossa is related to the posterior margin of the perineal membrane. It is bounded by the sacro-tuberous ligament and the gluteus maximus muscle. Arrangement of the deep fascia of the fossa is peculiar. It is the deep fascia which lies deep to the superficial fascia at the base of the ischio-

Ischio-Rectal Fossa

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Figure 207 Showing fascia lunata and suprategmental space

Pudendal Canal (Pundendagenitalia) (Figures 208 to 209):

Figure 208 Showing pudendal canal and contents

Figure 209 Showing course of internal pudendal artery and pudendal nerve in the pudendal canal

rectal fossa. Due to the greater amount of fat in the superficial fascia, the deep fascia is pushed upwards forming the main content of the fossa. To start with, from the medial wall it covers levator ani, arches at the apex of the ischio-rectal fossa and jumps to the lateral wall to cover the obturator internus muscle. Fascia in relation with the medial wall is known as the anal fascia and one in relation with the lateral wall is the obturator fascia. There exists well marked space devoid of fat between the apex of the fossa and the tegmental fascia (Fascia at the apex). The space is called the suprategmental space. It is formed by the obturator fascia laterally and the fascia lunata medially. In between the two facial layers a well developed fascial canal is formed. It is known as the pudendal canal (Alcock’s canal). Before we concentrate on the contents of the canal, it will be proper to examine, study and understand the course of the pudendal vessels. Pudendal vessels and the nerve escape from the greater sciatic foramen and enter the lesser. They come to lie on the medial aspect of the ischium and enter the pudendal canal.

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Figure 210 Showing distribution of the pudendal nerve in female

Pudendal Nerve (S2, S3, S4) (Figure 210):

Perineal Nerve:

Muscular Branches:

Dorsal Nerve of the Penis:

Internal Pudendal Artery:

Branches:

In the posterior part of the canal it lies above the internal pudendal artery and soon divides into the dorsal nerve of the penis, which runs above the artery and the perineal nerve, which runs below the artery. During its further course dorsal nerve passes above the perineal membrane and the perineal nerve passes below the membrane. Before dividing into two branches, the pudendal nerve gives the inferior haemorrhoidal nerve. The inferior haemorrhoidal nerve pierces the wall of the pudendal canal and runs from the lateral to the medial wall of the fossa to supply the anal sphincters. (External sphincter, levator ani, mucous membrane of the lower part of the anal canal and the skin around the external opening of the anal canal). It establishes connections with the perineal branch of the posterior cutaneus nerve of the thigh and the scrotal nerves. It runs below the internal pudendal nerve and gives scrotal or labital and muscular branches. The scrotal nerves supply the skin of the scrotum and the labial branches supply the labium majus. Following muscles are supplied by these branches: 1. Superficial transverse perinei muscle. 2. Bulbo-spongiosus. 3. Ischio-cavernosus. 4. Sphincter urethrae. 5. Deep transverse perinei. Dorsal nerve of the penis is the branch of the pudendal nerve which passes deep to the perineal membrane in the deep perineal pouch. It reaches the dorsum of the penis alongwith the dorsal artery of the penis and ends in the glans. Internal pudendal artery the smaller of the branch of the two terminal branches and the anterior division of the internal iliac artery comes out of the greater sciatic formen and enters the lesser. It crosses the dorsum at the tip of the spine of the ischium and enters the pudendal canal on the medial aspect of the ischium and the obturator internus 4 cm above the ischial tuberosity. Dorsal nerve of the penis lies above and the perineal branch below. During its further course it passes into the deep perneal pouch and divides into two terminal branches, the dorsal and the deep arteries of the penis. Inferior haemorroidal artery: It takes origin from the internal pudendal artery in the pudendal canal.

Ischio-Rectal Fossa

Perineal Branch of the Fourth Sacral Nerve:

Inferior Rectal Vein: Clinical:

Figure 211 Showing hiatus of Schwalbe

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It supplies: a. The gluteus maximus. b. The anal canal. It establishes connections with the superior and middle rectal arteries. c. Perineal, artery of the bulb, urethral and two terminal the deep and the dorsal artery of the penis. It enters the fossa at its posterior end and supplies the skin and the external sphincters. Contents of the ischio-rectal fossa : 1. Fat, 2. Inferior haemorrhoidal nerve and its branches, and 3. Inferior rectal artery. This establishes communication between superior and middle rectal veins in the submucosa of anal canal and drains into the internal pudendal vein. 1. Ischio-rectal abscess: The most important content of the ischio-rectal fossa is the fatty tissue. The fatty pads lie on either side of the anal canal. Immediately after the exit of the faecal mass from anal canal due to elastic recoil the anal canal gets closed. 2. As fatty tissue has poor blood supply, it forms the favourite site for the infection (Ischio-rectal abscess). 3. Ischio-rectal abscess is one of the most painful conditions. Reasons being as under: a. Fatty tissue is loculated in small compartments made of fibrous septa. b. Fibrous septae are richly supplied with nerves. With the onset of the infection pus starts collecting in the fibrous compartments. As the quantity of the pus increases, it exerts pressure on the surrounding fibrous septae causing severe pain. Abscess is drained by giving cruciate incision over the base of the fossa. If the pus is not drained earlier, the abscess may open into the anal canal or rectum. This leads to the formation of ano-rectal fistula. 4. Hiatus of Schwalbe (Figure 211): Sometimes there exists a gap between the obturator fascia below and the tendinous origin of the levator ani muscle above. The supra-tegmental space connects the ischiorectal space with pelvic cavity.

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ANAL CANAL Anal Canal:

Subcutaneous Part (Figures 212 and 213):

Superficial Part:

Figure 212 Showing parts of sphincter ani externus and its three parts

Figure 213 Showing parts of sphincter ani externus

Anal orifice lies 4 cm below and in front of the tip of the coccyx. Skin around it is pigmented, corrugated and shows presence of hair only in the males, after the puberty. It is related to the perineal body anteriorly, anococcygeal body (anococcygeal ligament) and the tip of the coccyx posteriorly and the ischio-rectal fossae laterally. Length of the anal canal is about 3.5 cm and is placed almost at the right angle to the lower end of the rectum. It is surrounded by the sphincter ani externus muscle which keeps it closed. Anal canal will be considered in detail at the appropriate time. However, it is worth mentioning the sphincter ani externus muscle. Internal sphincter surrounds the upper 3/4th of the anal canal and ends at the white line. The external sphincter on the other hand surrounds the whole of the anal canal. Sphincter ani externus muscle is organised into three different parts. 1. The subcutaneous, 2. The superficial, and 3. The deep. The subcutaneous part lies below the lower border of the internal sphincter and the superficial part of the external sphincter. It covers the lower border of the internal sphincter and the superficial part of the external sphincter by virtue of the horizontal position. It has no bony origin. Contractions of this group causes corrugation of skin around the anal orifice. The superficial part is elliptical in shape and lies above the subcutaneous part, and external to the internal sphincter. It is the only part which arises from the bone. It takes origin from the tip of the coccyx, surrounds the lower part of the internal sphincter and gets inserted into the perineal body.

Anal Canal Deep Part:

Nerve Supply:

Ano-coccygeal Body:

Lymphatic Drainage of the Region:

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The deep part encircles the upper part of the internal sphincter. It is to be remembered that this set of fibres are fused with those of the puborectalis part of the levator ani muscle. The external sphincter of the anus is supplied by the inferior rectal branch of the pudendal nerve (S2, S3). In addition to it, the perineal branch of fourth sacral nerve also innervates the muscle. Whole of the external sphincter is under control of the will (Voluntary). It is the fibro-muscular body which intervenes between the anal canal and the tip of the coccyx. It is also known as the ano-coccygeal ligament. The elements of muscular tissue comes from the levator ani and the external sphincter. The fibro-muscular body helps in supporting the rectum and the anal canal. Lymph vessels of the lower 1/2 of the anal canal and the skin around it go to the superficial inguinal group of lymph nodes (Medial group).

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UROGENITAL TRIANGLE The urogenital triangle is anteriorly bounded by the symphysis pubis and the inferior pubic ligament, antero-laterally by the conjoint rami of the pubis and the ischium. Posteriorly it is limited by an imaginary line connecting the ischial tuberosities. Skin of this region presents the median fibrous raphae running from the perineal body to the under surface of the scrotum and the the penis. Attachment of the membranous layer of the superficial fascia (Fascia of Colles) (Figures 214 to 216 and 219): Attachment of the membranous layer needs careful study, since it is of importance in determining the course of the extravasated urine. It is attached to the conjoint rami of pubis and ischium antero-laterally and Figure 214 Showing perineal membrane, perineal body, anal canal and anococcygeal body

Figure 215 Showing attachment of membranous layer of superficial fascia (fascia of Colles)

Figure 216 Showing course of urine in the event of rupture of the bulb of urethra (sagittal section)

Urogenital Triangle 503

Clinical Importance of the Fascia of Colles:

Perineal Membrane (Figures 217 and 218):

Figure 217 Showing perineal membrane

Figure 218 Showing opening in the perineal membrane

to the free border of the perineal membrane posteriorly. Anteriorly it is continuous with the similar layer in the abdominal wall known as the fascia of Scarpa. In the males, it covers the scrotum and forms the tubular sheath for the penis. In case of the injury to the bulb of the urethra extravasation of urine occurs in the superficial perineal pouch. It goes posteriorly till it reaches the posterior limit where it is held-up by the line of attachment of the fascia of Colles to the free posterior margin of the perineal membrane. It cannot spread laterally beyond the conjoint rami of the ischium and pubis, due to the attachment to the rami. It passes above and in front to occupy the region of the scrotum and the penis. Once the superficial perineal pouch is filled to the capacity, urine escapes in the anterior abdominal wall between the Scarpa’s fascia and the aponeurosis of the external oblique muscle. Its downward journey is prevented by the line of attachment of the fascia of Scarpa to the fascia lata of the thigh below the inguinal ligament horizontally (Holden’s line). Poorly developed septum fails to separate the two halves of the superficial perineal pouch allowing the urine to go across. The perineal membrane is the triangular fibrous membrane which divides the region in the superficial and the deep perineal pouches. It is the fibrous membrane filling the gap between the pubic arches. At the sides it is attached to the conjoint rami of the pubic and the ischium. Posteriorly it is fused with the fascia on the deep transverse perineal muscle closing the deep perineal pouch posteriorly. Anteriorly it does not reach the pubis but presents the free thickened border which is fused with the fascia on the sphincter urethrae. This thickened anterior border of the membrane is known as the transverse ligament of the perineum.

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Relation of the Membrane:

Openings in the membrane (Figure 218):

The gap between the symphysis pubis and the transverse ligament gives passage to the deep dorsal vein of the penis. Posteriorly, mid-point of the posterior border of the perineal membrane is fused with the perineal body. 1. Above – It is related to: - Membranous part of urethra. - Bulbo-urethral glands. - Sphincter urethrae muscle. - Internal pundendal artery and its branches namely the deep artery and the dorsal artery of the penis. - Dorsal nerve of penis. - Deep transverse perineal muscles. 2. Below - related to: - Bulb of the urethra and muscle bulbo-spongiosus. - Crura-ischio-cavernosus. - Duct of the bulbo-urethral gland. - Scrotal or labial vessels and nerve. - Superficial transverse perini muscle. - Perineal nerve. 1. Opening in the median line for the urethra – 2.5 cm. below symphysis pubis. 2. Opening for the ducts of bulbo-urethral glands on either side of the opening of urethra. 3. Opening for the artery of the bulb. 4. Internal pudendal artery or openings for its two terminal branches the deep and the dorsal artery. 5. Opening for the dorsal nerve of penis – pierces laterally under cover of the crus. Superficial pouch is studied in male and the female (Figures 219 to 221) Superficial perineal pouch in male

Superficial perineal pouch in female

Each half is separated by the incomplete septum.

It is divided in the middle, by the vagina.

Contents: Male

Contents: Female

1. Crura of the penis

1.

Crura of the clitoris

2. Well developed ischio-cavernosus muscle

2.

Poorly developed ischio-cavernosus muscle

3. Bulb of the penis

3.

Bulb of the vestibuli

4. Bulbo-spongiosus muscle arising from 4. the median fibrous raphae

Bulbo-spongiosus muscles- each half of it covers the bulbus of the vestibuli and are separated except anteriorly and posteriorly at the attachments

5. Contains only the ducts of the bulbourethral glands (Glands itself lie in deep pouch)

Greater vestibular glands with its ducts lie in the supeficial pouch. It is comparable to bulbo-urethral gland in male

5.

6. Superficial transverse perineal muscle 6.

Superficial transverse perineal muscle

7. Scrotal nerves and vessels

7.

Labial nerves and vessels

8. Transverse perineal artery- branch of the scrotal artery

8.

Transverse perineal artery branch of the labial artery Contd...

Urogenital Triangle 505 Contd... Superficial perineal pouch in male

Superficial perineal pouch in female

9. Perineal branch of the posterior 9. cutaneous nerve of the thigh, it is placed in front of the ischial tuberosity 10. Body of the penis

Perineal branch of posterior cutaneous nerve of the thigh

10. Body of the clitoris

11. Body of the penis is traversed urethra 11. Body of the clitoris is not traversed by urethra 12. Perineal membrane is well developed 12. Perineal membrane is not well developed and is made weaker by the passage of vagina (It is bisected)

Figure 219 Showing extravasation of urine following injury to the bulb of urethra in the superficial perineal pouch

Figure 220 Showing coronal section through perineal membrane to show deep and superficial perineal pouches

Figure 221 Showing superficial perineal pouch in male

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Superficial Perineal Pouch in Male:

Cutaneous Nerves:

Bulbo-spongiosus:

Action: Nerve Supply: Ischio-cavernosus: Nerve Supply: Superficial Transverse Perineal Muscle: Nerve Supply: Action:

As already mentioned it is the space bounded by the fascia of Colles below and the perineal membrane above. This space is closed by the attachment of fascia of Colles to the conjont rami of pubis and the ischum laterally and the free margin of the perineal membrane posteriorly. In the rupture of the bulb of urethra, urine collects in the superficial perineal pouch and can go to other side as the septum between the two halves of the superficial perineal pouch is incomplete. Following cutaneous nerves supply the area of skin of the urogenital triangle scrotum and the penis. 1. Ilio-inguinal nerve (L 1) : It supplies the skin of the uppermost part of the scrotum. 2. Perineal branch of the posterior cutaneous nerve of the thigh. It supplies the skin of the perineum and posterior part of the scrotum. 3. Scrotal nerves: They arise from the perineal branch of the pudendal nerve and supply the skin of scrotum and perineum. 4. Dorsal nerve of penis: It supplies the skin of the penis. As regards, the superficial fascia of the scrotal region mention of the dartos muscle must be made. Dartos muscle replaces the superficial fascia of the scrotal region and is responsible for giving corrugated appearance to the scrotum. It is an involuntary muscle. (It is comparable with the platysma of the neck). Contents of superficial perineal pouch (in male): It contains: i. Bulb and the spongy part of the urethra. ii. Crura of the penis. iii. Bulbo-spongiosus muscle. iv. Ischio-cavernosus muscles. v. Superficial transverses perini muscles. 5. Vessels and nerves: Scrotal, transverse perineal artery, artery of the bulb, terminal branches of internal pudendal artery namely deep and the dorsal arteries of the penis. 6. Portion of the duct of bulbo-urethral glands. The muscle arises from the median fibrous raphe and the perineal body. Its fibres are arranged into 3 sets. Out of these the posterior set of fibres cover the bulb of urethra and ultimately get inserted into the perineal membrane. During contractions of this particular set, bulb of urethra is compressed against the perineal membrane. Middle set of fibres cover the posterior part of the corpus spongiosus and get inserted on the dorsum of it. Contraction of this set of fibres cause compression of the spongy part of urethra. The anterior set of fibres are like a letter V. They divert, cover the corpora cavernosa and wind the corpora cavernosa, reach the dorsal aspect of the penis for the insertion. Posterior and intermediate sets of fibres evacuate the last drop of urine and the semen. It may help in erection of the penis. It is supplied by perineal branch of the pudendal nerve. It arises from the conjoint ramus of the ischium and pubis. It covers the crus and ultimately gets inserted into its anteriorly. It is supplied by perineal branch of pudendal. This muscle arises from the ramus of the ischium a little in front of ischial tuberosity, runs medially for its insertion into the perineal body. It is supplied by perineal branches of pudendal. Contraction of two transverse superficial perineal muscles, helps in fixing the perineal body.

Urogenital Triangle 507

Roots of the penis: Crus of the Penis:

Fixation of perineal body is important for the effective contraction of external sphincter and bulbo-spongiosus. It is made of the bulb and the crura. The bulb is the broad posterior end of corpus spongiosum. Urethra enters the bulb from its dorsal aspect after piercing the perineal membrane. Posterior end of the corpus cavernosum of the penis is narrow. It is known as the crus. It is closely related and attached to the pubic arch. Dorsal nerve of the penis and internal pundendal artery or its two terminal branches come out of the deep pouch under the crus. Erectile tissue, cavernous spaces and the venous blood form the structure of the bulb and crura.

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DEEP PERINEAL POUCH (Figures 222 and 223) Figure 222 Showing deep perineal pouch

Figure 223 Showing sphincter urethrae muscle

This space lies above the perineal membrane.

Membranous Part of Urethra:

Sphincter Urethrae:

Contents: It contain 1. Membranous part of the urethra. 2. Bulbo-urethral glands. 3. Sphincter urethrae muscle. 4. Deep transverse perineal muscle. 5. Internal pudendal artery, artery of the bulb.(Sometimes two terminal branches of the internal pudendal namely deep and the dorsal artery of the penis). 6. Dorsal nerve of the penis. Membranous part of the urethra is the shortest part of urethra having length of about 1.25 cm. Prostatic urethra ends at the upper limit of deep pouch where the membranous part begins. The membranous urethra ends at the lower aspect of the perineal membrane and is followed by the spongy part. Membranous part of urethra is surrounded by sphincter urethrae muscle in the deep perineal pouch. Sphincter urethrae has two distinct parts, circular and the transverse. Circular fibres surround the membranous part of the urethra. The

Deep Perineal Pouch

Course of Urethra in the Male:

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transverse part arises from the pubis and the perineal membrane runs transversely towards the urethra. Some of the fibres pass in front and behind the urethra. They are continuous above with muscular part of prostate and have connections with the muscle fibres of urethra. Course of urethra is shaped like “~” in the male. Its proximal part (Prostatic and membranous) is directed downwards and anteriorly, while the spongy part inclines upwards, anteriorly, it finally turns downwards. Knowledge of of the course and direction of the urethra is essential for passing the urethral staff or metal catheter.

Figure 224 Showing contents of superficial perineal pouch

CLINICAL Rupture of the Bulb of Urethra:

Bulbo-urethral Glands: Internal Pudendal Artery:

Branches of the Internal Pudendal Artery in the Urogenital Triangle (Figures 225 and 226):

The rupture occurs due to fall on a man-hole cover of a drainage or on a beam astrice. Urine collects in the superficial preineal pouch and does not go laterally and posteriorly as already explained. It goes to the upper part of the thigh but does not descend down below the Holden’s line (line of attachment of Scarpa’s fascia to that of deep fascia of the thigh. It goes to lower abdomen, the scrotum and the penis. They are situated postero-lateral to the membranous part of the urethra in the deep pouch. Ducts of the glands pass through the perineal membrane and open into the spongy part of urethra. As it enters the deep perineal pouch above the perineal membrane, runs forwards and divides into two terminal branches in the deep and the dorsal artery of the penis or after piercing the perineal membrane. This division lies under the crus. During its course in the deep pouch, dorsal nerve of the penis lies on its lateral side. We have already seen that the internal pudendal artery gives inferior rectal branch in the pudendal canal which lies along the lateral wall of the ischio-rectal fossa. Scrotal (labial) arteries arise from the internal pundeandal artery and the transverse perineal branch arises from the scrotal or labial. 1. Artery of the bulb: Pierces the perineal membrane and enters the bulb. 2. Dorsal artery of the penis: It runs on the dorsum of the penis with the deep dorsal vein. Dorsal nerve of the penis is lateral to the artery. These structures are placed between the two layers of the suspensory ligament of the penis. 3. Deep artery of the penis: It passes into the substance of the crus and forms helicine arteries of the corpora cavernosa.

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Figure 225 Showing deep branches of internal pudendal artery in male

Figure 226 Showing course of internal pudendal artery and its branches

Deep Transverse Perineal Muscle: Nerve Supply: Dorsal Merve of the Penis:

It arises from the junction of the pubic and the ischial rami. Both meet in the centre and fuses with the sphincter urethrae anteriorly. Perineal nerve. It arises from the pudendal nerve in the pudendal canal and runs forwards above the perineal membrane to enter the deep perineal pouch. In the canal it lies above the internal pudendal artery, but as it runs forwards in the deep perineal pouch it comes to lie on the lateral side of the internal pudendal and dorsal artery of the penis. It supplies the corpora cavernosa and the skin of the penis.

Penis

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PENIS It is the male copulatory organ made of erectile tissues. The attached portion is known as root and the free portion is known as the body. Root of the penis is made of three masses of erectile tissue. They are named as two crura and one bulb of the penis. Each crus is attached to the ramus of the pubis on either side. Each is covered by muscle known as ischiocavernosus. The bulb of the penis has an attachment to the undersurface of the perineal membrane. Bulb lies in the centre and is covered by the bulbo-spongiosus muscle. Urethra passes through the bulbus, corpus spongiosum and the glans (Figures 227 to 229). Figure 227 Showing erectile bodies of penis. Glans penis is removed

Figure 228 Male urethra

Figure 229 Transverse section of human penis

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Body of the Penis (Figures 230 and 231):

Figure 230 Showing amputated (cut) penis with structures under the fascia of Buck. Window is made in the fascia to show underlying structures

Body of the penis is free and flaccid. It hangs down from the symphysis pubis. It has dorsal and ventral surfaces. In the middle of the dorsal surface lies the superficial dorsal vein of the penis. Skin of the body of the penis is thin and freely movable. The superficial fascia of the penis is devoid of fat. Tip of the penis presents as the glans penis which becomes visible when the foreskin is pulled back. In the centre of the lower part of the glans is a vertical slit like opening known as external-urethral meatus. It is the narrowest part of the male urethra. Proximally glans has a raised soft circularly placed margin known as the corona. Corona is followed by the neck of penis posteriorly. Corona has sebaceous glands which produce white coloured material known as smegma. Skin covering the glans is known as the prepuce or foreskin. It can be retracted to and fro. The prepuse is free from the glans except lower down where fold of skin is attached to the under surface of the glans. Space between the prepute and the glans is known as preputal sac. Smegma collects in the preputial space. Smegma is carcinogenic and may cause cancer of the penis. Circumcision (Cutting and removal of the part prepuse) grants 100% immunity from the cancer of penis. Preputial skin when retracted fully shows two zones, pigmented posterior and non pigmented anteriorly. Pigmented zone forms the outer part of the prepuse while the non pigmented part forms the inner part of the preputial skin. It is the non pigmented part of the skin which is in contact with the glans. Frenulum of the penis is a triangular fold of skin attached to the glans below the urethral meatus. Its base is attached to the skin of the prepuse. Prepuse and the frenulum are supplied by the dorsal artery of the penis, the branch of internal pudendal artery. It is formed by three erectile masses. Two corpora cavernosa lying side by side, providing a grooved under surface for the corpus spongiosum. Body of the penis is covered with skin which is freely mobile. Two crura are attached to the pubic rami posteriorly, while the bulb of the penis which lies in the centre is attached to the under surface of the perineal membrane. Corpora cavernosa are the continuations of the crura and the corpus spongiosum is the continuation of the bulb of penis. All the three are enclosed in the tough fibrous sheath known as tunica albuginea. Tunica albuginea has two layers superficial and the deep. Superficial layer contains longitudinal fibers. The deep layer has circular fibers and cover the corpus spongiosum separately. Corpora cavernosa end anteriorly as the narrow anterior ends, which are covered by the glans penis like a cap cover. Glans penis has a dilated roof anteriorly known as navicular fossa. Superficial fascia of the penis is continuous with the

Penis

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Figure 231 Showing sagittal section of penis. Note glans cover the corpus cavernosum in front

Ligaments of the Penis:

Blood Supply of the Penis:

Venous Drainage: Deep Dorsal Vein of Penis:

Nerve Supply:

Lymphatic Drainage: Erection of Penis:

fascia of Colles of the perineum. Fascia of Colles is the continuation of the fascia of Scarpa of the abdomen. Deep fascia of the penis is known as fascia of Buck. It encloses all the three components of the penis. Corpora cavernosa contains vascular spaces which are filled with blood to the capacity during erection. Corpus spongiosum is traversed by the urethra. Superficial to the fascia of Buck lies the superificial vein of the penis in the mid-line. Under the fascia the Buck lie the deep dorsal vein of the penis in the mid-line flanked by the deep dorsal arteries of the penis and the dorsal nerves, on either side. Deep dorsal vein of the penis occupies the midline position on the dorsum of the penis followed by the artery and the nerve from the medial to the lateral (VAN). 1. Fundiform ligament: It runs from linea alba to the body of the penis and splits to enclose the penis. 2. Suspensory ligament of penis: It is under the fundiform ligament. It runs from the symphysis pubis to cover the body of the penis. Branches of the internal pudendal artery supply the penis. As under: 1. Deep artery of the penis: It enters the corpora cavernosa of the penis and divides into spiral branches known as helicine arteries. 2. Dorsal artery of the penis: It runs on the dorsum of the penis under the fascia of Buck. It supplies the glans, terminal part of the corpus spongiosum, prepuse and the frenulum. 3. Artery of the bulb: It supplies the bulb of the penis and the posterior part of the corpora spongiosa. Note: Superficial external pudendal arteries the branches of the femoral artery also supply the skin and the fascia of the penis. Superficial dorsal vein of the penis divides into two and drains in the superficial, external pudendal veins. Lies under the fascia of Buck, passes through a gap between the perineal membrane and the inferior pubic ligament. It drains into the prostatic venous plexus which itself is connected to the vesical venous plexus. The vesical venous plexus joins the internal iliac veins. Sensory nerve supply of the penis is from the dorsal nerve of the penis and the ilio-inguinal nerve. Autonomic nerve supply of the penis is from the pelvic plexus through the prostatic plexus. Sympathetic nerves are vaso-constrictors and the parasympathetic vaso-dilators. Autonomic nerve supply comes through the branches of the pudendal nerve. Highest cutaneous sensitivity exists over the glans and the frenulum. It is mainly in superficial inguinal nodes. However, lymphatics from the glans penis drain into the gland of Cloquet, which is in the femoral canal. Erection of the penis is a vascular phenomenon. The vascular spaces of the corpora cavernosa get filled with blood giving turgidity to the penis.

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Mechanisum of Erection of Penis:

Clinical:

Due to accumulation of blood within the fascia of Buck, the size of the penis increases. Due to increased pressure within the penis the veins are compressed. As the penis becomes turgid it points dorsally raising its dorsal surface towards the abdomen. As a result the deep dorsal vein of penis is compressed against the symphysis pubis. Compression of the deep dorsal vein of penis prevents venous return from the penis helping to maintain the erection. No wonder that there are divices such as belts, which help in keeping the penis in the dorsally erected position, blocking the deep dorsal vein of penis and prolonging the time of erection. It is due to parasympathetic stimulation from S2, to S4 to erectile tissue in the carpora cavernosa. Stimulation of these nerves increases blood flow into the corpora cavernosa. This makes the penis turgid and erect. Sympathetic stimulation from T12, L1 may help in erection. Sacral 2 to sacral 4 are under control of limbic system and the hypothalamus which receives sexual stimuli through visual, auditory, tactile, olfactory and gustatory sensations. Psychogenic (Mental) stimuli also play a part. (W.C. Casey, I.S.65:2:1980 page 175). 1. Penile erection: Vascular obstruction can cause inability of the erection of penis. This can possibly be corrected by connecting the inferior epigastric artery to the dorsal artery of the penis. (C.W.Casey, I.S. 65:2:1980). 2. Meatal stenosis: A pinhole meatus can lead to back pressure effects affecting the kidneys and the ureters. The pinhole meatus is incised lower down and the skin and the mucous membrane of the urethra are sutured. 3. Congenital stricture: Congenital stricture of urethra is treated by urethrotomy by an optical instrument. Even simple dilatation of the stricture may help. 4. Congenital valves of the urethra: Catheter goes in however urine does not come out. The condition is treated by transurethral resection of the valves. 5. Fracture of penis: It occurs during full erection of penis accompanied by vigorous and forcefull sexual intercourse. Clinically there is pain, swelling as a result of bleeding. Haematoma should be drained and bleeding vessels be ligated. 6. Carcinoma of the penis: Circumcision soon after the birth grants almost 100% immunity against the carcinoma of the penis. Carcinoma of the penis starts as leukoplakia (Leuco-mean white, i.e. white patch) resulting in pipilloma. Carcinoma of the penis is squamous cell carcinoma involving the penis partially. It can be treated by partial amputation of the penis. The superficial inguinal lymph nodes are not touched for three weaks as there enlargement could be inflammatory. Involvement of the complete shaft of the penis with bilateral involvement of superficial inguinal lymph nodes is treated by radical amputation of penis with bilateral block dissection of the superficial inguinal nodes. 7. Paget’s disease of the penis: There is a non healing raw area over the glance penis associated with the underlying carcinoma. 8. Peyronie’s disease: It presents as a thick fibrous plaque, often calcified, present in the tunics of the penis. It gives pain during erection. It causes deformity in the erect penis. Normally it resolves itself.

Penis

Development of Penis (Figure 232):

515

9. Buschke Lowenstein tumour: Its peculiarity is it is locally destructive and invasive however it does not metastasise to the nearby lymph nodes. 10. Balanoposthitis: Inflammation of the prepuce is known as posthitis and the inflammation glans is known as balanitis. As both the conditions are associated together. It is known as Balanoposthitis. 11. Paraphimosis and phimosis: Retracted tight foreskin refuses to return. It may cause venous and lymphatic obstruction of the glans. It can be treated by circumcision. In emergency dorsal sliting of the prepuce under local anesthetic is enough. 12. Persistant Priapism: In this condition penis remains erect and gives pain. In priapism glans penis and the corpus spongiosum are not involved. The condition occurs in blood diseases like sickle cell disease or leukaemia. It may occure due to the malignancy of the corpora cavernosa. It must be remembered that the priapism rarely occurs in the spinal cord disease. It is treated by aspiration of blood from the body of the penis. In resistant cases corpus spongiosum is anastomosed to one of the corpus cavernosum. Penis develops from the genital tubercle. Part of the cloacal membrane in relation to the urogenital sinus breaks. This orifice becomes continuous with the groove on the under surface of the elongated genital tubercle (Phallus). Lips of the groove unite from caudo-cranially and thus the original orifice is shifted to the tip. Earlier the skin covering of the glans is connected to it. Due to the desquamation of the epithelium, skin around the glans gets separated from it except at the small area underneath. This connection forms the frenulum and the rest of the free skin forms the prepuce (Hood or cover). The skin of prepuce can move before backwards freely. Congenital or acquired narrow opening of the prepuce is known as phimosis, which is treated by circumsation (cutting of the preputal skin).

Figure 232 Development of penis

Development of Male Urethra:

Scrotum (Figure 233):

Male urethra develops from three sources: (1) Proximal part upto the colliculus seminalis develops from urogenital sinus, (2) Middle part: from colliculus seminalis to terminal part-develops from urethral plate, and (3) Terminal part - develops from ectoderm. Female urethra corresponds to the proximal part in the male. It develops from urogenital sinus. It is a bag of skin devoid of fat meant for the testis and epidydamis and partially for the spermatic cord. Skin is covered with course hair and has sebaceous glands. A median partition of dartos muscle, separates two scrotal sacs from each other. Corresponding to the septum a slightly raised median fibrous raphae is seen, on the surface which runs from the under surface of the penis to the anus. It indicates the bilateral origin of the structure. The scrotal swellings in the males are the representatives of the labia majora of the female.

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Figure 233 Showing layers of scrotum

Scrotal skin gets corrugated due to contractions of the dartos muscle in the cold. While in the hot wether it hangs down. This phenomenon is attributed to the role of dartos in maintaining the temperature apt for spermatogenesis. They are arranged as under from outside in: Layers of the 1. Skin Scrotum: 2. Dartos 3. External spermatic fascia 4. Cremasteric fascia 5. Internal spermatic fascia Blood Supply of It is supplied by the Scrotum: 1. Superior external pudendal 2. Deep external pudendal 3. Scrotal branch of internal pudendal 4. Cremaster branch of the inferior epigastric. Nerve Supply: Ilio inguinal and the genital branch of the genitor femoral supply the anterior 1/3rd of the scrotal skin while the posterior 2/3rd is supplied by scrotal branches of pudendal nerve and the perineal branch of posterior cutaneous nerve of thigh. Dartos is supplied by genital branch of genito-femoral. Lymphatic Drainage: Lymphatic goes to the superficial inguinal nodes. Clinical (Figure234): 1. Absent or non-development of the scrotal sac is indicative of undescended testis. 2. Scrotal skin is enormously thickned in filariasis. It is due to obstruction of the pelvic lymphatics by Wuchereria bancropti. 3. Hydrocele: It is an abnormal collection of serous fluid in the tunica vaginalis testis. It is of four varities i. Vaginal ii. Infantile iii. Congenital iv. Hydrocele of the cord. Figure 234 Showing types of hydrocele

Penis

Acquired:

Complications of Hydrocele: Treatment:

Lord’s Operation:

517

The peritoneal covering of the testis is known as tunica vaginalis testis. It is formed by processus vaginalis which accompanies the testis through the anterior abdominal wall. It has two layers, parietal and the visceral. Posterior border of the testis is divide of the peritoneal covering. It is directly related to the seminal vesical and the vas difference. The space between the visceral and the perital layer of the tunica vaginalis contains small amount of fluid which prevent friction between the two layers. It is of two types: 1. Primary 2. Secondary 1. Primary: Primary hydrocele occurs due to excessive production of fluid which does not get absorbed. Transillumination is positive and many times the testis is palpable. Primary hydrocele is tense. Testicular tumours in young persons may present as an acute hydrocele. Hydrocele may be associated with the inguinal hernia. 2. Secondary: It is due to acute or chronic epididymo-orchitis. However, torsion and the tumour of the testis are not uncommon. Treatment of the underlying cause is the treatment. Note: Bilateral hydrocel is suggestive of the ascitis or tuberculous ascitis. 1. Haematocele: blood in the tunica vaginalis testis. 2. Clotted hydrocele: hydrocel with blood clot. Excision and eversion of the sac (Jaboulay’s operation). In this the scrotum is incised and the sac is freed. Fluid is drained and the redundant part of the sac is excised. Eversion of the sac is done which prevents reformation of the hydrocele. Lord’s operation is done when the sac is thin, and is not required to be excised. The thin sac of the tunica vaginalis is plicated with the nonabsorbable sutures which forms and collar around the testis. 1. Being dependant loose and lax scrotal oedema appears in cardiac failure, renal failure and severe anaemia and hypoproteinemia. Indirect inguinal hernia and the testicular tumours are the causes of the scrotal swellings. 2. How to differentiate between the scrotal swelling due to the indirect inguinal hernia from other causes. Palpate the scrotal swelling with the finger and the thumb above. If you can reach above the swelling, the swelling is purely scrotal one. In indirect inguinal hernia you can not reach above scrotal swelling due to the hernial sac and its cotents. 3. As the scrotal skin is studied with sebaceous gland it presents multiple sebaceous cysts. Treatment of the sebaceous cysts of the scrotum is difficult as they are multiple. 4. Carcinoma of scrotum : It is commonly seen in tar and oil workers. It is squamous cell carcinoma. Superficial group of inguinal lymph nodes are involved. It is mistake to look for superficial group of lymph nodes in the malignant tumours of the testis as the lymphatic drainage of the testis is in the aortic group of lymph nodes. 5. Fournier’s gangrene: This is also known as idiopathic oedema of the scrotal skin. It is due to the blockage of the scrotal vessels, with superadded infection. Gangrene appears very rapidly and the whole scrotal contents is shade off like a dead cover exposing the testis and the other scrotal contents. 6. Developmental anomalies:

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Classification of Hypospadias:

i. Absence of penis ii. Epispadias: In this condition the urethral opening is situated on the dorsum of the penis. This condition is commonly associated with ectopia vesicae iii. Hypospadias: Urethral opening is placed on the surface of the penis. It is due to defective or incomplete union of the urethral folds. Fusion of the urethral fold is caudo-cranially. In case of Hypospadias the inferior aspect of the prepuse is poorely developed while the dorsal one is well developed. They are glandular, coronal, penile and perineal. Glandular type of hypospadias does not require treatment, while in the perineal scrotum is split and the urethra is open.

Female Perineum

519

FEMALE PERINEUM Superficial Perineal Pouch:

Crus of the Clitoris (Figure 235): Bulb of the Vestibule:

Following are the contents of the superficial perineal pouch in female. 1. Crus of the clitoris, 2. Bulb of the vestibule 3. Superficial perineal muscles, 4. Greater vestibular glands, 5. Urethra and 6. Vagina. Although smaller in form, structurally it is similar to the crus of the penis in the males and is covered by the muscle known as ischio-cavernosus. It is present on either side of the vaginal walls. Both are united in front of the urethra by means of the bulbar commissure. If veiwed with care it is seen that the commissure is continuous with the glans of the clitoris anteriorly and therefore, seen similar to the corpus spongiosum penis of the male.

Figure 235 Showing female perineum

Superficial Perineal Muscles: Bulbospongiosus:

Greater Vestibular Glands (Bartholin’s Gland):

It is situated on either side of the lateral vaginal wall, covering the bulb of the vestibule. It arises from the perineal body behind, and gets attached to the body of the clitoris in front. Functionally it works like a sphincter of the vagina. It compresses the dorsal vein and helps in erection. 1. Superficial transverse perineal muscle: It is a thin muscular strip similar to that of the superficial transverse perini muscles of the male. 2. Ischio cavernosus: It runs from the ischial tuberocity posteriorly to the sides and the under surface of the clitoris. It covers the crus of the clitoris prevents the venous return and helps in erection. 3. Deep transverse perineal muscle: It runs from the ischial tuberosity to the perineal body. It helps in fixation of the perineal body during the contractions of the perineal muscles. 4. Sphinctor urethrae: It has two parts the superior and the inferior. Inferior part arises from the transverse perineal surround the urethra as a sling and goes back to the transverse perineal ligament superior part forms the sphincter of the female urethra. They are situated on either side and are related to the posterior ends of the bulbs of the vestibule. Their ducts open into the vagina near the region of the labium minus. (Morphologically they are similar to the bulbo-urethral glands of the males). Blockage of the duct leads the formation of the cyst (Bartholin’s).

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Female Urethra:

Clinical:

External Genitalia of the Female (Figure 236):

Figure 236 Female external genitalia

Female urethra is 3.75 cm long and has a diameter of 6 mm. The direction of the female urethra is downwards and forwards. It opens into the vestibule about 2.5 cm below the clitoris (Clitoris is not traversed by the urethra, that is how, it differs from the penis). The urethra begins at the internal urethral meatus in the middle of the symphysis pubis and passes through the perineal membrane and gets embedded in the anterior vaginal wall. It opens in the vestibule of vagina 2.5 cms below the clitoris. Posterior wall of the female urethra has the urethral crest. Mucus glands and the lacunae open in the urethra. They are known as paraurethral glands of Skene. They are drained by paraurethral ducts which open into the vestibule on either side of the external urethral meatus. They represent the prostate gland of the male. Different shapes of the urethra seen in transverse sections at the beginning, middle and at the end do not have clinical application. Female urethra is dilatable and presents no problem while passing a cystoscope. 1. Urethritis: Inflammation of urethra is known as urethritis. Short urethra is the cause of cystitis which is common in women. 2. Indian female urethritis: It is fairly common in women due to repeated child births. Peri-urethral glands get infected and cause narrowing of the urethra. Patient presents with a complaint of incomplete sense of evacuation after each micturation. This leads to frequency and dysuria. The condition can be treated by dilatation under local anesthesia on 3 to 5 occasions. I have seen and treated cases of Indian female urethritis on multiple occasions. 3. Traumatic rupture of femal urethra: It is mostly due to the prolonged obstructed labour in which urethra is crushed between the pubis and the head of the foetus. It may lead to formation of urethrovaginal-fistula. Soft, raised part of the skin (due to pad of fat) lying in front of the symphyseal region is known as mons pubis. Pudendal cleft is limited by the thick skin folds (with underlying fat) known as labia majora. They are connected by the anterior and the posterior commissures, are in front and behind. Lying within the boundaries of the labia majora are two folds the labia minora. They are connected posteriorly by means of frenulum labiorum. In front the frenulum it splits into two smaller bands, superior and the inferior. Inferior band gets attached to the under surface of the glans of the clitoris and forms the frenulum, while the upper one unites with the fellow of the opposite side above the clitoris, and form the prepuce of the clitoris. Cavity bounded by the two minora is known

Female Perineum

Lymphatic Drainage:

Bartholin’s Glands:

Bartholin’s Cyst:

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as vestibule of the vagina. Urethral and the vaginal openings open in the vestibule of the vagina, the urethra being anterior and the vagina posterior. Lymphatics from perineum drain into the superficial inguinal group of lymph nodes. Enlargement of this groups of lymph nodes occur in infections of the perini. It is most important to remember that the lymphatic from the terminal part of the anal canal drain into the superficial inguinal group of lymph nodes. They are homlogus to Cowper’s glands in male. They are at the entrance of vagina related to the posterior end of the vertibule of vagina. Duct of the gland has a length of 1.25 to 2 cm. It opens between the hymen above and labium minus below. Duct is lined by multi-layered columnar cells. Secretion of the gland is mucoid, colourless and has a peculiar odour. It is poured into vulva as a result of sexual excitement which acts as a lubricant during coitus. It is due to blockage of the duct due fibrosis following infection or trauma. It is of a size of hen’s egg and is noticed by woman when it interfers with coitus. It can be excised or marsupialised, e.g. suturing the margins of the cyst wall to the skin.

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ABDOMEN

Surface Landmarks and the Subdivisions:

Abdominal cavity can be called a magic box. Therefore, it is important to study the situation of organs and their relative positions in relation to the anterior abdominal wall. Surface subdivisions have definitely helped the descriptions of the injuries and swellings to the greater extent. These subdivisions should be studied with great interest as they form the basis of the surface anatomy of the abdomen. Whole of the anterior abdominal wall is divided into nine regions. There are surface land-marks which are useful to the medical student during his study and also to the physician or surgeon during practice. Following are the important surface landmarks 1. Subcostal arch: It is formed by the 7th, 8th, 9th and the 10th costal cartilages. Subcostal plane crosses the 3rd lumbar vertebra. 2. Xiphi sternum: An effort to feel for the xiphoid process is a painful act in the living subjects. It lies at the 9th, thoracic vertebra. 3. Linea alba : It is in the midline and is marked by a shallow vertical groove. It is thick (1 cm) above umbilicus and thin below. 4. Umbilicus: It is the most unreliable landmark. Segmental cutaneous innervation of the umbilical region is from 10th thoracic. 5. Pubic crest and tubercle: They are the parts of the pubic bone. The pubic tubercle is felt at the medial end of the inguinal furrow. 6. Linea semilunaris: Lateral border of the rectus abdominis muscle produces a grooved line which crosses the sub-costal arch at the tip of the 9th costal cartilage. The lower border of linea semilunaris reaches the pubic tubercle. At the tip of the 9th costal cartilage lies the fundus of the gall bladder. In cholecystitis (inflammation) of the gall bladder, there is tenderness at the tip of the 9th costal cartilage. (Murphy’s sign) 7. Inguinal ligament. It lies under the inguinal furrow and extends from the anterior superior iliac spine to the pubic tubercle. 8. Anterior superior iliac spine: It lies at the level of the sacral promontory. 9. Iliac crest: It is at the lateral end of the inguinal furrow and corresponds to the level of 4th lumbar vertebra. Iliac tubercle lies 5 cm behind the anterior superior iliac spine. Inter-tubercular line passes through the level of 5th lumbar vertebra, while the line between the iliac crests lies at the 4th lumbar vertebra. 10. Rectus abdominis itself. 11. Mid-inguinal point: It is the midpoint of the line joining the anterior superior iliac spine and the symphysis pubis. (It is not the midpoint of the inguinal ligament. Following planes are commonly used for the divisions of the anterior abdominal wall (Figure 237): 1. Trans-pyloric plane: It is drawn horizontally at the mid-point of the line joining the suprasternal notch and the symphysis. The transpyloric, intertubercular the right and the left vertical planes are marked on the anterior abdominal wall for the purpose of 9 divisions.

Abdomen

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Figure 237 Showing nine subdivisions of the anterior abdominal wall

Division of the Anterior Abdominal Wall:

Trans-pyloric Plane:

2. Intertubercular plane: It is the line joining the two iliac tubercles. It is at the level of the body of the fifth lumbar vertebra. The junction of the caecum and the ascending colon lies at this plane on the right side. 3. Right vertical plane is drawn from the right mid-inguinal point. 4. Left vertical plane is drawn from the left, mid-inguinal point. A. There are three divisions above the trans-pyloric plane, epigastric in the middle laterally flanked by the right and the left hypochndric regions. B. Three divisions are between the transpyloric plane above and the intertubercular plane below. The umbilical region in the middle laterally flanked by the right and the left lumbar regions. C. Below the inter-tubercular line is the hypogastric region in the middle laterally flanked by the right and left iliac fossae. The four quadrants of anterior abdominal wall are marked, by drawing two artificial lines, vertical and the transverse at the level of the umbilical. Clinically it can be used for four quadrant tapping of the abdomen in suspected intraperitoneal bleeding cases. Trans-pyloric plane passes through the pylorus. It is drawn transversely round the trunk at the level of the mid-point of the line between the suprasternal notch and the symphysis pubis. It passes through the 9th costal cartilages and corresponds to the level of the first lumbar vertebra. In the living it can be drawn at a point, hands bredth below the xiphysternum. Following important structures lie in this plane (Figure 238): 1. Fundus of the gall bladder. 2. Pylorus of the stomach. 3. Neck of the pancreas. Once we know that the neck of pancreas is at the level of the first lumbar it is easier for us to imagine and remember that the following structures also must lie at this plane. 4. Formation of portal vein. 5. Origin of the superior mesenteric artery. 6. Hilum of the right kidney. Deep fascia is absent on the anterior abdominal wall, allowing free

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Figure 238 Showing 4 quadrants of anterior abdominal wall. Clinically used for four quadrant tapping in accidental injuries

Skin:

Umbilicus (Figures 239 and 240):

Clinical:

Figure 239 Formation of femoral shealth. Noth fascia transversalis joins inguinal ligament lateral to the femoral vessels (A). On the other hand fascia transversalis and fascia iliac form femoral sheath at the site of femoral vessels (B) Figure 240 Showing superficial fascia of lower abdominal wall and its two layers

distension of the abdomen after the full meal. It must be remembered that the respiration in infants is purely abdominal. Skin of the abdomen has collagen lines in the dermis placed horizontally with a little oblique inclination encircling the trunk (Langer’s lines). Incisions given along the lines heal early with minimum scar. Below the level of the umbilicus the superficial fascia has two layers, namely fatty and the membranous. Fatty layer is known as the fascia of Camphor and the membranous is known as fascia of the Scarpa. Fascia of Scarpa continues in the perineum over the scrotum and the penis as the fascia of Colles. It is a small rounded scar at the embryonic attachment of the umbilical cord. It is placed a little below the mid-point of the line joining the xiphoid and the symphysis. Normally its level corresponds to the disc between the third and the fourth lumbar vertebrae. The level of the umbilicus is not constant, hence it should be taken as the most unreliable landmark. I have seen a case in which an umbilicus had its location hardly two fingures above the symphysis. Umbilicus is not properly and regularly cleaned. It may become the site of sepsis and calculus (Umbilical calculus). In the newborn umbilical cord should be cut with all the aseptic precautions. Failure to do so can result in sepsis, jaundice and even portal pyaemia. Eversion of the umbilicus is as clinical sign of ascites. During foetal life, urachus, 2 umbilical arteries and the left umbilical vein

Abdomen Embryology (Figure 241):

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pass through the opening, in the anterior abdominal wall. In addition to these the vitello-intestinal duct is seen connecting the umbilicus with the gut. Normally this connection is lost. In case of its persistence in the postnatal life leads to the formation of the faecal fistula. When it persists in the form of a fibrous cord, loops of the intestine get twisted around it, causing intestinal obstruction. A part of the vitello-intestinal duct may persist in the form of localised dilatation (Cyst). It may persist as a small stump attached to the intestine with no connection with the umbilicus (Meckel’s diverticulum). Meckel’s diverticulum is situated two feet away from ilieocaecal junction at the antemesenteric border and has a length of two inches (5 cm). It has two types of ectopic tissues namely the gastric and the pancreatic. Meckel’s diverticulum has a peculiar association with the vitella-intestinal. Incidence - 2%

Figure 241 Showing vitello-intestinal duct and allantois

Situation - 2’ feet away from ileo-caecal junction. Length - 2’ Tissues - 2 types (Gastric and Pancreatic). Patent urachus leads to dribbling of urine through the umbilicus. Left umbilical vein gets fibrosed to form the ligamentum teres hepatis. Small veins accompany the ligament to the left branch of the portal vein. They are known as paraumbilical vein. They drain blood from the anterior abdominal wall around the umbilicus to the left branch of the portal vein. In cases of portal obstruction, veins are seen enlarged and radiating from the umbilicus (Caput Medusae) due to the porta-systemic anastomosis at the umbilicus (Figure 243). Umbilical region is supplied by the 10th thoracic segment. Nerve Supply of the Amongst the triad of appendicitis (pain, vomiting and fever). Pain of Umbilical Region (Figure 242): Figure 242 Showing cutaneus innervation of the anterior abdominal wall. Remember T10 umbilicus and L1 groin

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Figure 243 Showing caput medusae

Superficial Fascia:

Cutaneous Nerves:

appendicitis is felt at the umbilicus in the initial stages (referred pain) being visceral. The landmarks of nerve supply of the anterior abdominal wall can be remembered as 10th at the umbilicus and L1 at groin, by the ilio-inguinal and the ilio-hypogastric nerves. This region, corresponds to the area below the line drawn horizontally from the anterior superior iliac spines. Superficial fascia has two layers, the superficial fatty layer of Camper and deep membranous layer, the fascia of Scarpa. The deep layer is devoid of fat and has more of elastic fibres. Well marked collection of the elastic fibres is seen over the lower part of the linea alba which run over the symphysis and meet the suspensory ligament of the penis. In quadrupeds (four footed animals) this band is extensive and has a definite function of suspending and supporting the weight of the viscera. Fatty layer runs over the inguinal ligament and becomes continuous with the superificial fascia of the thigh, while the deep or membranous is firmly fixed to the deep fascia of thigh just below the inguinal ligament. The attachment of fascia of Scarpa to the deep fascia of thigh is straight. It is known as Holden’s line. Fascia of Scarpa continues as the fascia of Colles in the perineum. It is carried over the penis and the scrotum. Upper six intercostal nerves restrict to their spaces. The 7th, 8th and 9th leave their spaces by passing deep to the costal cartilages and enter the anterior abdominal wall. The 10th and the 11th nerves go directly into the anterior abdominal wall. Lower 5 intercostals, subcostal and the first lumbar nerves innervate the anterior abdominal wall. Ilio-hypogastric and ilio-inguinal belong to first lumbar nerve. Ilio-hypogastric pierces the external obliqe muscle an inch (2.5 cm) above the superficial inguinal ring while the ilio-inguinal comes out through the superficial inguinal ring. It innervates the skin of the scrotum or labia majora. Anterior cutaneous branches of the 5 intercostal, and subcostal nerves pierce the anterior wall of the rectus sheath. In addition to this, lateral cutaneous branches of the 3 intercostal nerves come out at the slips of origin of the external oblique muscle. Each divides into an anterior and a posterior divisions. External oblique muscle gets its nerve supply from the anterior divisions. Lateral cutaneous branch of the subcostal is peculiar in a way that it fails to divide into anterior and the posterior divisions. Undivided trunk crosses the iliac crest and takes part in the innervation of the skin of the gluteal region. Lateral cutaneous branch of the ilio-hypogastric nerve supplies the skin of the gluteal region as it crosses the iliac tubercle. Pain of pleural effusion get referred to the upper abdomen creating

Abdomen Clinical:

Arteries (Figure 244):

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diagnostic problem due to phenomenon of referred pain. 1. Abdominal reflex stimulation skin of the abdominal wall leads to contraction of the muscles of abdominal wall. Absence of this reflex indicates damage to the pyramidal tract. 2. Due to rich and profuse blood supply of the anterior abdominal wall the types and sites of surgical incisions are of no practical value. Apart from the small unnamed cutaneous arteries there are other, which deserve attention. Lateral cutaneous nerves are accompanied by the branches of the posterior intercostal arteries, while the anterior cutaneous nerves are accompanied by the branches of the superior and inferior epigastric ateries. In the superficial fascia of the lower part of the anterior abdominal wall are the following branches of the femoral artery. 1. Superficial external pudendal—runs towards the scortum or labium

Figure 244 Showing blood supply of the anterior abdominal wall

Superficial Veins of the Region (Figures 245 and 246): Figure 245 Showing veins of the abdominal wall

majora. 2. Superficial epigastric—goes upto the umbilicus. 3. Superficial circuflex iliac—runs towards the anterior superior iliac spine. Drainage of blood from the area above the umbilicus is by the lateral thoracic and internal thoracic mammary veins. Drainage of blood from the area below the umbilicus goes to the femoral vein (Figures 144 and 145). The upper group finds its way to the superior vena cava and the lower one into the inferior vena cava. Two groups are in free communi-

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Figure 246 Showing lymphatic drainage of anteriorabdominal wall

Lymph Vessels:

cation with each other at the umbilicus and also have connection with portal vein. Therefore, in cases of vena caval obstruction, the veins dilate and gets enlarged as collateral channels. Umbilicus is described as a site of lymphatic watershade. Lymph vessels go in different directions from the umbilicus to both the axillary and the inguinal nodes. Therefore carcinoma of the umbilicus can spread to all the four groups of lymph nodes.

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MUSCLES OF THE ANTERIOR ABDOMINAL WALL

Action on Spine and Trunk:

External Oblique (Figure 247):

Following are the muscles form the anterior abdominal wall: 1. Rectus abdominis and pyramidalis are situated on either side of the linea alba. Pyramidalis lies over the lower part of the rectus abdominis muscle. Both are enclosed within a fascial pocket - the rectus sheath. 2. External oblique, 3. Internal oblique and 4. The transversus abdominis muscles. The above muscles are fleshy only in the lateral part and become aponeurotic medially where they form the rectus sheath. Direction of the fibres of the respective muscle is significant and must be remembered. External oblique is directed downwards, medially and forwards while the internal oblique goes upwards, medially and forwards. In other words their fibres are placed at right angle to each other. Fibres of the transversus abdominis take the horizontal course. The arrangement of the of the muscle fibres, grants strength to the wall. They maintain the intraabdominal pressure. The muscles help in the respiration, defaecation, micturation, parturition and other acts such as coughing and sneezing. Function of the muscles of the anterior abdominal wall apart from the functions mentioned above. Most important function of the anterior abdominal wall musles is the reflex protective contraction to prevent damage to the delicate internal viscera from the blunt external injury to the anterior abdominal wall without pre-anticipation. Rehearsals of fighting scenes for the production of a motion pictures have resulted in fatal injuries needing emergency surgery. It is entirely due to the unawareness of the expecting blow and the relaxed anterior abdominal wall. In ‘seat belt’ syndrome a driver suffers severe injury to the mesentery such as tear and to the small intestine such as rupture. It is due to the unawareness of the driver regarding the impending accident, who continues to drive with relaxed anterior abdominal wall. Morphologically muscles of the anterior abdominal wall were suspensory to support the abdominal viscera in quadrupeds. Due to erect posture the muscles have migrated laterally in order to balance the trunk on the femora. Hence, there action on spine in flexion and the rotation of the trunk are obligatory. They are the balancing ropes of the trunk running in strategic directions. The pyramidalis muscle tenses the linea alba in order to help the anterior abdominal wall muscles to contract effectively. The external oblique muscle originates from the lower eight ribs (there are 8 alphabets in the word external), where it interdigitates with the digitations of the serratus anterior muscle, (which also has 8 alphabets in word serratus and 8 digitations, however there are only twelve ribs hence the two muscles mentioned above have the common site of digitation). Fibres arising from the lower ribs run vertically downwards and get inserted into the anterior 2/3rd of the outer lip of the ventral segment of the iliac crest. Fibres arising from the 5th rib take horizontal course and get inserted into the xiphoid process. The remaining fibres are fleshy above the line joining the anterior superior iliac spine and the

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Figure 247 Showing external oblique muscle of abdomen

Parts of the Inguinal Ligament:

The pectineal Ligament or Ligament of Sir Astley Cooper (Figure 248): Figure 248 Showing parts of inguinal ligament

umbilicus. Below the line muscle becomes aponeurotic and it is known as the aponeurosis of the external oblique muscle of the abdomen. Attachment of this aponeurosis can be traced from the anterior superior iliac spine to the xiphoid process. Lower free inrolled margin of the external oblique aponeurosis is known as the inguinal ligament. It is attached to the anterior superior iliac spine laterally and the pubic tubercle medially. It is attached to the deep fascia of the thigh. By virtue of the inguinal ligament to the deep fascia of the thigh, the lower margin of the inguinal ligament is pulled towards the thigh. Superificial inguinal ring is infact the triangular opening situated in the aponeurosis of the external oblique muscle above and lateral to the pubic tubercle. The opening is limited medially and laterally by the medial and the lateral crurae. Inter crural fibers are above the opening and prevent separation of the crura. At the superficial inguinal ring the aponeurosis gives the thin covering for the spermatic cord, known as the external spermatic fascia. 1. Pectineal part (Lacunar or Gimernat’s ligament). It is situated below the medial end of the inguinal ligament with its apex at the pubic tubercle and the curved base, directed laterally. In erect posture the external surface of the pectineal part faces downwards and the inner surface upwards. 2. Reflected part of the inguinal ligament: It arises from the lateral crus of the superficial inguinal ring and runs upwards and medially behind the superficial inguinal ring. It lies infront of the conjoint tendon and forms part of the posterior wall of the inguinal canal. Its fibres from both the sides cross in the linea alba. Its medial end is attached to the base of the pectineal part of the inguinal ligament and continues laterally along the iliopectineal line (pectin pubis). Lower fibres of the linea alba and the fascia of the pectineus contributes to its strength. During hernioplasty this ligament is used for fixing sutures.

Muscles of the Anterior Abdominal Wall Superficial Inguinal Ring (Figure 249):

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It is triangular in shape and is limited by two crura Base is formed by the lateral part of the pubic crest and its apex is directed superolaterally. Medial crus is attached to the pubic crest and the symphysis pubis, while the lateral is attached into the pubic tubercle and the inguinal ligament. The intercrural fibres keep the crura in approximation. Spermatic cord in case of the male and the round ligament of the uterus in the female come out of the ring. However, a thin, but fairly developed layer known as external spermatic fascia runs along with spermatic cord from the margins of the superficial inguinal ring. The spermatic cord can be pressed against the pubic tubercle.

Figure 249 Showing reflected part of inguinal ligament

Internal Oblique (Figure 250):

As the name indicates, it is internal to the external abdominis muscle. Its fibres are at right angle to the fibers of the external oblique muscle.

Figure 250 Showing superficial inguinal ring

Origin: Insertion (Figure 251):

Figure 251 Showing internal oblique muscle of abdomen and cremaster muscles

Internal oblique muscle arises from the middle of the ventral 2/3rd of the iliac crest and the lateral 1/2nd of the inguinal ligament. Lower fibres fuse with the fibres of the transverse abdominis medially and get attached to the pubic crest and the pectineal line. They form the conjoint tendon. The fibres of the internal oblique muscle arch over the spermatic cord obliquely, so that the lateral part is in front, middle above and the medial (conjoint tendon) lies behind the cord. Majority of the fibres run upwards, medially for insertion into the subcostal arch, xiphoid

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Nerve Supply: Cremaster (Figure 252):

process and the linea alba. However, the posterior fibres ascend vertically from the iliac crest and get attached to the 12th, 11th and 10th ribs. Aponeurosis of the muscle as it reaches the lateral border of the rectus abdominis, divides into the anterior and the posterior lamillae and run in front and behind the rectus abdominis muscle forming the parts of the anterior and the posterior walls of the rectus sheath. Lower 6 intercostal and first lumbar nerves supply the muscle. The muscle originates from the middle of the inguinal ligament and comes out of the superficial inguinal ring. From there onwards, they form the loops of successively greater length and may reach the scrotum. Medial limb of the loops unite to form the tendon, which ascends on the posteromedial aspect of the cord and gets inserted into the tubercle and crest of the pubis. Gaps between the loops are filled with loose areolar tissue, which is known as the the cremasteric fascia (Some authors consider cremaster muscle as the dragged down fibres of the internal oblique muscle.).

Figure 252 Showing cremaster muscle and pyramidalis

Nerve Supply: Action:

It is supplied by genital branch of genito-femoral nerve. Although histologically striated (volunatary) the muscle is not under control of will. Its main job is to pull the testis upwards and bring it nearer the superficial inguinal ring. (Reflex role in preventing herniationby plugging the ring). Action can be summarised as: 1. Hangs the testis 2. Pulls the testis 3. Plugs the superficial inguinal ring and prevents hearniation. 4. Maintains the temperature.

CLINICAL Cremasteric Reflex (Figure 253):

It is the reflex, contractions of the cremasteric muscle followed by the stimulation of the skin of the upper medial part of the thigh. Testis is pulled upwards and the superficial inguinal ring is plugged. Note : Reflex is well developed in children. Absence of cremasteric reflex indicates upper motor neurone lesion above L1. Upper neurone lesion produces spastic type of paralysis without wasting of the muscles.

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Figure 253 Showing path of cremasteric reflex

TRANSVERSUS ABDOMINIS Origin:

Insertion (Figure 254):

Nerve Supply:

Rectus Sheath:

Figure 254 Showing transversus abdominis muscles

It arises from the under surface of the 7 to 12 costal cartilages, interdigitating with the fibres of origin of diaphragm, lumbar fascia, medial lip of the ventral 2/3rd of the iliac crest and lateral 1/3rd of the inguinal ligament. Lower fibres fuse with those of the internal oblique to form the conjoint tendon. Higher fibres get attached to xiphoid process. Rest of the fibers are seen running transversely for the insertion to the linea alba. It is interesting to note that the aponeurosis is narrow above and below but wider in the middle. At times transversus abdominis is connected to the superior ramus of pubis by means of interfoveolar ligament. Lower 6 intercostal and first lumbar nerve supply it. Note : If you buy 1 Kg. of sugar from the grocer’s shop the grocer binds the packet of sugar obliquely and transversely. It is with a purpose of giving strength to the paper packet containing sugar. Rectus sheath is an incomplete fascial pocket for the rectus abdominis, pyramidalis, superior epigastric artery, inferior epigastric artery, intercostal and subcostal nerves. It is formed by the external, internal and the transversus abdominal muscles. Its anterior wall incomplete and the

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Figure 255 Showing rectus sheath

Rectus Sheath in the Upper Onethird: Rectus Sheath in the Middle (Figure 255):

Rectus Sheath in the Lower Onethird (Figures 260 and 261):

posterior wall incomplete above and below. Formation of the rectus sheath can be studied as under (Figures 255, 259): 1. Upper 1/3 2. Middle 1/3 3. Lower 1/3 Anterior wall is formed by an aponeurosis of the external oblique muscle. Posterior wall being deficient, the rectus abdominis muscle lies directly on the costal cartilages. It is complete in the middle. Anterior wall of the sheath is formed by aponeurosis of the external oblique and the anterior lamina of the internal oblique anteriorly while the posterior wall is formed by the posterior lamina of the internal oblique muscle and an aponeurosis of transversus abdominis muscle posteriorly. Anterior wall of the sheath is formed by the aponeurosis of the three muscles, i.e. the external oblique, internal oblique and the transverse abdominis. Posterior wall of the sheath being deficient, the rectus abdominis muscle lies directly on the fascia transversalis.

CONTENTS Rectus Abdominis Muscle: Origin:

Insertions:

Tendinous Intersections:

Nerve Supply:

It is one of the important contents of the rectus sheath. Its origin is from below and insertion above. It has two heads of orign which are tendinous 1. Lateral head arises from the pubic crest. 2. Medial head arises from the symphysis pubis. The fibres are vertically directed upwards to reach the front of the thorax. The muscle is inserted into the cartilages of the 7th, 6th and the 5th. The line of insertion is horizontal. Tendinous intersections of the rectus abdominis muscle are three in number which divide the muscle into smaller four segments. The tendinous intersections are attached to the anterior abdominal wall of the rectus sheath. The rectus abdominis muscle is supplied by the lower 6 or 7 intercostal nerve.

Muscles of the Anterior Abdominal Wall Clinical:

Divarication of Recti (Figure 257):

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Haematoma of the rectus abdominis is due to the blunt injury to the anterior abdominal wall. It injures the inferior epigastric artery at the site of arcuate ligament and leads to fatal haemorrhage. Patient’s life can be saved by ligating the inferior mesenteric artery in emergency surgery. The recti are separated from each other, and the gap between the two can be seen during straining. When relaxed fingers can be passed through the gap inside. This condition is common in old and multiparus women. In children the divarication of recti is commonly seen above the umbilicus. It does not require surgery as there is no possibility of strangulation the gap being wider.

Figure 256 Showing origin of pyramidalis muscle from the body of pubis and the anterior ligament of symphysis

Figure 257 Showing rectus sheath

Pyramidalis (Figure 256):

Lower 5 Intercostal and the Subcostal Nerves: Superior and Inferior Epigastric Arteries:

It arises from the anterior aspect of the symphysis pubis just below the pubic crest and the anterior pubic ligament and gets inserted into the linea alba. It is sandwitched between the rectus abdominis muscle and anterior wall of the rectus sheath. It is triangular in shape and is the tensor of the linea alba. It is the innervated by the subcostal nerve. They pierce the posterior wall of the rectus sheath, run medially behind the rectus abdominis muscle, pierce the anterior wall of the rectus sheaths, and continue as the anterior cutaneous nerves. Superior epigastric artery is one of the two terminal branches of the internal thoracic mammary, the other being the musculophrenic. Inferior epigastric artery is the branch of the external iliac artery.

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Fascia Transversalis:

They run behind the rectus abdominis muscle and anastomose to form the collateral channel between the first part of subclavian, and the external iliac arteries. It is the thin layer of fascia forming the inner lining of the abdomen. It is studied by transverse and ventrical sections. It lies between the transversalis muscle and the extraperitoneal fat. It can be used for the repair of the indirect inguinal hernia. i. Transverse tracing (Figure 258): The layer meets the lateral border of the kidney splits into two layers, namely the anterior and the posterior. Anterior layer runs medially in front of the kidney and goes across the vertebral column to meet the similar layer on the opposite side. The posterior layer fuses with the fascia covering the psoas major muscle and the lumbar vertebra. Fascia transversalis forms the anterior wall of the femoral sheath below the inguinal ligament.

Figure 258 Showing transverse tracing of fascia transversalis (as seen from above)

Deep Crural Arch (Figure 259): Figure 259 Horizontal sections passing through rectus sheath

ii. Vertical tracing : Fascia transversalis lines the anterior abdominal wall and continues to cover the undersurface of the diaphragm. It jumps to the posterior abdominal wall comes to the pelvis where it meets the fascia iliaca and the pelvic fascia. iii. In the inguinal region: Lateral to the femoral vessels fascia transversalis gets attached to the inguinal ligament and ends their. Medially the layer continues downwards in the thigh as the anterior wall of the femoral sheath. The posterior wall of the femoral sheath is formed by fascia iliaca. Medial to femoral vessels two layers get fused. Some fibres from the fascia transversalis lying in front of the femoral vessels run laterally in an arched fashion towards the anterior superior

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Figure 259A Showing neurovascular plane of anterior abdominal wall

Figure 260 Showing horizontal section in middle part of the rectus sheath

Figure 261 Showing schematic sagittal section of rectus sheath. Note passing of inferior epigastric artery through fascia transversalis

Deep Inguinal Ring:

iliac spine. Medial group undertakes a course in an arched manner and disappears behind the rectus abdominis muscle. However, some fibres descend to have an attachment to the pectineal line. These structural components of the deep crural arch limit the medial and the inferior margin of the deep inguinal ring. Identification of the ring is difficult due to continuation of a tube like extension of the fascia along the spermatic cord known as the internal spermatic fascia. Deep inguinal ring is placed 1.25 cm above the mid-inguinal point. Above the ring are the arched fibers of the transversus abdominis muscle. Medially, it is related to inferior epigastric artery. It is larger in size in male due to the size of the spermatic cord.

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Figure 262 Showing horizontal section of inguinal canal. Showing the canal and its anterior and posterior walls (schematic). Note the formation of conjoint tendon

Inguinal Canal (Figure 262):

Floor:

Roof: Anterior Wall:

Posterior Wall (Figure 263):

Figure 263 Showing inguinal triangle and structures around seen from behind

Inguinal canal is a potential inter-muscular canal situated in the inguinal region above the medial half of the inguinal ligament. It is directed downwards medially and forwards between the deep and the superficial inguinal rings. Inguinal canal is 3.75 cm (1.5”) in length. Deep inguinal ring is situated 1.25 cm (½”) above the mid-inguinal point in the fascia transversalis. Superficial inguinal ring is situated in an aponeurosis of the external oblique muscle of the abdomen above and lateral to the pubic tubercle. The floor is formed by the abdominal surface of the pectineal part of the inguinal ligament medially, and the lateral part is formed by the grooved surface of the inguinal ligament. As the spermatic cord comes out at the medial end of the canal, it lies on the pectineal part of the inguinal ligament and can be pressed against the pubic tubercle. The operating surgeon can feel pulsations of the inferior epigastric artery, medial to the neck of the sac. Indirect inguinal hernia is lateral to the internal epigastric artery while the direct inguinal is medial to inferior epigastric artery. The roof is formed by the arched lower fibres of the internal oblique muscle or the conjoint tendon. Aponeurosis of the external oblique muscle of the abdomen forms the entire anterior wall. However, the lateral part of the wall is strengthened by the internal oblique muscle. Fascia transversalis forms the entire posterior wall. However, the conjoint tendon and the reflected part of the inguinal ligament, support the wall medially. The inferior epigastric artery lies medial to the deep inguinal ring. It is an important relation of the posterior wall. The lower part of the triangular area bounded by the inguinal ligament below, inferior epigastric artery laterally and the lateral border of the rectus abdominis muscle medially, form the posterior wall of the canal. This triangular area is known as the “inguinal triangle” or “Hasselbach’s triangle”. It is the site for the direct inguinal hernia.

Muscles of the Anterior Abdominal Wall

Arteries of the Anterior Abdominal Wall (Figure 254):

Inferior Epigastric Artery (Figure 255):

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Contents of the inguinal canal in the male and female are as under. In the male: Spermatic cord with contents of the spermatic cord as under i. Vas deferens ii. Artery of the vas – branch of inferior vasical artery iii. Testicular artery iv. Cremastric artery v. Pampiniform plexus vi. Ilio-inguinal nerve vii. Genital branch of genitor-femoral viii. Lymphatics ix. Remnant of processus vaginalis. In the female Round ligament of uterus, artery of round ligament the branch of inferior epigastric artery. Ileo-inguinal nerve Genital branch of genito-femoral nerve Mechanism of the inguinal canal Due to erect posture abdominal contents come down and put pressure on the lower part of the anterior abdominal wall and the pelvic floor. Following factors try to helps the walls of the inguinal canal to resist the pressure. A. Obliquity of the inguinal canal B. Strengthening Superficial ring is supported by the conjoint tendon and the reflected bay of the inguinal ligament, while the deep ring is supported by the fleshy fibers of the internal oblique muscle of the abdomen. C. Arrangement of internal oblique muscle of the abdomen Internal oblique muscle of the abdomen is anterior, above and posterior to the canal and is arranged like an arch across the inguinal canal. Contraction of the fibers of the internal oblique muscle of the abdomen reduces the gap as it acts like the shutter of a camera. D. Plugging action of the cremaster muscle Contraction of the cremaster plugs the superficial inguinal ring from below. E. Greater omentum the policeman of the abdomen plugs the deep ring from above. F. Medial and lateral crura of the superficial inguinal ring are prevented from separation and are held together by the intercrural fibers. G. Abdominal pressure from inside presses the posterior wall against the anterior wall and helps in obliteration of the canal, due to their overlapping positions. They are as under: 1. The deep circumflex iliac 2. Inferior epigastric 3. Superior epigastric 4. Musculo-phrenic 5. Posterior intercostal 6. Subcostal 7. Lumbar arteries. It takes origin from the external iliac artery proximal to the inguinal ligament in the abdominal cavity and pierces the fascia transversalis to enter the rectus sheath. It goes upwards and medially to meet the lateral border of the rectus abdominis. Before its entry into the rectus sheath it has to cross the arcuate line (lenea semicircularis) from the front. Arcuate line is formed by the lower margin of the posterior wall of the rectus

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Clinical Aspect of the Inferior Epigastric Artery:

Differential Diagnosis:

Abnormal Obturator Artery (Figure 264):

sheath. The arcuate line being sharp and curved like a sickle can cause injury to the inferior epigastric artery. Inferior epigastric artery originate near the internal inguinal ring and is related to its medial margin, where the vas deferens or the round ligament of the uterus hooks from the lateral side. During its further course it lies behind the rectus abdominis muscle and anastamoses with the superior epigastric artery. It gives the artery of the cremaster in male and the artery of the round ligament of the uterus in female. Cremasteric branch in the male follows the spermatic cord and gives branches to the cremaster and anastomoses with the testicular artery. On the posterior aspect of the anterior abdominal wall, the inferior epigastric artery forms the lateral umbilical fold. Rupture of the inferior epigastric artery occurs during forceful bout of cough, strong muscular contractions and blow on the anterior abdominal wall in pregnant women. It forms the painful tense swelling at the lateral border of the rectus abdominis muscle. It is important to remember that the bleeding from the inferior epigastric artery can be disastrous as the large quantity of blood gets collected in the closed space. Twisted ovarian cyst in the female and appendicular abscess in both the male and female have to be considered. It can be mistaken for the Spigelian hernia, which presents as the swelling with vomiting, while in the haematoma formed by the ruptured interior epigastric artery, vomiting is singularly absent. Anastomotic channel formed by the pubic branches of inferior epigastric and the obturator arteries form the abnormal obturator artery in 30% of cases. When it passes lateral to the femoral ring it is safe. However, when it passes along the medial margin of the femoral ring directly lies on the pectineal part of the inguinal ligament. It is likely to get injured unintentionally during the release of the neck of the strangulated femoral hernia.

Figure 264 Abnormal obturator artery having unsafe course (A) Abnormal obturator artery having safe course (B)

Deep Circumflex Iliac Artery:

It arises from the external iliac artery near the origin of the inferior epigastric. It lies in the extraperitoneal tissue, goes laterally towards the anterior superior iliac spine and follows the iliac crest. It anastomoses with the branches of the ilio lumbar and the superior gluteal arteries. It pierces the fascia transversalis and follows the line of attachment of the fascia iliaca, the fascia transversalis and the inguinal ligament. Proximal to the anterior superior iliac spine it gives an ascending branch which appears between the transversus abdominis and the internal oblique muscles. Main trunk of the artery comes midway between the anterior superior iliac spine and the midpoint of the iliac crest where pierces the transversus abdominis muscle and divides into number of branches.

Muscles of the Anterior Abdominal Wall Clinical:

Superior Epigastric Artery:

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The incision at the MackBernys point for appendicitis is likely to damage the ascending branch of the deep circumflex iliac artery and the iliohypogastric nerve. The internal thoracic mammary artery divides at the level of 6th costal cartilage into the superior epigastric and the musculophrenic arteries. Superior epigastric artery enters the rectus sheath and anastamoses with the inferior epigastric artery the branch of the external iliac artery behind the rectus abdominis muscle in the rectus sheath.

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HERNIA It is the protrusion of a viscus or part of a viscus through the abnormal opening in the wall of the cavity of its contents. Following are the common varieties of hernias: 1. Inguinal-direct and indirect. 2. Femoral 3. Umbilical 4. Hiatus hernia 5. Obturator 6. Lumbar 7. Incisional - Following operation 8. Littre’s (Meckel’s diverticulum is the content) Anatomy of hernia (Figure 265): It has 1. Neck 2. Body 3. Fundus 4. Contents and the 5. Coverings. Figure 265 Showing anatomy of hernia

Inguinal hernia: As already stated it can be of indirect or direct. Indirect Inguinal Hernia (Figure 266):

The Coverings of the Sac:

Hernial sac consists of neck, body, fundus, coverings and the contents as an anatomical part of the hernia. It must be remembered that hernia is peculiar to the human beings and is considered as the price paid for the erect posture. A peritoneal protrusion (processus vaginalis) passes through the deep inguinal ring and comes out through the superficial inguinal ring. Inside the processus are the abdominal contents, omentum and the small intestine being the commonest. Neck of the sac lies at the deep inguinal ring and is medially related to the inferior epigastric artery. They are as under from out side in and required to expose the hernial sac. 1. Skin 2. Dortus 3. External spermatic fascia 4. Cremasteric fascia

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Figure 266 Showing indirect inguinal hernia with covering. Note it’s neck of hernial sac lies lateral to inferior epigastric artery

5. 6. 7. 8. Embryological Background (Figure 267):

Internal spermatic fascia Extraperitoneal fat The peritoneum The contents Indirect inguinal hernia lies lateral to the interior epigastric artery. Inguinal bursa is an out pouching of the layers of the anterior abdominal wall, running towards the scrotum. Testis reaches the scrotum through the inguinal bursa which forms the inguinal canal. Inguinal bursa is formed first and the testis enters the bursa later. The descent of the testis through the anterior abdominal wall is responsible for the formation of the inguinal canal. Along with the testis the peritoneal process known as processus vaginalis follows. Processus vaginalis is invaginated by the testis from behind. The part of the peritoneal sac which forms the covering of the testis in the form of a closed sac is known as tunica vaginalis testis. The layer which covers the testicular surface is known as visceral layer and the layer which covers the scrotal sac from inside is known as parietal layer. In between the two layers is the potential space containing small amount of fluid. Excessive collection of the fluid in the closed sac is known as hydrocoel. Part of the processus vaginalis lying in the inguinal canal gets obliterated and remains in the form of a thin fibrous band. It is not uncommon for the processess to remain patent. In such cases peritoneal cavity communicates with the cavity of the tunica vaginalis testis and is accompanied by the congenital indirect inguinal hernia. Types of indirect inguinal hernia : 1. Bubonocoel (Hernia is limited to inguinal canal) 2. Funicular (Reaches the epididymis) 3. Complete (Reaches the scrotum)

Figure 267 Showing three types of oblique inguinal hernia

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Surgical Anatomy of Inguinal Canal in Infants and Children: Direct Inguinal Hernia:

Superfical and the deep inguinal rings overlap each other and there is hardly any inguinal canal. The operation required for hernias in infants and children is the herniotomy (excision of the sac). Herniation of the abdominal contents through the inguinal triangle (Hasselbach’s triangle) is known as the direct inguinal hernia. It lies medial to the interior epigastric artery. It has a wide opening, hence pops up to the surface during standing and falls back in lying down position. The chances of obstruction in the direct inguinal hernia are the least. It is divided into the medial and the lateral direct inguinal hernia. Medial direct inguinal hernia passes through conjoint tendon while the lateral direct inguinal hernia passes through the fascia transversalis (Figure 268).

Figure 268 Showing course of direct inguinal hernia. Note that the direct inguinal hernia is medial to the inferior epigastric artery

Synopsis on the Femoral Canal:

Femoral Hernia:

Umbilical Hernia:

Exomphalos:

It is the medial most, shortest and the relatively empty compartment of the femoral sheath. Its length is 1.25 cm. It opens in the abdominal cavity through the femoral ring. Femoral canal performs three roles namely the anatomical, physiological and the surgical. 1. Anatomical: It acts as the house for the gland of Cloquet and a road for the lymphatics. 2. Physiological: It allows dilatation of the femoral vein during increased venous return from the lower limb as in excercise. 3. Surgical: It is the site for the femoral hernia in the female. Protrusion of the abdominal contents through the femoral canal is known as femoral hernia. It is common in female due to the larger distance between the anterior superior iliac spine and the pubic tubercle. The neck of the hernial sac is situated at the femoral ring. A small depression formed by the peritoneum overlaps the ring. However, thickned extra peritoneal tissue forms the femoral septum. Femoral septum intervenes between the opening of the ring and the peritoneum. Femoral ring is bounded in front by the inguinal ligament, behind by the pectineal line, laterally by the external iliac vein and medially by the sharp cresentic edge of the pectineal part of the inguinal ligament. After its decent through the femoral canal the hernial sac protrudes anteriorly through the saphanus opening and goes upwards towards the anterior abdominal wall. During embryonic stage umbilicus is the site for the physiological herniation of the midgut which is reduced and the umbilicus assumes an appearance of umbilical scar. Persistance of the defect leads to umbilical hernia. It is also known as omphalocele. It occurs due to failure of the midgut to return to the abdomen. At times it is covered by amniotic membrane, layer of Wharton’s jelly and the peritoneum.

Hernia Umbilical Hernia in Infants and in Children:

Paraumbilical Hernia of the Adult:

Treatment: Mayo’s Operation:

Spigelian Hernia: Lumbar Hernia:

Gluteal Hernia: Sciatic Hernia: Epigastric Hernia (Figure 269):

Obturator Hernia:

Figure 269 Showing epigastric hernia in sagittal section

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It occurs throughout the umbilical scar which is weak. Symptomless hernia causes pain during crying, as the hernial swelling increases and, makes the child cry more and more. Chances of obstruction and strangulation are almost nil up to the age of two. Masterly, inactivity by not doing any surgery, cures the patient. In case the masterly inactivity fails, the child is subjected to surgery (Herniotomy). It is also known as supra- and infraumbilical hernias. It does not occur through the umbilical scar but comes through linea ulba above or below the umbilicus. As the neck of the hernial sac is small and the contents are bulky (greater omentum), small intestine, the hernial sac gets loculated. It is commonly seen in the women around the age of 35 to 50. Repeated pregnancies and obesity are the factors. Due to the traction on the transverse colon and the stomach patient complains of dragging pain in the epigestrium. The hernia can become irreducible and strangulated. It should be operated without delay, however the surgeon must tell the patient to reduce her weight. Through a transverse curved incision, the neck of the sac is exposed and incised. Contents are pushed inside. The sac is removed and the neck is closed with catgut. Rectus sheath is cut transversely and upper and the lower flaps are overlapped and sutured (Mayo’s double breasting operation). It is an interparietal hernia situated at the arcuate line lateral to the rectus abdominis muscle below the umbilicus. It is associated with the lower lumbar triangle of Petit. The base of the triangle is formed by the iliac crest, anterior limit by the external oblique muscle of abdomen and posterior by the latissimus dorsi. Superior lumbar triangle is limited by 12th rib above, sacrospinalis muscle medially and the internal oblique muscle laterally. This is the common site for the incisional lumbar hernia following surgery on the kidney. It passes through the greater sciatic foramen either above or below the piriformis muscle. It passes through the lesser sciatic foramen. Extra-peritoneal fat protrudes through the gap in the linea alba which is followed by the peritoneal protrusion. It is commonly seen in children and is usually associated with the divarication of the recti. Many cases do not require surgery as they get automatically cured. It is interesting to note that the patient of epigastric hernia may complain of pain similar to that of peptic oesophagitis. In these cases neither the patient is aware of his epigastric hernia nor the clinician is an experienced observer. It occurs through the obturator canal and is common in women. Swelling in the femoral triangle is rarely seen. Patient keeps the lower limb flexed. Referred pain is felt in strangulated obturator hernia along the obturator nerve at the knee. On per-viginal or per-rectal examination a clinician may feel a tender swelling. The strangulated obturator hernia is operated

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Divarication of the Recti (Rectus Abdominis): Treatment: Surgical Incisions of the Anterior Abdominal Wall:

after laprotomy incising the obturator fascia parallel to the obturator nerves and the vessels. In order to prevent the recurrence of the hernia, the broad ligament of the uterus is fixed over the opening in female. It is commonly seen in elderly women. Abdominal contents come out through the gap between the recti. One can pass fingers in between the recti. As the gap is large the chances of strangulations are the least and surgery is not indicated. In babies, divarication of recti is seen above the umbilicus and gets cured as the child grows. It is the commandment for surgeons in unrelieved case of an intestinal obstruction as “Sun should not rise or set on a case of unrelieved intestinal obstruction” (Figure 270).

Figure 270 Showing surgical incisions of anterior abdominal wall

Paramedial Incision:

The surgeon is required to revise anatomy of the anterior abdominal wall: 1. Langer’s lines- incision given along the Langer’s line do not give unsightly scar and the healing is quicker. 2. Direction of the muscle fibres. 3. Direction of the nerves. 4. As regards the blood vessels are concerned they can be cut as there is a profuse anastomosis between the arteries and the operative incisions are of no practical value. Number of incisions are described in the textbooks, only some of them which are commonly used are described. It lies 4 cm away from the midline and is parallel. After incising the skin and the superficial fascia the surgeon reaches the anterior wall of the rectus sheath and open the sheath vertically. Rectus abdominis muscle is pulled laterally which exposes the posterior wall of the rectus sheath. The incision in the posterior wall of the rectus sheath passes through. 1. Posterior wall of the rectus sheath 2. Fascia transversalis 3. and the peritoneum. As the nerve supply of the rectus abdominis comes from the lateral side its displacement does not damage the nerves. Nerve supply of the rectus abdominis is segmental having no anastomosis between the two nerves. Cutting of the nerve to the segment of the rectus abdominis muscle is the permanent loss of the segmental nerve supply. Lower margin of the posterior wall of the rectus sheath presents an arched line known as the arcuate line. Below the arcuate line the posterior wall of the rectus sheath is formed by the fascia transvalis and the peritoneum. Inferior epigstric artery the branch of the external iliac artery is seen crossing the arcuate line of Douglas. In the low paramedial incision the inferior epigastric artery may be divided between ligatures (Figure 271).

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Figure 271 Showing the tissues cut in the paramedian incision of the anterior abdominal wall. Please note that rectus abdominis is retracted laterally nerve supply of the muscle is not disturbed

Transverse Incision: Pararectal Incision: Subcostal Incision:

Gridiron Incision for Removal of the Appendix (Figures 272 and 273):

Thoracoabdominal Incisions:

Figure 272 Showing McBurney’s incision for removal of an appendix. Please note that ascending branch of deep circumflex iliac artery and iliohypogastric nerve are in danger Figure 273 Showing McBurney’s incision

It is not commonly used as it requires the division of the rectus abdominis muscle. In this incision the anterior wall of the rectus sheath is incised and the rectus abdominis muscle is pulled medially. This incision is not popular as it requires the separations of tendinous intersections from the anterior surface of the rectus abdominis muscle at three places. It is given on right side for the surgery of the gall bladder and on the left side for removal of the spleen. The incision is parallel to the costal margin. In this incision the 8th intercostal nerve has to be sacrificed, however the other nerves remain safe. Subcostal incision has a great advantage in patients with wide subcostal angle. When the subcostal angle is narrow the paramedian incision is used. Center of this incision lies at the meeting of the lateral one-third and the medial two-thirds of the line joining the anterior superior iliac spine and the umbilicus. The incision is given at the McBurney’s point across the spinoumbilical line in the direction of the fibers of the external oblique muscle. Aponeurosis of the external oblique muscle is cut in the line of incision. Internal oblique and transversus abdominis muscles are split in line of their fibers and are separated without cutting with the help of an artery forceps. After the operation the muscles separated by the artery forceps spring back to their places. The upper end of the paramedian incision or the oblique abdominal incision can be carried further through the interval of the 8th or the 9th intercostal space. Diaphragm is required to be cut. It is used for tumours of the cardiac end of the stomach or the lower end of the oesophagus. It can be used for resection of right lobe of liver on the right side.

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Paracentesis of Abdomen:

Rotation of the Gut:

Figure 274 Showing herniation of midgut loop in the coelom

Large collection of intra-peritoneal fluid is removed by the canula through the anterior abdominal after emptying of the urinary bladder, in the midline through the linea alba. The needle can also be introduced lateral to the MacBurny’s point to avoid the injury to the inferior epigastric artery. Surprisingly, the coils of the intestine being mobile move away from the tip of the needle or trocar. Gut is divided into three, foregut, midgut and the hindgut. Artery of the foregut is coeliac, the midgut is superior mesenteric and that of the hindgut being the inferior mesenteric artery. Midgut herniates out side the abdominal cavity in the extraembryonic coelom, near the umbilical opening. The loop of the midgut which lies cranial to the artery is known as pre-arterial segment and the loop caudal to the artery is known as post-arterial segment. Post-arterial segment shows a small dialatation which becomes the caecum. If seen from the front the pre-arterial segment is above and the post-arterial segment below the artery (in sagittal plane) (Figures 274, 275). 1. The loop undergoes an anti-clockwise rotation of 90° and the vertical loop becomes horizontal. In this position pre-arterial segment comes to the right and the post-arterial segment to the left. 2. Pre-arterial segment elongates rapidly to form the coils of the jejunum and the ileum. 3. The coils of the jejunum and the ileum (Pre-arterial segment) starts returning to the abdominal cavity). During their return the midgut loop undergoes a further anti-clockwise rotation. Due to this the mass of coils of jejunum and ileum goes behind the superior mesenteric artery to left side of the abdominal cavity being first to return. As a result the duodenum lies posterior the artery. 4. Finally, the post-arterial segment of the midgut returns to the abdominal cavity. During return it undergoes an anti-clockwise rotation and the transverse colon lies anterior to the superior mesenteric artery. Caecum lies under the liver. It descends in the

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Figure 275 Showing vertical disposition of the pre- and postaxial loops

Figure 275A Showing anticlockwise rotation of pre-axial loop to the right and the postaxial to the left. Right axial loop undergoes 180° of anti clockwise rotation. Left axial loop undergoes further 180° of anticlockwise rotation

Fixation of Gut:

Developmental Anomalies of the Gut:

right iliac fossa. At this stage ascending, transverse and the descending colon can be identified. Initially, small intestine and the large intestine have mesenteries which attach them to the posterior abdominal wall. However, after the rotation of the gut the duodenum, ascending colon, descending colon and the rectum loose their mesenteries as they get fused with the posterior abdominal wall. Small intestine, transverse mesocolon and pelvic colon retain their mesenteries. They are as under: 1. Atresia: It is the failure of canalisation. 2. The segment of the gut may be missing and may be represented by fibrous tissue or may present as the septum dividng the lumen. 3. Stenosis: Abnormal narrowing of the lumen is known as stenosis. 4. Failure of the development of the nerve plexus in the wall of the large intestine results in obstruction to the passage of content. The part of the gut proximal to the defect is dilated. It is seen in congenital mega-colon or Hirschsprung’s disease. 5. Congenital pyloric stenosis: The circular muscle coat of the pylorus gets hypertrophid and reduces the lumen of the pylorus which may allow hardly the tip of the probe. 6. Formation of bands: Fibrous band may obstruct the duodenum by the cystocolic band which extends from the transverse colon to the gall bladder across the duodenum. 7. Imperforate anus: There is failure of disappearance of the membrane separating the rectum above and the anal canal below.

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SPERMATIC CORD It is the thick cord containing the vas deferens, artery of the vas, testicular artery, cremastric artery, pampiniform plexus, lymphatics, remnant of processes of vaginalis and genital branch of genitofemoral nerve. It extends from the upper pole of the testis to the deep ring. As it passes through the superficial ring and the inguinal canal, it acquires coverings of external spermatic fascia, cremasteric fascia and the internal spermatic fascia from outside in. Artery of the vas is the branch of inferior vasical artery, while the cremasteric artery is the branch of inferior epigastric artery. The artery of the vas and the cremasteric arteries anastomose with the testicular artery. It acts as the additional source of blood supply for the testis and prevents infarction and atrophy of the testis in case of accidental ligation of the testicular artery. Pampiniform plexus is a network of veins which is replaced by one or two testicular veins at the deep ring. Right testicular vein drains into the inferior vena cava and the left into the left renal vein (Figure 276). Figure 276 Showing cross-section of spermatic cord and its contents with coverings

Clinical: Tunica Vaginalis Testis:

Bilateral ligation and cutting of the vas deferens through small incision is widely practiced as a measure of family planning (vasectomy). It is a closed sac invaginated by the testis from behind, leaving its posterior border uncovered. The layer which covers the testicular surface known as visceral and one which covers the scrotal sac from inside the parietal. Between the testis and the body of the epididymis lies the sinus of the epididymis lined by the visceral layer of the tunica.

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TESTIS

Appendix of the Testis:

Figure 277 Showing testis and epididymis

Figure 278 Showing sagittal section of testis, tunica vaginalis testis and mediastinum testis with rete testis

Testies are the male gonads located in the scrotal sacs, separated by an incomplete septum. Testis is suspended in the scrotum by the spermatic cord. It has an oblique position and its upper pole fasces forwards and medially. Testis is oval in shape. Vertical measurement is 4 cm transverse 2.5 cm and the anterior-posterior measurement is 3 cm. It is an important organ where the spermatozoa are formed. It is covered with the tunica vaginalis on all the side except the posterior border which is directly related the epididymis and the vas. The left testis lies at a lower level than the right due to the fact that it reaches the scrotum first. It has upper and lower poles, anterior and the posterior borders, medial and the lateral surfaces. Its posterior border is related to the head, body and the tail of the epididymis. The head of the epididymis forms the crown for the upper pole of the testis. Number of small ducts of the testis join the head of epididymis. They are known as vasa efferentia. They carry spermatozoa from testis to the epididymis and finally to the vas deferens. Vas deferens begins from the tail of epididymis ascends along the posterior border of testis, lying on the medial side of the epididymis. This helps in identification of the side of the testis. Between the testis and the body of epididymis the depression lined by the visceral layer of the tunica, is known as sinus of the epididymis (Figures 277 and 278). It is the small oval body situated at or near the upper pole of the testis. It is a remanant of the upper end of the paramesonophric duct (Hydatid of Morgagni).

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Figure 279 Showing histology of testis

Histology (Figure 279):

Development (Figures 280 and 283): Figure 280 Showing development of testis

Testis has three coverings from outside in: 1. Tunica vaginalis: It is the visceral layer of tunica vaginalis testis. 2. Tunica albuginea forms the second layer: It is dense and white. The bare area on the posterior border of the testis is for entry of the testicular vessels and nerves. Tunica albuginea forms the thick vertical septum inside the substance of the testis which projects from the posterior aspect. Multiple septae run from the mediastinum to the tunica albuginea, thus dividing the testis into lobules. 3. The third coat of the testis is vascular: The total number of lobules in the testis are around 200 to 300. Each compartment, has two convoluted seminiferous tubules. As they run posteriorly they form the complicated plexus in the substance of the mediastinum testis. It is known as the rete testis. From the rete testis, fifteen to twenty ducts join the epididymis. Microscopic section through the tubule shows well-defined basement membrane and a lining of many layered cells. From outer to inner they are: 1. Primary spermatocyte, 2. Secondary spermatocyte, and 3. The spermatid. Placed in between the cell, pyramidal cells are seen extending from the basement membrane to the lumen. These cells are responsible for the nutrition of the spermatids, and are known as nurse cell (cells of Sertoli). In between the tubules, connective tissue, blood vessels the interstitial cells are seen. They are known as Leydig cells. They are polyhydral in shape and secrete testosterone. Testis is mesodermal in origin and develops from coelomic epithelium. Germ cells are derived from the wall of the yolk sac. It develops in the lumbar region and descends into the scrotum.

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Figure 281 Showing anastomosis of testicular artery with artery of vas and cremasteric branch

Mesonephric duct and the tubules form the ductal system of the testis. Interstitial cells of the testis are non canalized cell derived from sex cords and possibly from the surrounding mesenchyme. Tunica albuginea a thick fibrous coat is formed by the mesenchyme surrounding the testis. Testis reaches the iliac fossa in the 3rd month of intrauterine life. Testis is at the deep inguinal ring at the sixth months of intrauterine life. It reaches the canal at the seventh month and the superficial inguinal ring at the 8th month of intrauterine life. Gubernaculum is the thick band of mesenchymal tissue between the lower pole of the testis and the floor of the scrotum. Anomalies of the testis (Figure 282): 1. Absence 2. Duplicated 3. Fusion 4. Undescended testis: The organ does not come out of the abdomen (cryptoorchidisum). 5. Anteverted testis—The epididymis instead of lying behind lies infront. 6. Inverted testis—In this condition the testis is hanging upside down, its upper pole being lower and the lower being upper. Figure 282 Showing types of testis

Undescended Testis:

Testis may not descend into the scrotal sac and may remain in the abdominal cavity (undescended testis). Undescended testis has following risk: 1. Sterility due to degeneration at the age of 16 years 2. Pain due to injury 3. Hernia 4. Torsion 5. Atrophy 6. Malignancy

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Figure 283 Showing development of mesonephric duct

Ectopic Testis:

The testis is well-developed however takes the different path after the descent. It is subjected to injury due to its unusual position. Sites of ectopic testis: 1. Superficial inguinal ring 2. Perineum 3. Root of the penis 4. Femoral triangle Descent of the testis is attributed to the following factors. 1. Gubernaculum testis. It get shortened and pulls the testis down. 2. Disproportionate growth of the posterior abdominal wall especially the internax oblique. 3. Intra-abdominal pressure. 4. Hormones of anterior lobe of the pituitary. 5. Squeezing action of the muscles of the anterior abdominal wall especially the internal oblique.

Retractile Testis:

Orchioplexy:

Blood Supply (Figure 281):

Retractile testis is seen in children. Testis retracts into the inguinal canal after stroking the medial aspect of the thigh, due to contraction of the cremaster muscle. In retractile testis the scrotum is well-developed and the testis can be brought to the bottom of scrotum. While in undescended testis, cannot be brought into the scrotum. Undescended testis is poorly developed along with the scrotum. After mobilisation and the lengthening of the spermatic cord, testis is brought into the scrotum. The division of fibrous bands and the separation of cremasteric vessels help in lengthening the cord. It can be attached to the bottom of scrotum by non-absorbable suture. It can be put in the pouch formed between the skin and the dortus muscle. It can be lodged in the scrotal sac of the opposite side through the scrotal septum which is formed by dortus muscle (Ombredanne’s operation). Testies are supplied by the testicular branches of the abdominal aorta. Each testicular artery arises from the abdominal aorta near the origin of the the renal arteries. It descends on the posterior abdominal wall crosses the ureter and the external iliac vessels to reache the deep inguinal ring. It passes through the deep ring, inguinal canal and comes out through the superficial inguinal ring. It is one of the constituents of the spermatic

Testis

Venous Drainage (Figure 284):

Clinical:

Tortion of the Testis:

Figure 284 Showing cause of recurrence of varicocele after ligation of the testicular vein. Note: The back flow through cremasteric vein

Figure 285 Showing venous drainage of suprarenals and testies

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cord. Artery of the vas a branch of the superior vesical artery and the cremastric artery is the branch of the inferior epigastric artery also supply the testis as they follow the vas. The artery of the vas and the cremastric arteries anastomose with the branches of the testicular artery provide an alternative blood supply to the testis. Due to the alternative blood supply, ligation of the testicular artery does not cause testicular atrophy. Testicular venous plexus is in the form of a network which accompanies the spermatic cord. It is known as the pampiniform plexus. It passes through the superficial inguinal ring, inguinal canal and comes out of the deep ring where it is replaced by one or two testicular veins. Right testicular vein drains into the inferior vena cava and the left testicular vein into the left renal vein. In cancer of the left kidney (hypernephroma), left renal vein gets blocked by the cancer cells. This leads to obstruction of the left testicular vein resulting in varicocele of the left testis. (Hypernephroma of the left kidney may announce its presence through the left sided varicocele (Figure 285). Rotation of the testis is favoured by following factors: 1. Inversion of testis - testis is upside down. 2. High extension of tunica vaginalis testis.

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Mechanism:

Forceful contractions of the abdominal muscles help the cremaster to contract. The spiral loops of the cremaster promote rotation resulting in torsion of the testis. Clinical: How to differentiate between epididymoorchitis and torsion of the testis: Elevation of testis brings relief of pain in epididymorchitis. While the elevation of the testis makes the pain worst in the torsion. Note: Appendix of the testis if pedunculated can undergoes rotation. (Hydatid of Morgagni). Malignant Commonest tumor of the testis is the seminoma (40%) and the next Tumors of the common being the teratoma (30%). Teratoma occurs in younger age Testis: group (between 20 to 30). It arises from totipotent cells in the rete testis. Seminoma arises from the cells of seminiferous tubules and is never seen before puberty. Majority of the cases of the teratoma present with a lump in the epigastrium. Hurrican Tumour: It is an extremely malignant teratoma of the testis which kills the patient in few weeks. The 99% of the tumors of the testis are malignant; and almost all of Paradox of the Testicular them are diagnosed after metastasis. This is in spite of the fact that the testis is superficially placed in the bag of skin which is easily Tumours: approachable and visible. This can be called as the Paradox of the testicular tumours. In advanced cancer of the prostate with metastasis bilateral orchidectomy Orchidectomy: is done to remove source androgen. Subcapsular orchidectomy is also the method for removal of the source of the androgens. Medical It is the hormonal therapy in which female hormones like oestrogens Orchidectomy: are administered to the patient. Lymphatic Drainage: The lymphatics of the testis is to the aortic group of lymph nodes. Nerve Supply: It is supplied by the 10th and 11th thoracic segments of the spinal cord.

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EPIDIDYMIS

Structure of Epididymis:

Cysts of Epididymis and Testis : Clinical :

Epididymis is an organ which is made of the long coiled tube. It lies along the posterior border of the testis and is placed on the lateral side of vas. It presents the head, body and the tail. A small body situated on the head of the epididymis is known as appendix of epididymis. It is the remnant of mesonephros. It consists of long coiled tube with a lumen. The lumen of the epididymis runs through a coiled tube which forms the body as well as a tail. It is interesting to note that the length of the coiled tube of epididymis is about 600 cm (20 ft). As already stated the tail of the epididymis continues as the vas deferens. Note: Length of the tube of the epididymis probably is with following objects. 1. Provision of large space for storage of the spermatozoa. 2. During long journey provides time for the maturation of the spermatozoa. 3. Absorption of fluid. 4. Provision of nourishment to the spermatozoa. Cysts associated with epididymis contain closed membranous sacs with clean fluid inside. Appendix of the epididymis is the remnant of the mesonephric duct while the appendix of the testis is the remnant of paramesonephric duct. Cysts of the epididymis are due to cystic degeneration of the following– A. Paradidymis (organ of Giraldes) B. Appendix of the epididymus: Pedunculated hydatid of Morgagni C. Appendix of the testis (Sessile hydatid of Morgagni): It can under go torsion. 1. Orchitis is inflammation of the testis. 2. Epididymo-orchitis is the inflammation of the epididymis and the testis. 3. In tuberculosis of the epidydimis, it is enlarged and beaded and can be felt perrectally. 4. Testicular biopsy is done in cases sterility due to azospermia (Absence of sperms in seminal fluid). Azoospermia can occur as a result of block in the conducting tube (vas). Vasography is done for detecting the site of the block. In such cases excision of the affected segment with anastomosis is done. When the loss of segment is too long due to vasectomy, the vas can be anastomosed to the epididymis. (Vasoepididymostomy). Infertility in the male can be due to following causes. 1. Failure of testis to produce adequate number of normal sperms. It can result in azoospermia or oligostermia). Mumps, radiations and the testicular trauma are the main causes. 2. Obstruction of the vas can lead to azoospermia. The testicular biopsy shows normal functioning of the testicular tissue. The block in the vas can be detected by vasography. 3. Immunological causes : There is clumping of the sperms when exposed to the cervical mucus.

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ABDOMINAL CAVITY AND PERITONEUM

Greater Sac: (Figures 286 to 288)

Shape of the abdominal cavity is roughly oval. Its vertical axis being longer than the transverse. The cavity proper is reduced to the considerable extent by the anterior projection of the vertebral column and the muscles of the posterior wall. The distance between the anterior and the posterior walls of the abdomen is reduced in the umbilical region. This is due to the projecting convex lumbar part of vertebral column. Abdominal cavity is roofed by the great muscular partition known as the diaphragm. Below and behind, the abdominal cavity communicates with pelvic cavity. Lying inside the abdominal cavity is the closed peritoneal sac. It has the parietal and the visceral layers. The peritoneal cavity lies between the parietal and visceral layers. It contains small amount of fluid which permit rolling of the organs without friction. The peritoneal cavity is the largest cavity of the body and yet remains empty. Surface area of the peritoneum is equal to the total surface area of the body. The abdominal cavity is filled to its maximum capacity with the organs while the peritoneal cavity remains empty. Peritoneal cavity being the closed sac, all the contents lie in the abdominal cavity and the peritoneal cavity remains empty (Poverty in the Land of Plenty). Structures are attached to the posterior abdominal wall by means of peritoneal folds. They are described as the mesocolon and the mesentery. Other folds of the peritoneum which help in fixing the organs are described as the ligaments. Arrangement, of the folds of the peritoneum leads to the formation of small pockets. Out of these, the spaces below the diaphragm are clinically important (sub-diaphragmatic spaces). Others are described as recesses namely the recess of the pelvic mesocolon, retrocoecal recess and the duodenal recesses. Shallow grooves lined by the pertoneum on the lateral aspect of the ascending and descending colons are known as paracolic gutters. It is the left paracolic gutter which can be followed with ease into the pelvic cavity along with the pelvic colon making it easy for infected abdominal contents to enter the pelvic cavity. For the understanding of the arrangement of the peritoneum one vertical and two transverse sections of the cavity are drawn. In the vertical section draw the liver, stomach, transverse colon and the small intestine from above downward (sequence of drawing the organs from above downwards can be remembered as LSTS (Longitudinal Section Transverse Section) L- liver, S – stomach, T- transverse colon, S – small intestine. As soon as the peritoneal lining of the anterior abdominal wall is opened, what one examines, is the cavity of greater sac. An entry into lesser sac is possible if two anterior layers of greater omentum are incised. This should be considered as a shortcut. There exists the natural gate which connects two sacs. It is known as the aditus to the lesser sac (foramen of Winslow). It is bounded anterior by a double fold of peritoneum the layers of which are continuous with each on the right side to form the free margin of the lesser omentum. Lesser omentum extends between the liver and lesser curvature of the stomach. (Omenta means stomach). The free margin of the lesser omentum forms anterior limit of the aditus. It contains the portal vein, hepatic artery and the common bile duct. It is bounded by the caudate lobe of the liver

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above, first part of duodenum below and inferior vena cava behind. The small dilated part of the lesser sac, lying on the left of the aditus is known as vestibule. Figure 286 Sagittal section through abdomen and pelvic showing vertical tracing of the peritoneum

Figure 287 Showing transverse section tracing of peritoneum at the level of aditus viewed from above

Figure 288 Showing transverse tracing of peritoneum at the root of mesentery (viewed from above)

Lesser Sac:

As the name indicates it is the sac of the small size inside the big sac. The lesser sac is bounded anteriorly by the liver, lesser omentum, stomach and the anterior two layers of the greater omentum. Posteriorly it is bounded by the diaphragm, posterior abdominal wall, transverse mesocolon, transverse colon and the posterior two layers of the greater omentum (From above downwards). Formation of the lesser sac is as the result of rotation of the stomach to the left.

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Kadasne’s Textbook of Anatomy (Clinically Oriented) Functions of the peritoneum: 1. Forms lining for viscera and protects. 2. Keeps viscera in normal position by forming folds and ligaments. 3. Provides passage for the blood vessels and the lymphatics. 4. Prevents adhesion. 5. Absorptive function – Pelvic peritoneum is less absorptive than the diaphragmatic. Patient of peritonitis is nursed in Fowller’s position so that infective material collects in the pelvis where rate of absorption is less due to the thickness of the pelvic peritoneum and lesser movements as compared to the diaphragmatic peritoneum. 6. Peritoneal dialysis in renal failure is done due to its excretory function.

STOMACH Introduction:

Capacity (Figure 289):

Stomach is also known as gaster. It is the large distendable muscular bag situated between the oesophagus above and the duodenum below. It acts as the receptor and the storage organ for the food. It helps in mixing the food with gastric juices and convert it into the chyme. It produces hydrochloric acid, mucous, gastrin and the intrinsic factor which help in absorption of vitamin B12. Alcohol gets rapidly absorbed from the stomach. 1. 30 to 50 cc at birth (i.e. equal to the capacity of the gallbladder). 2. 1000 ml at puberty. 3. 1.5 to 2 ltrs in adults.

Figure 289 Showing stomach

Capacity of the stomach depends upon the type of diet and the quantity. It is more in those who eat rice, maize and vegetables in large quantity. Stomach is situated in the upper and the left quadrant of the abdominal cavity. In relation to the surface divisions of the anterior abdominal wall, it occupies the left hypochondriac and the epigastric regions. However, a small part of it is situated on the right side of the median plane. It presents the fixed cardiac or upper end and relatively mobile pyloric or lower end, lesser curvature, greater curvature, antero-superior and the postero-inferior surfaces. Cardiac end lies at the level of 10th costal cartilage and the pyloric at the first lumbar level (Transpyloric plane) 1.2 cm to the right of the median plane. The cardiac end is related to the left lobe of liver in front. Long axis of the stomach is directed downwards forwards to the right and backwards. Lesser curvature presents the notch in the lower part known as the incisura or angular notch. Lesser curvature gives attachment to the lesser omentum. The angular notch indicates the limit of the body and the

Abdominal Cavity and Peritoneum

Parts of the Stomach (Figure 291):

Clinical :

Inferior of the Stomach:

Pylorus :

Congenital Pyloric Stenosis:

Peritoneal Folds of Stomach: Lesser Omentum (see Figure 290):

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pyloric portion. Pyloric portion is further divided into the proximal pyloric antrum and the distal pyloric canal. Important relations of lesser curvature are the omental tuberosity of the pancreas and the anastomosis between the right and left gastric arteries. Attached to the greater curvature are the gastrosplenic; gastrophrenic ligaments and the greater omentum. Greater omentum is described as the “Policeman of the abdomen” (Rutherford Morrison). It limits infection, and plugs the hernial openings to prevent the abdominal contents from leaving the abdominal cavity. It is shorter in children which aggravates problem in acute abdomen. Its shorteness is blamed for higher mortality of children in acute abdomen. Right and the left gastro-epiploic arteries anastomose along the greater curvature. Part of the stomach which lies above the level of the cardiac orifice is known as fundus. Normally it contains air which gives a dark shadow below the left dome of diaphragm in a plain X-ray. The portion between the fundus and pylorus is known as the body of the stomach. Pyloric part is divided into proximal pyloric antrum and the distal pyloric canal. Presence of gas in the fundus of stomach of a newborn is strongly suggestive of the tracheo-oesophageal fistula (Figure 291). Absence of gas in fundus is observed in achalasia cardia. Placed along the lesser curvature is a channel formed by the longitudinal folds of the stomach. It is known as gastric canal. Food and the fluids follow the gastric canal. Consumption of acid and strong alkalies can produce stricture of the stomach along the gastric canal. Rest of the gastric mucosa shows folds. They are known as rugae. They are placed longitudinally along the lessor curvature. Gastric pits can be seen on the mucosal surface with the help of a magnifying glass. Pyloric portion of the stomach as already stated presents pyloric antrum and the pyloric canal. Distal part of pyloric canal presents a well marked circular thickening of muscle known as pyloric sphincter. Pyloric opening if viewed from duodenal side resembles view of cervix uteri seen from below. Anteriorly it is related to the quadrate lobe of the liver. Prepyloric vein of Mayo which lies in front of the pylorus acts as an important guide for the surgeon. It is commonly seen in the first male child born to the highly intelligent parents. Hypertrophy of the pyloric sphincter leads to formation of the lump and narrowing of the lumen which leads to obstruction. Its main symptoms and signs are the vomiting, palpable lump and the visible peristalsis. It is operated by cutting the hypertrophied sphincter partially with the knife and separating it with artery forceps till the mucosa prouts into the wound (Ramsted’s operation). They are two in number, the lesser and the greater: It is the double fold of the peritoneum extending between the liver and the lesser curvature of the stomach. Its right margin is free and rounded. It forms the anterior boundry of the aditus to the lesser sac (Foramen of Winslow). It contains portal vein, common bile duct and the hepatic artery. In case of injury to the liver, bleeding from the wound can be controlled by putting the index in the aditus and the thumb infront. Compression of the hepatic artery helps in arresting the haemorrage and allows the surgeon to repair the liver (Pringel’s Maneuver). Right and the left gastric arteries form an anastomotic channel along the lesser curvature in between its two layers. Lesser omentum contains gastric vessels, lymph nodes, lymphatics, gastric nerves and areolar tissue.

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Figure 290 Omental attachment of 1st part of duodenum which makes proximal half of duodenum mobile

Figure 291 Showing parts of stomach

Greater Omentum:

Gastro-phrenic Ligament: Gastrosplenic Ligaments : Nerve Supply of Stomach :

It hangs down as a four layered apron from the greater curvature of the stomach. It has plenty of fat (store of fat). Two posterior layers of the greater omentum pass anterior to the transverse colon, transverse mesacolon and reach the posterior wall at the lower border of the pancreas. It is the embryonic plane which lies between the greater omentum and transverse mesacolon. The embryonic plane is avascular as it passes between the mesacolic and the omental vessels and does not bleed during separation through the plane. An anastomotic channel between the two gastro-epiploic arteries is placed between the two anterior layers of the greater omentum near the greater curvature of the stomach. As already stated the greater omentum contains large amount of fat and macrophages (Milk fat), extraperitoneal tissue, lymph nodes and lymph channels. It extends from the greater curvature of the stomach to the diaphragm. It is the double fold of peritoneum running from the greater curvature of the stomach to the hilum of spleen. It contains short gastric arteries which are the branches of the splenic. It has sympathetic and the parasympathetic nerve supply. Sympathetic nerve supply comes from spinal segment 7 to 9. Efferent sympathetic fibers contracts the sphincter. Afferent sympathetic fibers carry pain from the stomach to the spinal segments. Referred pain of the stomach is felt at the epigastric region, which is supplied by the spinal segment 7 to 9. Parasympathetic nerve supply comes from the anterior and the posterior gastric nerves. Anterior gastric nerve represents the left vagus. It gives hepatic branch from the right side and the number of gastric branches on the left. Beyond the origin of the gastric branches it is known as nerve of Laterjet which ends at the antrum by giving number of branches which look like crow’s feet.

Abdominal Cavity and Peritoneum Posterior Gastric Nerve:

Anterior Relations (Figure 292):

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Posterior gastric nerve gives the branch to the coeliac ganglion on the right and the criminal nerve of Grassi to the fundus of the stomach on the left. It gives gastric nerves to the posterior surface of the stomach and continues as posterior nerve of Laterjet. It terminates in the form of short branches at the antrum which appear like crows feet. Sympathetic stimulation leads to vasomotor changes of the stomach and it causes spasm of the pyloric sphincter while the stimulation of the parasympathetic relaxes the pyloric sphincter. Relations of the antero-superior surface are as follows: 1. Left lobe of the liver (Visceral surface). 2. Anterior abdominal wall (left rectus abdominis and linea alba). 3. Diaphragm.

Figure 292 Showing anterior relations of stomach (Diagrammatic)

Peritoneal Covering:

Figure 293 Showing structures forming stomach bed

Relations of the posteroinferior surface are as below (Stomach bed) (Figure 293):1. Omental bursa or lesser sac 2. Body of the pancreas. 3. Splenic artery. 4. Left kidney. 5. Left suprarenal gland. 6. Spleen. 7. Diaphragm. 8. Transverse mesocolon. 9. Transverse colon. Stomach is covered with peritoneum on all the sides except a small portion lying behind the cardiac end where the gastrophrenic ligament has an attachment.

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Blood Supply (Figures 294 and 295):

Following arteries supply the stomach: 1. Right gastric - branch of hepatic. 2. Left gastric - branch of coeliac. 3. Right gastro-epiploic - branch of gastro-duodenal which is a branch of hepatic 4. Left gastro-epiploic - branch of splenic. 5. Short gastric – branches of splenic. Note: “BETTER SAY ALL GASTRIC” It has already been stated that the right and left gastric arteries anastomose along the lesser curvature while the right and left gastroepiploic arteries anastomose along the greater curvature. It is worth noting that the branches from these anastomotic channels run at right angle to the long axis of the stomach.

Figure 294 Showing blood supply of stomach

Figure 295 Showing blood supply of stomach and the coeliac trunk with branches

Venous Drainage:

Lymphatic Drainage (Figure 296):

Right and left gastric veins drain into the portal vein, while the short gastric and left gastro-epiploic veins drain into the splenic vein. The right gastro-epiploic vein joins the superior mesenteric vein. In short, blood from stomach goes to the portal vein. Lymphatic drainage of this stomach is important. Lymphatics follow the blood vessels and drain into the coeliac group of lymphatic nodes. Lymphatic drainage is arranged in four groups. 1. Lymphatics from the adjoining area of lesser curvature go to the lymph nodes situated along the left gastric vessels, from there they drain into coeliac group. 2. Lymphatics from the pyloric portion of stomach go to the nodes situated along hepatic artery and coeliac group.

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Figure 296 Showing lymphatic drainage of stomach

Structure of the Stomach:

Development :

Clinical :

3. Lymph vessels from upper part of the area adjoining the greater curvature go to the lymph nodes at the hilum of spleen and reach the coeliac group after passing through the pancreatico-splenic lymph nodes. 4. Lymph vessels from the area adjoining the lower part of greater curvature go to the right gastro-epiploic lymph nodes and further to the coeliac group. 5. Secondaries of the cancer of the stomach may appear in the left supraclavicular region involving the supra-clavicular group of nodes. (Troisier’s sign). Stomach presents serous coat, muscular coat, submucous coat and the mucous coat. Mucous coat presents a well defined basement membrane with tall columnar epithelium and simple tubular gastric glands. Situated amongst the cells of the glands are the oxyntic cells. As regards the muscular coat, it presents three layers from outside in: 1. Longitudinal, 2. Circular, and 3. The Oblique. Gastric epithelial cells produce mucus which lubricates the gastric muscosa. Parietal cells are present in the body of stomach and produce HCL. Chief cells are in the fundus of the stomach and produce pepsinogen. G cells are the endocrinal cells situated in the antrum of the stomach. They secrete gastrin. It is an endodermal in origin and develops from the fusiform dilatation of between the developing oesophagus and the duodenum. It is attached to the body wall by means of dorsal and ventral mesogastrium. As the stomach rotates, its right surface becomes the posterior and the left represents the anterior. Left vagus nerve becomes the anterior gastric trunk and the right vagus nerve becomes posterior gastric trunk. Spleen develops from the mesoderm in the left layer of the dorsal mesogastrium and comes to lie on the left with the rotation of the stomach. Dorsal mesogastrium forms gastrosplenic and lieno-renal ligaments. Rotation of the stomach to the left forms the omental bursa which goes posterior to the stomach. It is important to remember that amongst four causes of chronic haemorrhage, bleeding peptic ulcer is the one. Other three are: 1. Bleeding piles 2. Bleeding fibroid of uterus. 3. Carcinoma of caecum. The importance of the various operations designed for the relief of peptic ulcer has gone down. It is the identification of H. pylori a new light on the genesis of the peptic ulcer is thrown. Gastric mucosa produces

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Peptic Ulcer :

Kissing Ulcer:

Vagotomy (Figure 297):

Selective Vagotomy: Highly Selective Vagotomy: Summary of Vagotomy:

hydrochloric acid, mucus and the gastrin. If the balance between the acid and the mucus is disturbed the protective action of the mucus is diminished and it allows hydrochloric acid to erode the gastric mucosa. Ulcer means a breach in the continuity of the surface epithelium. Peptic ulcer includes gastric, duodenal, lower oesophageal ulcer, anastomotic ulcer and the ulcer of the Meckel’s diverticulum. 1. Peptic ulcer is divided into two categories, i.e. the acute and the chronic. Acute peptic ulcers are small, superficial and they heal earlier without forming the scar. Acute peptic ulcers in the modern days are, drug induced, i.e. ABC. A - Aspirin B - Butazolidine C - Cortisone. (It has been stated that the 25% of haematemesis around London city are due to aspirin.) Note : Please remember the chief and cheap drug which acts as the prophylactic against the coronary thrombosis is the ‘ASPIRIN’ as it prevents clotting of blood. Acute peptic ulcer can cause vomiting of blood (haemetimesis and passing of black stool (melena). Chronic peptic ulcer can lead to following complications: 1. Bleeding 2. Perforation 3. Malignancy. 4. Deformities of the stomach due to fibrosis. As a result of fibrosis occurs after healing of an ulcer, leads to hour glass stomach. The fibrosis along the lesser curvature leads to formation of “tea pot” stomach. First part of the duodenum presents ulcers on the anterior and the posterior walls. The ulcer on the anterior wall can perforate and the contents enter the greater sac. Posterior wall ulcer erodes the gastrodudenal artery leading to the fatal haemorrhage. In case of perforation of the gastric ulcer contents enter the lesser sac of peritoneal cavity. Vagotomy means cutting or sectioning of the vagii, i.e. anterior and the posterior gastric nerves. Please remember here that the left vagus nerve becomes the anterior gastric nerve and right becomes the posterior gastric nerve. In order to improve gastric emptying, pyloro-plasty or gastrojejunostomy was routinely performed. The detail anatomy of the branches of the vagus nerve led to the techniques of selective and the highly selective vagotomy. In selective vagotomy, coelic and hepatic branches are spared, however, the antral branches are cut resulting in delay in gastric emptying. During this operation only the gastric branches are cut which supply the acid producing parietal cells. For the denervation of criminal branch of Grassi, it is carefully identified, dissected and cut. This operation does not require drainage procedure, as the antral branches are spared. 1. Truncal 2. Selective 3. Highly selective

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Figure 297 Showing nerve supply of stomach and highly selective vagotomy. Pyloric branches are not cut as they supply the sphincter

Spread Malignancy of the Stomach:

Carcinoma of the Stomach: Investigation:

Note: The lesser curvature seromyotomy of Taylor is done along the lesser curvature with the help of a laparoscope. The procedure can be combined with the posterior truncal vagotomy. Anteriorly the malignancy gets fixed to the liver and posteriorly to the pancreas. When fixed to pancreas pain felt in the back. Lymphatic spread of the malignancy is mainly to the coelic and hepatic nodes. However, distant spread to the left supraclavicular glands is not uncommon (Troisiers’s sign). 1. Local spread: (Direct) It involves liver, pancreas, colon, oesophagus and peritoneum causing ascities. 2. Lymphatic spread 3. Blood spread 4. Trans-peritoneal spread – gives growths in pelvis of the males and the Krukenberg’s tumour of the ovary in females. It is also seen in advanced cancer of the breast. Malignant cells from the visceral surface liver shower the pelvis like a snow-fall in Himalayas and some of them get implanted on raw surface of the ovary causing Krukenberg’s tumours. Note: In advance case of carcinoma of the stomach the cancer cells can produce nodules around the umbilicus known as Sister Josephs nodules. It is described as “Captains of the men of death”. It is adenocarcinoma and most preferred site is the prepyloric portion of the stomach (more than 60%). 1. Hb as 40% patients are suffering from anaemia. 2. Barium meal studies. 3. Gastroscopy with flexible gastroscope with biopsy. 4. Cytology of the mucosal brushings. Note: In leather bottle stomach there is floried proliferation of fibrous tissue in the submucosa. The stomach wall feels like leather. It is very difficult to dignose gastric carcinoma as mucosa of the stomach looks normal and feels normal. Even the serial sectioning of the tissue fails miserably to find evidence of carcinoma.

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The Diagnostic Pitfall:

I know of a case having dyspepsia for long. Gastroscopy was normal on three occasions. However, the loss of weight continued. Finally X-ray showed the secondary metastasis in the liver. Normal reporting of gastroscopy in linitis plastica or leather bottle stomach, carries little weight.

Volvulus of Stomach:

Volvulus of the stomach occurs along the long axis of the stomach running between the cardiac and the pyloric ends. During valvulus, the stomach gets upside down, i.e. the greater curvature goes up and the lesser comes down.

Tricobazar:

The tricobazar is the hair-ball in the stomach seen in females with psychiatric mental disease. Patient consumes own hair as a perversity.

Spleen

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SPLEEN The spleen is solid friable, vascular and dark purple coloured organ belonging to the reticuloendothelial system. Enlarged spleen can be palpated through the anterior abdominal wall. The notched superior border of spleen, is searched by palpating fingers. Extension of the enlarged spleen is always downwards and towards the right iliac fossa. It is situated in the left hypochondriac region well protected by the left subcostal arch. It measures 2.5 cm in thickness, 7 cm in breadth and 12 cm in length. Its weight is approximately 150 gm. However, this organ is known for its irregular shape and variable sizes. Its axis lies along the 10th upper border along the 9th and the lower border along the 11th rib. Its complete peritoneal covering and the contact with the diaphragm make it move with the respiration. It presents two ligaments namely, the lieno-renal and the gastrosplenic. Lieno-renal ligament is the double fold of peritoneum extending from the front of the left kidney to the hilum of spleen while the gastrosplenic ligament lies between the greater curvature of stomach and the hilum of spleen. The lieno-renal ligament contains splenic artery, splenic vein and the tail of the pancreas (Figure 298). Figure 298 Showing spleen

Functions of Spleen:

Many functions are attributed to the spleen. 1. Antigenic challenge (T and B lymphocytes) 2. Phagocytosis 3. Grave yard for the old and worn out RBCs 4. Site of sequestration for the platelets 5. Storehouse of blood 6. Formation of the blood during the embryonic life from the fourth month of the intrauterine life till the time of birth. Inspite of the fact that spleen has to perform above mentioned functions it is not essential to the life as removal of the spleen hardly affects the working of the human body (splenectomy is compatible with life). Probably it is due to the fact that the other reticulo-endothelial organs like liver compensate for the spleen.

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Surfaces, Borders and Ends:

Peritoneal Covering and Ligaments:

Long Axis of the Spleen: Blood Supply:

Histology of Spleen:

The spleen presents superior and inferior borders, diaphragmatic and visceral surfaces, the medial and the lateral ends with gastrosplenic and lienorenal ligaments. Diaphragmatic surface is related to diaphragm which separates it from the left pleural cavity and the 9th, 10th and the 11th ribs. Visceral surface of the spleen presents the centrally placed hilum between the superior and the inferior borders. Branches of the splenic artery enter the spleen and the tributaries of the splenic vein come out at the hilum. Just below lateral to the hilum lies the pancreatic impression for the tail of the pancreas. Between the hilum and the superior border is the gastric impression. Stomach is separated from the gastric impression not by the lesser sac but by the greater sac. Between the hilum and the inferior border lies the renal impression. Between the hilum and the lateral end is the colic impression. Superior border presents small notches in its lateral part. The medial end of the spleen is narrower and lies posteriorly near the vertebral column 3.5 cm away from the mid plane. The lateral end is broader and is placed anteriorly. The lateral end is supported by the phrenico-colic ligament. The Relations of the spleen in brief is as under: Anterior : Stomach and greater sac Posterior: Left dome of diaphragm, left pleura, 9th, 10th and 11th ribs. Inferior: Splenic flexor of the colon. Medial: Left Kidney and tail of pancreas are related to the left of the hilum. Spleen is completely covered with the peritoneum and has close relation with the diaphragm. This explains the mobility of the spleen during the movements of respiration. Spleen has two ligaments namely gastro-splenic and the lienorenal. Lienorenal ligament is the double fold of posterior extending from the hilum of the spleen to the anterior surface of the left kidney. It contains the tail of the pancreas and the spleen vessels. Gastrosplenic ligament extends from the greater curvature of the stomach to the hilum of the spleen. It contains short gastric arteries, the branches of the splenic which supply the funds of the stomach. The close friendship of the spleen with three ribs 9th, 10th, 11th is the main cause of the rupture of the spleen in fracture of the ribs. It must be remembered that it is the enlarged spleen which is more susceptible to rupture than the normal. Long axis of the spleen is along the 10th rib. Upper border of the spleen lies along the 9th while lower border along the 11th. It is supplied by the splenic artery the branch of the coliac artery. Splenic vein joins the superior mesenteric vein to form the portal vein, behind the neck of pancreas at the level of transpyloric plane (L1). Inferior mesenteric vein is the main tributary of the spleen vein behind the body of the pancreas. It presents an outer serous coat and the inner fibro-elastic coat. The outer serous coat covers the organ completely except at the hilum. Running from the fibroelastic coat are the trabeculae. In human spleen smooth muscle fibres are present in the fibroelastic coat and are found in the trabeculae. Pumping action of the spleen is mainly due to the elastic recoil of these elastic fibres. Splenic pulp is of two types, i.e. red and white. Lying in the white pulp are the Malphigian corpuscles. It consists of a collection of lymphoid tissue with a small central blood vessel. Red pulp contains red blood corpuscles, marcophages, Iymphocytes and monocytes.

Spleen Development:

Anomalies of the Spleen:

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Spleen is mesodermal in origin. It develops in the left layer of dorsal mesogastrium as small mesenchymal tubercles which join to form the mesenchymal mass. It bulges to the left of the dorsal mesogastrium. As the stomach rotates to the left spleen comes to lie on the left and omental bursa goes to the behind the stomach. Dorsal mesogastrium forms gastrosplenic and the lienorenal ligaments. Agenesis : 1. Absence of spleen, 2. Spelanculi, accessory spleens 3. Splenic cyst arises from the embryonic cell rest and are mostly dermoids. Investigations of the spleen: 1. Blood 2. Plain X-ray 3. Ultrasound 4. Colour Doppler 5. Isotope scan 6. Portal systemic venography with angiography 7. CT scan.

CLINICAL Rupture of Spleen:

Diagnosis of Splenic Rupture:

Accessory Spleens:

Ballances Sign: Absence of Colonic Resonance:

Splenic Infarction:

Spleen is the commonest abdominal organ to rupture due to blunt trauma. Splenic rupture is fatal as it causes severe haemorrage unless diagnosed and treated as an emergency. Ruptured spleen is always removed and never repaird like the liver. While doing splenectomy lienorenal ligament is opened carefully, tail of the pancreas is isolated and the splenic artery and the vein are ligated individually. 1. Four quadrant tapping of the anterior abdominal wall may show blood. 2. Plain X-ray: Plain X-ray shows the following findings in case of ruptured of spleen: 1. Absence of splenic shadow 2. Indentation of gastric shadow 3. Obliteration of left psoas shadow 4. Raised left dome of diagphragm 5. Coils of intestine filled with fluid. They are seen at the hilum of the spleen, tail of the pancreas, omentum, mesentery and even at the testis and ovary. After removal of the spleen, accessory spleens grow and the symptom of the disease for which operation has been done, starts reappearing (Thrombocytopenic purpura). Blood around the ruptured spleen clots and does not shift with the change of position of body. There is dullness around the spleen on percussion. Enlarged spleen pushes the transverse colon and left colic flexor downwards causing absence of colonic resonance over the splenic mass. It must be remembered that in retroperitoneal tumours, colon is not displaced and the colonic resonance is present. It is interesting to note that in splenic injury there is presence of dullness and absence of colonic resonance. As there is no anastomosis between the smaller branches of the splenic artery obstruction leads to infarction. It is commonly seen in sickle cell anaemia and embolic phenomenon in mitral stenosis.

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Keher’s Sign: Relation with the Tail of Pancreas: Causes of Enlargement of Spleen: Hypersplenism:

Splenic Puncture:

Palpation of Spleen: Splenic Portography:

In splenic infarction referred pain is felt in the left shoulder. During splenectomy tail of pancreas has to be separated without injuring it. I remember the saying “do not tickle the pancreas otherwise it will tickle you till death”. It is seen in malaria, typhoid, haemolytic conditions and leukaemia and the portal hypertension. Massive enlargement of spleen goes towards the right iliac fossa along with its long axis (10th rib). In this condition there is enlargement of spleen and anaemia, leucopenia, thrombocytopenia and bone marrow hyperplasia. The conditions are benefited after splenectomy. It is done through the 8th or the ninth left intercostal space in the midaxillary line. During the procedure the patient must hold breadth in full expression. It can be done for recording portal pressure. Palpation of the spleen is done in supine position and should start from the right iliac fossa towards the left sub-costal arch. The notched superior border is the important clinical sign of its identification. Splenic and portal venography is done by taking the films during venous feeling to demonstrate the site of portal block.

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LIVER Introduction:

The liver is the largest organ of the body. It is the only organ in the body which is capable of regeneration. It replaces the lost tissue completely with great rapidity making wide resection of the liver for localised tumour possible. It is also known a hepar. Liver is a wedge shaped organ situated in the upper part of the abdominal cavity under the diaphragm. It is well protected by the right subcostal arch. Its base is directed to the right and the edge to the left. It presents right lateral, anterior, posterior, superior and the inferior surfaces. It presents thin and the sharp inferior border, which can be palpated in cases of enlarged liver. Size of the liver in children is relatively larger and the palpation of the liver through the anterior abdominal wall must be considered as normal. The above mentioned anatomical fact explains the normal bulging of the abdomen in children (Figures 299 and 300).

Figure 299 Showing liver with surfaces. Please note that the relations of right lateral surfaces are divided into three zones labelled as 1, 2 and 3. (1) lung and pleural cavity, (2) pleural cavity, (3) diaphragm

Figure 300 Showing anterior surface of liver

Weight:

Shape: Appearance:

Functions:

Liver is divided into two lobes—the right and the left, by means of the line of attachment of the falciform ligament. The right lobe is larger than the left. Male: 1.4 to 1.8 kg. Female: 1.2 to 1.4 kg. Its weight is variable and ranges from 1 to 2.5 kg. It is better to remember its weight as 1.5 kg on an average. It is wedge shaped with base directed to the right and the edge to the left. Liver looks reddish brown in fresh state. It is friable, firm and pliant. After injury it bleeds profusely due to its vascularity. Though friable it can be sutured and repaired unlike the spleen which is removed when injured. It is known as the greatest chemical factory. It secrets bile and the heparin. Metabolism, of the carbohydrate, protein and the fats is done by the liver.

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Avascular Plane of Liver (Cantlie’s line) Lobes of the Liver:

Superior Surface:

Anterior Surface:

Right Lateral Surface:

Visceral Surface:

It metabolises drugs, detoxicates the toxic material including ammonia. (Deamination). In porta caval shunt blood by-passes the liver and reaches the brain causing porta systemic encephalopathy. It stores glycogen and stores vitamin B-12 for the period of three years. It produces albumen, fribronogen, prothrombin and the cholesterol. It destroyes bacterias and does all the functions of reticulo-endothelial system. It passes through the fossa for the gallbladder and the groove for the inferior vena cava. It is important plane for hepatic resection in injury or in tumours. They are right and the left. The line of demarcation is marked by the falcifarm ligament on the anterior and the superior surfaces, by the ligamentum teres hepatitis on the inferior and the ligamentum venousum on the posterior surfaces. Central part of superior surface shows a slight depression while the area on its right and left sides present bulgings. The central portion is related to the central tendon of the diaphragm which separates it from the heart and the pericardium. Laterally raised portions of this surface are in contact with right and the left domes of the diaphragm respectively. Diaphragm separate the liver from the lungs and the pleurae. It must be kept in mind that the right dome of the diaphragm is at a higher level than the left, due to large size of the right lobe. It presents line of attachment of the falciform ligament which is more to the right than the left. It has ligamentum teres hepatis at its lower free margin which represents the left obliterated umbilical vein. The anterior surface is in contact with the diaphragm. However, the lower part of the pleural extension covers the anterior surface on the right. Sharp anterior border separates the anterior surface from the inferior. The inferior border presents a notch for the gallbladder and a notch for the ligamentum teres hepatics. It runs from the left 8th cartilage to the right 9th costal cartilage across the epigastrium. Right lateral surface is related to the diaphragm which separates it from the right lung and the pleura. Upper limit of right lateral surface is related to the 7th rib and the lower lies at the level of 11th rib. Relation of the right costodiaphragmatic recesses to this surface has the clinical significance, specially in liver biopsy. Liver biopsy is done through right eighth or ninth intercostal space. Upper one-third of the surface is related to lung and pleural cavity, middle one-third is related to the pleural cavity and the lower one-third is related to the diaphragm. Biopsy needle passes through the 8th right inter-costal space traverses the pleural and the peritoneal cavities and reaches the liver. Visceral surface presents porta hepatis, fossa for the gallbladder, fissure for the ligamentum teres hepatis, groove for the inferior vena cava and the fissure for the ligamentum venosum. Impressions on the visceral surface of left lobe: 1. Shallow gastric impression. 2. Tuber omentale – lies to the left of the attachment of ligamentum venosum.

Fossa for the Gallbladder (Figures 301 to 303):

Impressions on the visceral surface of right lobe: It is the shallow pear-shaped depression which runs from the porta to the inferior border of the liver where it produces a small notch. Between the fissure for ligamentum teres on the left, fossa for the gallbladder on the right, the porta hepatis behind and the inferior border of liver in front lies

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Figure 301 Showing visceral surface of liver

Figure 302 Showing visceral surface of liver caudate and quadrate lobes

Figure 303 Showing falciform ligament of the liver

Posterior Surface (Figures 304 and 305):

the quadrate lobe of the liver. Near the impression for the neck of gallbladder there is an impression for the duodenum. Shallow colic impression is seen on the right side of the fossa for the gallbladder. Below and to the right of the impression for the duodenum lies the renal impression which is followed by colic impression. Porta hepatis gives passage to the portal vein, hepatic artery, hepatic ducts and lymph vessels. Fissure for the ligamentum venosum divides the surface into right and the left. Immediately to the left of the fissure lies the groove produced by the abdominal part of oesophagus. Between the fissure for ligamentum venosum and groove for inferior vena cava lies the caudate lobe. To the right of the groove for inferior vena cava lies the bare area of the liver bounded in front by the anterior and behind by the posterior layers of coronary ligaments. These two layers meet to form the right triangular ligament on the right side. Lower and medial part of the bare area is related to the right suprarenal gland. Lower and the left corner of the caudate lobe presents as the papillary process.

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Figure 304 Postero inferior surface of liver showing peritoneal reflection and ligament of liver

Figure 305 Postero inferior view of liver. Showing sub diaphragmatic spaces 1,2,3 on right and 4 and 5 on left

Peritoneal Reflections and Ligaments:

Supports of Liver:

True Ligaments:

False Ligaments:

Right layer of the falciform ligament after reaching the anterior and the superior surfaces of the liver, turns to the right to form the anterior layer of the coronary ligament. After forming the right triangular ligament the line of peritoneal reflection runs to the left as the posterior layer of coronary ligament. Next it passes along the groove for the inferior vena cava and turns around the caudate lobe in the fissure for ligamentum venosum. It reaches the porta hepatis and turns back to return to the fissure for the ligamentum venosum. On the right side of the porta the layer forms the free margin of the lesser omentum. Next it goes to the left to form the left triangular ligament and returns to the right to form the left layer of the falciform ligament. They are as under 1. Ligaments : They are of two types: true and the false. False ligaments are the mere folds of peritoneum, while the true ligaments are fibromuscular bands, i.e. ligamentum teres hepatis and the ligamentum venosum. 2. Surrounding viscera 3. Intra-abdominal pressure 4. The tone of the muscles of the anterior abdominal wall. 5. Hepatic veins : If the liver is separated from the diaphragm by dividing all the ligaments along with the surrounding organs, liver does not fall as it is firmly anchored to the posterior wall of the abdomen through the hepatic veins which directly open into the inferior vena cava. 1. Ligamentum teres hepatis : Runs from the umbilicus to the left extremity of the porta hepatis. It is the remnant of left umbilical vein. 2. Ligamentum venosum: It is placed in the fissure for the ligamentum venosum. It connects the inferior vena cava with the left branch of the portal vein during embryonic life. It is the remnant of ductus venous. 1. Coronary ligament: It presents anterior and posterior layers forming the anterior and posterior limits of the bare area of the liver. Posterior layer connect the liver to the diaphragm and goes anterior to the right kidney.

Liver

Peritoneal Coverings:

Porta Hepatis:

Segmental Anatomy of Liver (Figures 306 and 307):

Figure 306 Showing segments of liver seen from front

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2. Right triangular ligament: Connects the right lobe of liver to the diaphragm 3. Left triangular ligament: Connects the left lobe of the liver to diaphragm. 4. Falciform ligament (Figures 302 and 303): Falciform ligament connects the anterior and superior surfaces of liver with the anterior abdominal wall and the diaphragm. It is triangular in shape and has two layers. Its base is placed on the anterior and the superior surfaces of the liver while the apex is at the umbilicus. Its anterior margin is connected to the anterior abdominal wall approximately in the midline. Its free posterior margin runs from umbilicus to the sharp inferior border of the liver and goes to the porta hepatis. It contains ligamentum teres hepatis. It is accompanied by the paraumbilical veins, which drain blood from the area around the umbilicus into the left branch of the portal vein. In cirrhosis of liver due to increased hepatic pressure blood flow in the paraumbilical veins is reversed, as a result, radiating veins are seen going away from the umbilicus in all directions. This is known as caput medusae. Three areas of the liver are bare, i.e.: having no peritoneal covering. They are as under 1. Bare area of liver - between coronary ligaments. 2. Fossa for the gallbladder. 3. Groove for the inferior vena cava. Fibrous capsule of the liver is known as Glissons capsule. It stops at the porta hepatis and turns inwards into the substance of the liver. Branches of hepatic artery, portal vein and the hepatic ducts are seen at the porta along with the lymph nodes. The portal vein, hepatic artery and the hepatic ducts are arranged antero-posteriorly at the porta hepatic (VAD). Liver is divided into segments according to the branching pattern of the biliary, arterial and the portal systems. Liver is divided into eight segments. Each has an independent artery, bile duct, tributary of hepatic vein and the tributary of the portal vein. Segments are labelled as I to VIII. Left lobe of liver is divided into I – IV and the right from V – VIII. Intersegmental plane is marked by the hepatic veins. During segmental resection intraoperative ultrasonography forms the basis of identification of the intersegmental planes (Gouinaud’s classification of hepatic segments).

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Figure 307 Showing segments of liver

Lymphatic Drainage of the Liver: Deep Lymphatics of the Liver:

Blood Supply of Liver:

Histology (Figures 308 and 309):

Figure 308 Hepatic lobule

Lymphatic channels of liver begin in periportal spaces of Mall and most of the lymphatic drain into the thoracic duct. Superficial lymphatics go to retrosternal and mediastinal nodes. Other goes to the hepatic and paracardial, and the coelic nodes. There are two channels ascending and the descending. Ascending trunk passes through the opening for the inferior vena cava in the diaphragm and reaches nodes near the inferior vena cava. Descending trunk goes to hepatic nodes. Outstanding feature of the liver is its double blood supply which comes from the hepatic artery as well as from the portal vein. Hepatic artery supplies 20% of the blood while portal vein provides 80%. Portal vein has no valves. However, the portal vein and the 3 hepatic veins are provided with coats of smooth muscle, which helps them to control the blood flow in the liver. Pressure in the hepatic artery is 100 – 150 mm Hg, i.e. 8 - 12 mm Hg in the portal vein and 1-4 mm Hg in the hepatic veins. Methods of measuring the portal pressure are direct and the indirect. Direct by the splenic puncture which is hardly done these days. It is measured indirectly by passing a catheter into the inferior vena cava through the basalic vein of the arm (Wedged hepatic venous pressure). Patency of the portal vein and the direction of blood is obtained by Doppler Ultrasonography. Liver presents the fibrous capsule and the parenchyma. Fibrous capsule of the liver is known as Glissons capsule. Hepatic lobules are hexagonal in shape with a central vein in the centre. Running from the central vein are the cords of liver cells arranged in radiating fashion. They line the sinusoids and the capillary space between them is for biliary capillaries.

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Figure 309 Showing liver biopsy. Please note the biopsy needle passes through two cavities

Development:

Clinical: Cirrhosis:

Hydatid Cyst:

Complication:

Sinusoids are lined by Kupffer’s cells. Small branches of the portal vein open into hepatic sinusoids which go towards the central vein. Blood is collected from the central veins by the hepatic veins which open into the inferior vena cava. Situated in between the hepatic lobules is the portal traid (portal canal) which contains branch of portal vein, biliary duct and the sub-hepatic vein. Periportal space is known as a space of Mall and perisinusoidal space is known as space of Discii. Liver is endodermal in origin and develops from the caudal part of foregut in the form of hepatobiliary bud. Hepatic bud is cranial and the biliary caudal. Hepatic bud develops under the septum transversum and forms the liver. The biliary bud which is placed caudally under the liver forms the gallbladder. Endoderm forms the parenchymal tissues while the mesoderm forms the capsule. Liver is well protected by right subcostal arch. In case of injury, being friable it is torned easily and bleeds profusely. It is sutured and repaired. At times its partial resection is done. Liver is never removed like the spleen. Alcoholic abuse and viral hepatitis are the common causes of cirrhosis of liver. Hepatic cell death (necrosis) followed by fibrosis and regeneration result in formation of nodules. Intrahepatic connections develop between the portal vein and the hepatic arterial radicals. Artery resists pressure and continues to supply blood to the liver. Liver becomes dependent for blood supply on the hepatic artery. Hepatic artery makes a despirate attempt and communicates with portal vein. It leads to the formation of the intrahepatic shunts. It is followed by development of extrahepatic shunts such as at the lower end of the oesophagus. Here the communication between the left gastric vein and the hemiazygos vein forms porta systemic anastomosis. In injury of the liver the bleeding can be arrested by compressing the hepatic artery in the free margin of the lesser omentum between the thumb and the index (Pringle’s maneuver). Larva of Echinococcus granulosus enter the right lobe of the liver through the radicals of the portal vein. Ova enters the liver and forms the hydatid cyst in the liver. It has 3 layers 1) adventatia 2) laminated membrane 3)germinal epithelium with hydatid fluid. Patient may present with swelling in the upper abdomen. Investigations like plain X-ray, ultrasound, CT scan and ERCP can be done. Hydatid cyst may rupture in the peritoneal cavity, pleural cavity and alimentary canal. Jaundice appears due to compression of the biliary ducts.

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Accidental Ligation of Hepatic Artery:

Hepatitis:

Carcinoma of Liver: Primary Carcinoma of Liver:

Secondary carcinoma:

Secondary Carcinoid: Amoebic Liver Abscess:

Rupture in the peritoneal cavity is associated shock. Accidental ligation of the hepatic artery does not lead to hepatic failure as only 20% of the blood supply of the liver comes from the hepatic artery and 80% from the portal vein. If the common hepatic artery is ligated proximal to the origin of the right gastric artery collateral circulation through the gastric and gastro-epiploic arteries opens. Hepatitis is mainly due to alcoholic abuse, malnutrition and viral hepatitis. Viral hepatitis is of two types namely A and the B. Hepatitis A is due to contamination of water and hepatitis B is due to the injection with contaminated needles. Liver cells undergo necrosis, fibrosis and regeneration. It obstructs the portal blood flow leading to portal hypertension. Besophageal varices develop at the lower end of the oesophagus. It leads to vomiting of blood. (Haematemesis). Oesophageal varices can be diagnosed by the barium X-ray which shows typical cotton wool appearance. Endoscopic examination of the lower end of oesophagus is preferred. Oesophageal varices can be injected with sclerosent on two to three occasions. The varices can be ligated endoscopically by application of bands. Carcinoma of liver can be primary and the secondary. The 80% of the primary carcinoma of liver is the hepatocarcinoma. (Hepatoma). It is an end result of the cirrhosis of liver. The clinical features of the hepatoma of liver can be remembered as five “As.” 1. A - Anaemia 2. A - Abdominal mass 3. A - Ascites 4. A - Asthenia (muscular weakness). 5. A - Alfa foeto-protein is present. Alfa foeto-protein is a normal constituent of the plasma of foetus after 6 weeks and it disappears at birth. Liver is the commonest site for the malignant metastasis from cancer of the gastrointestinal tract through the portal vein. Cancer of the breast and the cancer of the pelvic organ also reach the liver. When secondaries are in the liver, loss of weight, loss of appetite and increased level of alfa foeto-protein are diagnotic of liver involvement. In late cases growth invades portal and the hepatic veins causing their thrombosis. Treatment carcinoma liver 1. Chemotherapy 2. Thrombolization of the vessels supplying tumour 3. Partial/segmental hepatectomy 4. In in-operable cases soratebin Nexavar and new drug has been tried with fair success. Malignant carcinoid gets metastasised in the liver. The site of the carcinoid is an appendix. It is accompanied by vasomotor phenomina nd pulmonary stenosis. Amoebic dysentery is caused by Entamoeba histolytica. Amoebic liver abscess is the complication of amoebic dysentery. Amoebae reach the right lobe of liver through the tributaries of the portal vein. They establish their colony at the expense of liver tissue which gets liquified and an abscess is formed. It has a typical colour known as anchovy sauce. If neglected it can rupture into the peritoneal cavity, pleural cavity, outside, under the skin and even into the lung. Bursting of the amoebic abscess

Liver

Development of Liver:

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into the lung almost amounts to cure as the pus is out in the form of expectoration. Physical signs of amoebic abscess seen on the right: 1. Collapsed lung 2. Pleural effusion 3. Raised and fixed diaphragm 4. Maximum tenderness at the site of abscess 5. Displacement of the liver downwards. Liver is endodermal in origin and develops from the hepato-biliary diverticulum at caudal end of the fore-gut. Hepatic bud is cranial and biliary bud is caudal. It is the hepatic bud which forms the liver under the septum transversum.

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GALLBLADDER Functions of Gallbladder:

Figure 310 Showing gallbladder and its ducts

Figure 311 Showing course and relations of the common bile duct

It is the pear-shaped organ situated in the fossa for the gallbladder, on the visceral surface of the liver. 1. Storage 2. Concentration of bile 3. Secretion of mucous 4. Controls pressure in biliary system by concentration and dilatation with the help of cholecytokinin secreted by the duodenal mucosa. Note on concentration of bile: Bile is 5-10 times concentrated due to absorption of water. Bile salt is a solvent for cholesterol. In inflammation of gallbladder bile salt alone are absorbed. Superior surface is in direct contact with liver and has no peritoneal covering. Its inferior surface is related to the first and the second parts of the duodenum and has peritoneal covering. Fundus of the gallbladder projects beyond the inferior border of the liver has the peritoneal covering on all the sides (Figure 310 and 311).

Gallbladder

Cystic Duct:

Common Bile Duct:

Blood Supply:

Structure of the Gallbladder:

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Capacity of gallbladder is 30-50 ml equal to the capacity of newborn stomach. Gallbladder is divided into three parts—fundus, body and the neck. Fundus projects anteriorly beyond the inferior margin of the liver and touches the anterior wall at the tip of the right ninth costal cartilage. The body of the gallbladder lies between the fundus and the neck. Cystic duct begins from the neck and joins the common hepatic duct to form the common bile duct. The long axis of the gallbladder is directed forwards, downwards and slightly to right from the porta to the inferior border of the liver. The pressure on the tip of the 9th right costal cartilage gives pain in inflammatory conditions of the gallbladder, i.e. cholecystitis (Murphy’s sign). Neck of the gallbladder is directed upwards, forwards backwards and downwards. It is continuous with the cystic duct. Cystic artery is intimately related to the neck of gallbladder. At the junction of neck and the cystic duct there is a constriction. Distal part of the neck, forms a small pouch. It is known as Hartmann’s pouch. It is said to be created by a stone and is not considered as the normal part of the organ. Mucous membrane of the interior of the neck forms spiral valve. It is a two lane high-way, e.g. bile enters the gallbladder through the cystic duct and leaves the gallbladder as concentrated bile through the cystic duct. It is approximaterly 4 cm in length. It runs from the neck of gallbladder to the left side to join the common hepatic duct to form the common bile duct. Union of cystic duct with common hepatic duct at times may lie at the lower level. Interior of the cystic duct presents cresentic folds of mucous membrane. They are half to one dozen and is from the spiral valve of Heister. It is divided into four parts. 1. Supraduodenal 2. Retroduodenal 3. Infraduodenal 4. Intraduodenal It is 7 cm in length and is formed by the union of cystic and common hepatic ducts. It runs in the free margin of the lesser omentum where the portal vein lies behind and the hepatic artery to the left. It has “already been stated that the free margin of the lesser omentum forms the anterior boundary of the foramen of Winslow (Aditus to lesser sac). The above description relates to its supraduodenal course. During its second phase it passes behind the first part of the duodenum with the gastroduodenaI artery on its left. In its third phase it lies behind the head of the pancreas. Sometimes the duct is completely embedded in the substance of pancreas. During this course it runs downwards and to the right to open on the posteromedial part of the second part the duodenum along with the pancreatic duct. Inferior vena cava lies posterior to the head of the pancreas along with renal veins. Gallbladder is supplied by cystic artery the branch of the right hepatic. Gallbladder may get an accessory branch from the gastroduodenal artery. At times the right hepatic artery crosses in front of the common hepatic duct, by taking a tourtous course. Tortuosity of the hepatic artery is known as caterpillar turn or Moynihan: hump. Cystic vein joins the portal vein. It presents three coats, i.e. serous, fibromascular and the mucous. Mucous surface presents small pits which dip into the fibromascular coat. They are known as crypts of Luschka. Mucous membrane does not contain glands. Epithelium of the mucous membrane is of tall columnar variety.

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Cholecystography:

It is of two types, namely the oral and intravenous. (Dye for oral use is telepaque and dye for intravenous cholecystography is Biligrafin). It is a special radiological investigation for the visualisation of the gallbladder. A special dye is given either orally or intravenously which is secreted by the liver. As the dye reaches the gallbladder, it is concentrated and helps in visualization of the gallbladder. Folded fundus is due to failure of canalisation of the part of fundus, and is known as Phrygian cap. Phrygian cap can be mistaken for pathological deformity of the organ. Phrygian cap is a hat worn by the people of Phrygia, an ancient country of Asia minor. Investigations for the diseases of the gallbladder: 1. Plain X-ray 2. Cholecystography – oral IV, porcelain. 3. Ultrasound–It shows stones, thickness of wall of gallbladder and growths. 4. CT scan 5. Per cutaneous transhepatic cholangiography 6. Radio-isotopes scan 7. Endoscopic retrograde cholangiopancreatography (ERCP) 8. Per-operative cholangiography. 9. Postoperative cholangiograpy. 10. MRCP (Magnetic resonance cholangiopancreatography). This procedure does not require dye.

CLINICAL Cholecystis :

Murphy’s Sign: Gallstone: (Cholelithiasis):

It is accompanied by severe pain radiating to the inferior angle of scapula of the right side. There is referred pain in the right shoulder as the fibers of the right phrenic nerve supplies the diaphragm. Root value of phrenic nerve is cervical 3, 4 and 5 while the root value of the supraclavicular nerves is cervical 3 and 4. Right phrenic nerve supplies the gallbladder through the ciliac ganglion. Pressure of the tip of the 9th costal cartilage gives pain due to inflamed fundus of the gallbladder. It is known as Murphy’s sign. 1. Gallstone is the common cause of biliary cholic. Stone can obstruct the common bile duct and leads to surgical jaundice. It can perforate and enter the duodenum and the transverse colon. The stone can cause duodenal obstruction and the obstruction of the colon is possible only in the presence of carcinoma of colon. 2. Uneventful gallbladder surgery is possible only if the surgeon identifies three ducts and three arteries clearly. Three ducts are, common hepatic duct, cystic duct and the common bile duct. Three arteries are hepatic, right branch of hepatic and cystic. Identification of the duct during surgery is confirmed by presence of bile on aspiration. 3. Bleeding during surgery of gallbladder can be controlled by the compression of hepatic artery which gives cystic branch. The hepatic artery is compressed in the free margin of the lesser omentum with index and the thumb. 4. Even if the cystic artery is ligated the gallbladder does not go gangrenous as it has alternate blood supply from the liver bed. 5. Gangrene of the gallbladder can occur due to its rotation as a result of long mesentry.

Gallbladder

Aid to Memory:

Choledocal Cyst:

Courvoisier’s Law:

Callot’s Triangle (Figure 312):

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6. Gallstone from the supraduodenal part of the common bile duct can be removed by opening the duct. However, exposure of the common bile duct and the pancreatic duct can be done by Kocher’s method. An incision is given along the right side of the second part of the duodenum and the duodenum with the head of pancreas are mobilised to the left. Gallstones are common in female. Please remember 5 ‘F’ which favours formation of gallstone 1. F - Female 2. F - Fifty 3. F - Fatty 4. F - Fertile 5. F - Flatulant It is the fusiform dilatation of the common bile duct due to congenital weakness of the muscles of the duct. It may contain 1 to 1.5 ltr of bile and can produce symptoms of obstructive jaundice with fever. At times it may go malignant. Due to recurrent obstruction by stone the gallbladder gets chronically inflamed and contracted and is not palpable. However in the carcinoma of the head of the pancreas the obstruction being acute and sustained, the gallbladder is distended and palpable. Callot’s triangle is situated below the visceral surface of the liver and is an important landmark for localization of the cystic artery, which lies in the triangle along with the gland of Lund. It is bounded by liver above, common hepatic duct on the left and the cystic duct on the right.

Figure 312 Showing triangle of Collot

Carcinoma of Gallbladder:

Carcinoma of the Common Bile Duct: Saint’s Triad: Development of Gallbladder:

Carcinoma of gallbladder is common in female and 90% cases are associated with gallstones. It is common in some parts of India. It directly spreads to the liver and the porta hepatic as gallbladder is directly related to the under surface of the liver in the fossa for the gallbladder with no peritoneal intervention along with the resection of the underlying part of the liver is mandatory. Incidence of the carcinoma of the common bile duct is more than the carcinoma of the gallbladder and is associated with gallstone in 30% of cases. In carcinoma of the lower third of the common bile duct, duodenum along with the head of the pancreas are removed (Wipples operation). Gallstones, hiatus hernia and the diverticulosis of the colon are present in the triad. Clinician has to sort out the exact cause of the symptoms. Gallbladder is endodermal in origin and develops at the caudal end of the foregut in the form of hepatobiliary diverticulum. The hepatid diverticulum is cranial and the biliary diverticulum is caudal. Biliary diverticulum forms the gallbladder.

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Anomalies of Gallbladder:

They are under: 1. Agenesis of gallbladder 2. Double gallbladder: One may lie inside the substance of the liver (Intrahepatic). It must be remembered that in early embryonic period gallbladder intra-hepatic 3. Septate gallbladder 4. Hanging gallbladder—It has a long mesentery and as a result can undergo rotation causing gangrane of the organ. 5. Hartman’s pouch. If a dilatation at the neck of gallbladder. It is pathological due to stone rather than congenital. 6. Cystohepatic duct—It runs from the liver to the gallbladder. Postoperative leakage of bile after cholecystomy leads to fall of blood pressure. (Waltman-Walter’s syndrome). Hence keeping of a drainage tube is mandatory. 7. Accessory cystic duct — duct of Luschka. 8. Low insertion of cystic duct into the common bile duct just proximal to duodenal sphincter. Dictum is not to dissect cystic duct with a fear of damaging the blood supply of common bile duct invariably resulting in stricture. 9. Phrygian cap: It is due to non-calisation of the fundus of the gallbladder. 10. Diverticulosis of gallbladder Note: Intra and extrabiliary channels are with lumen which get obliterated due to hyperplasia of luminal cell. The channels get recanalised allowing bile to flow. Non-canalisation leads to atresia.

Duodenum

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DUODENUM Duodenum is a Latin word which means organ having width of 12 fingers. Duodenum is the first part of the small intestine which is shortest, widest and fixed. It is retro-peritoneal except for its proximal 2.5 cm and has the length of 25 cm. Duodenum begins at the pylorus of the stomach and ends at the duodeno-jejunal flexor. It has “C” shaped curvature which clasps the head of the pancreas. Proximal 2-5 cm is mobile due to the peritoneal covering on all the sides. Duodenum is due to the extension of the lesser and the greater omentas. Duodenum is fixed to the posterior abdominal wall to falicitate the functions of the common bile duct and the pancreatic duct by preventing their distortion. As the chyme comes in contact with duodenum mucosa release cholecystokinin and the secretin. Duodenum has four parts, the first is 5 cm, second 7.5 cm, the third 10 cm and the fourth is 2.5 cm in length. Second part of the duodenum is placed at the posterior plane as the duodenum is moulded against the vertebral column. Second part of the duodenum forms an important region as it is the meeting point of the common bile and the pancreatic ducts. First part of the duodenum lies at the level of first lumbar vertebra and the third part of the duodenum lies at the level of third lumbar vertebra (Figure 313). Figure 313 Showing parts of duodenum, pancreas and branches of coeliac artery

Peritoneal Relation: First Part of the Duodenum:

Relation with Peritoneum:

Proximal 2.5 cm is covered with the peritoneum from all the sides as the lesser and the greater omenta extend to the right along the upper and lower borders of the proximal part of the duodenum. First part is 5 cm in length. It runs from the pylorus, to the right, upwards and backwards to reach the neck of gallbladder where the first part ends and the second begins. The junction of the first and the second is stained with bile due to the relation with the neck of the gallbladder. Proximal 2.5 cm is covered with the peritoneum due to the attachments of the lesser and greater omenta. This grants mobility to the proximal half of the duodenum. It forms the anterior relation of the head of the pancreas. In the barium meal study of the stomach and the duodenum the proximal 2.5 cm part of the duodenum forms the triangular duodenal cap which is smooth mobile the base being directed to the left.

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RELATIONS OF FIRST PART OF DUODENUM Superior:

First part of the duodenum is related to the aditus to the lesser sac with its free margin containing portal vein, common bile duct and the hepatic artery. Inferior: Head of the pancreas. Anterior: It is related with the quadrate lobe of liver and the gallbladder.

Second Part of Duodenum :

Posterior : Head of the pancreas, common bile duct, gastro-duodenal artery, portal vein and the inferior vena cava form the posterior relations. It is 7.5 inches in length. It begins at the neck of gallbladder runs vertically downwards to end at the level of the lower border of the third lumbar vertebra, and turns to the left as the third part.

RELATIONS OF THE SECOND PART Posterior Relations (Figure 314):

Hilum of right kidney, right ureter, right renal artery, vein right psoas major muscle with psoas fascia are the posterior relations. Posterior relations of the second part of duodenum can be remembered as follows: Second part of duodenum lies on the hilum of the right kidney. The hilum lies on right psoas major and itself contains right renal vein, right renal artery and the pelvis of right ureter antero-posteriorly.

Figure 314 Showing posterior relations of 2nd part of duodenum

Anterior Relations (Figure 315):

Figure 315 Showing anterior relations of second part of duodenum

Transverse colon crosses the second part of duodenum from the front without peritoneal intervention. Liver and gallbladder are related to supracolic part of the duodenum, and infracolic part is related to the coils of the small intestine. Anteriorly the supracolic and the infracolic parts of the duodenum are covered with peritoneum.

Duodenum Medial Relations: Lateral Relations: Ampulla of Vater:

Third Part of the Duodenum (Figure 316):

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Head of pancreas, common bile duct, pancreatic duct, anastomosis between superior and inferior pancreatico-duodenal arteries are medial relations. The right lobe of liver, right colic flexure and the ascending colon form the lateral relations. The common bile and the pancreatic ducts pierce the posteromedial aspect of the second part of duodenum together and form the dilation known as the ampulla of Vater. The ampulla opens in the second part of the duodenum over the duodenal papilla. Accessory pancreatic duct enters the lumen of duodenum, some distance proximal to the duodenal papilla. The ampulla of Vater is surrounded by a smooth muscle sphincter known as the sphincter of Oddi. Third part begins where the 2nd part ends, and runs horizontally to the left. Its length is variable (7 to 10 cm). Before studying the details, the following observation may be kept in mind. This will certainly help in memorising the third part’s peculiar association with the figure of “3”.

Figure 316 Showing posterior relations of 3rd part of duodenum

1. 2. 3. 4.

Posterior Relations of the Third Part : Anterior Relations of the Third Part : Fourth Part :

is the 3rd part of duodenum. lies at the 3rd lumbar vertebra. is approximately three inches in length lies anterior to the origin of the artery of the third part of the gut, i.e. inferior mesenteric. Third part of the duodenum is sandwitched between the superior and the inferior mesenteric arteries. However, the vascular nut crackers is actually formed by the superior mesenteric artery and the abdominal aorta. Arterial compression may lead to duodenal obstruction in adults. Right psoas, right ureter, right testicular or ovarian vessels, inferior vena cava, abdominal aorta, the origin of inferior mesenteric artery, form the posterior relations. Coils of intestine, root of mesentery with superior mesenteric vessels. Superior relations: Head of the pancreas with the uncinate process. Inferior relations : Coils of small intestine (jejunum). It is 2.5 to 5 cm in length. It begins where the 3rd part ends (3rd part commonly ends at the left edge of the abdominal aorta). Thereafter it ascends upwards and to the left to duodeno-jejunal flexure which lies at the level of “2nd lumbar vertebra. It turns anteriorly, to join the jejunum and thus presents an appearance of a bent thumb. The duojejunal flexure is held in position by the suspensory ligament of Tritz, which runs from the right crus of diaphragm to the flexure. Ligaments of Tritz contains the fibrous band in the middle and striated muscle above and the smooth muscle below. The fibrous band surrounds the coeliac trunk.

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Relations of the Fourth Part (Figure 317):

Posterior: Left psoas, left sympathetic chain, left renal and testicular or ovarian vessels and the inferior mesenteric vein form the posterior relations.

Figure 317 Showing anterior relations of 3rd part of duodenum

Anterior : Root of mesentery and coils of small intestine, transverse colon and mesocolon. Right: Vertebral column.

Radiological Appearance:

Blood Supply of Duodenum:

Left: Coils of small intestine, left kidney and the left ureter are on the left of it. The proximal portion of the first part of the duodenum gives a smooth triangular shadow known as duodenal cap. It is mobile due to its complete peritoneal covering. Base of the triangle is directed to the left and apex to the right. Due to the absence of circular folds in the proximal part of duodenum the margins of the duodenal cap appear smooth. Proximal part of the duodenum is kept patent due to the protrusion of the pylorus into the duodenum similar to the protrusion of the cervix into the vagina. The proximal half of duodenum is supplied by coelic artery, the artery of the foregut and the distal half by the superior mesenteric the artery of the midgut. First part of the duodenum is supplied by the three arteries namely (1) Supraduodenal, (2) Infraduodenal, and (3) the retroduodenal. Supraduodenal is the branch of gastroduodenal. It is known as the artery of Wilke. Thrombosis of the supra-duodenal artery of the Wilke leads to the Curling’s ulcer in burns which may cause by severe bleeding. Second part of duodenum has good blood supply through the superior pancreaticoduodenal, a branch of gastroduodenal and the inferior pancreaticoduodenal artery the branch of superior mesenteric artery. Third and the fourth parts are supplied by the branches of superior mesenteric artery. Veins: Veins drain into the splenic, superior mesenteric and the portal veins.

Histology: Lymphatics:

Nerves: Sympathetic supply comes from the coeliac and superior mesenteric plexuses, segmental innervation being from T6 to T8. Parasympathetic supply is from the vagus nerves. It presents duodenal glands which lie below the muscularis mucosae (Brunner’s gland). They are arranged in anterior and the posterior groups. The lymph vessels go to the pancreatico-duodenal, the pyloric and finally reach the celiac group of nodes.

Duodenum Peritoneal Recess of Duodenum:

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They are important as they can form the sites for internal herniation leading to obstruction and strangulation of the gut. They are 6 in numbers: 1. Superior duodenal recess 2. Inferior duodenum recess 3. Retroduodenum recess 4. Paraduodenal recess, and 5. The duodenum jejunal recess. 6. Mesenterico-parietal fossa of Waldyer, which lies behind the 3rd part of the duodenum (Figure 318).

Figure 318 Showing duodenal recesses

Histology of Duodenum:

Clinical :

While releasing the strangulated loop of intestine from the paraduodenum recess inferior mesenteric vein in the free fold of the paraduodenal recess is in danger (vascular fold of paraduodenal recess). 7. Superduodenal recess: It is situated above the duodeno jejunum junction at the level of 2nd lumbar. It is guarded by superior duodenal fold. Interior mesentery vein passes behind the left end of the super duodenal fold. Its opening looks downwards. 8. Inferior duodenal recess: It lies below the duodenal jujunum junction. It is guarded by inferior duodenal fold. 9. Paraduodenal recess: It is on the left side of the 4th part of the duodenum. It is guarded by anterior vascular fold known as paraduodenal fold which contains the inferior mesenteric vein and the ascending branch of the left colic artery. It has six layers: 1. Inner-mucous membrane shows Villi with micro villi and crypts of Lieberkuhn. 2. Muscularis mucosae. 3. Submucosa-It has duodenal glands known as Brunner’s glands which are below the muscularis mucosae. 4. Circular muscle coat 5. Longitudinal muscle coat 6. Serous coat. Note: G-cell which form Gastrinoma arise from Brunner’s gland. First part of the duodenum is the commonest site of the ulcer being the first to welcome incoming acid from stomach and also has relatively less blood supply.

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Carcinoma of the Duodenum :

Annular Pancreas:

Congenital Obstruction of the Duodenum:

Peritoneum of the Duodenum:

Ulcer on the anterior duodenal wall usually perforates and the ulcer on the posterior wall usually erodes the gastro-duodenal artery and bleeds. In the perforation of the posterior wall ulcer, contents of the stomach collect in the hepato-renal pouch. Perforation of anterior wall ulcer leads to peritonitis. Adenocarcinoma which develops in the periampullary region obstructs the common bile duct resulting in surgical jaundice. In carcinoma of the duodenum, the head of the pancreas is removed along with the duodenum and in the carcinoma of the head of pancreas, the duodenum is also removed. It is the greatest example of friendship and the sacrifice on the posterior abdominal wall. Removal of the duodenum and the head of the pancreas together is known as pancreatico-duodenectomy (Wipple’s operation). Ventral pancreatic bud is bilobed. Normally they fuse to form a single mass. Two buds grow separately in the opposite direction and join the dorsal pancreatic bud, after surrounding the second part of duodenum forming a complete collar of pancreas, e.g. annular pancreas. This may produce duodenal obstruction by itself or may be associated with duodenal stenosis. Duodenum is endodermal in origin. Its proximal half develops from the foregut and the distal from the midgut. In the second month of intrauterine life due to proliferation of cells duodenal lumen gets obliterated. It gets recanalised in the third month of intrauterine life. Partial recanalisation leads to duodenal stenosis and complete failure of recanalisation leads to duodenal atresia. At times a complete septum obstructs the second part of the duodenum. Infant vomits bile right from the time of birth and losses weight. This congenital defect requires urgent surgical correction by doing duodeno-jejunostomy. It must be remembered that in congenital pyloric stenosis bile is absent in the vomitus. During development, duodenum is attached to the dorsal abdominal wall by means of dorsal mesentery. Due to the rotation duodenal loop falls back and its dorsal mesentery fuses with the parietal peritoneum and disappears (zygosis). It loses its mesentery and becomes retroperitoneal.

Pancreas

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PANCREAS It is an exocrine as well as an endocrine organ situated retroperitoneally across the vertebral column extending from ‘C’ curvature of duodenum on the right to the hilum of spleen on the left. It has head, neck, body and the tail. From the lower and the left part of the head arises the look like process the uncinate process (Figures 319 to 321). Figure of 8 has a peculiar affinity for the pancreas. Figure 319 Showing relations of pancreas

Figure 320 Showing parts of duodenum, pancreas and branches of coeliac artery

Head (Figure 321): Posterior Relations of Head of Pancreas:

1. The word pancreas has 8 alphabets. 2. Weight of pancreas is 80 gm. 3. Length of the pancreas is 8" (20 cm). 4. pH of the pancreatic juice is 8. 5. Total secretion of pancreas is approximately 800 cc. Head of the pancreas is of paramount surgical importance as it forms the key board along with duodenum on the posterior abdominal wall. Inferior vena cava, renal veins, right renal artery and sympathetic chain, common bile duct and diaphragm form the posterior relations.

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Figure 321 Posterior relations of head of pancreas (diagrammatic)

Posterior Relations of the Uncinate Process: Anterior Relations of the Head Proper: Anterior Relations of the Uncinate Process:

Neck :

Body (Figure 322):

Abdominal aorta lies behind the uncinate process.

The proximal part of the first part duodenum, transverse colon and coils of small intestine form the anterior relations of the head of pancreas. Superior mesenteric vessels are in front of the uncinate process. N. B. : Sometimes the part of the head is actually embedded in the duodenal wall Borders of the head are related to the concavity of the duodenum. The groove between the two is occupied by the anastomosis formed by superior and inferior pancreatico duodenal arteries. Gastro-duodenal artery marks the limit of the head and the neck of the pancreas anteriorly. Portal vein is formed by the union of the superior mesenteric and splenic veins behind the neck of pancreas at the level of 2nd lumbar. It lies between the neck and the tail. It is triangular in section. It presents anterior, posterior, inferior surfaces and the superior, antero-inferior and postero-inferior borders.

Figure 322 Showing head of pancreas surrounded by C shaped curvature of duodenum on right and tail touching the hilum of spleen to left

RELATIONS OF THE BODY OF PANCREAS Posterior (Figure 323):

1. 2. 3. 4. 5. 6.

Abdominal aorta, Origin of superior mesentery artery. Diaphragm The left suprarenal, Left kidney at its hilum separated by the perineal fascia. The splenic vein.

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Splenic artery runs a wavy course along the upper border of the body of the pancreas. Upper border presents the omental tuberosity. Lower border (antero-inferior border) of the body gives attachment to the transverse mesocolon. Interior surface is related to coils of intestine and the duodeono-jejunal flexure. Figure 323 Showing posterior relations of body of pancreas (diagrammatic)

Anterior Surface:

Relations of Inferior Surface: Tail : Ducts of the Pancreas (Figure 324):

Anterior surface is related to stomach, separated from it by cavity of the lesser sac. It forms part of the ‘Stomach bed’. In acute pancreatic, haemorrhagic fluid collects in the lesser sac and the foramen of Winslow gets closed, forming the pseudopancreatic cyst. This is covered with the peritoneum and is related to coils of intestine and the duodeno-jejunal flexure. It lies in the lieno-renal ligament along with the splenic vessels and touches visceral surface of the spleen near the lateral end of the hilum. It begins at the tail as small channel and increases in size as it is joined by number of tributaries on its way through the body, neck and the head. It opens into the second part of the duodenum at the duodenal papilla. (Wirsung). Lower part of the head and the uncinate process is drained by the accessory pancreatic duct. It opens into the second part of the duodenum well above the opening of the main duct. (Santorini)

Figure 324 Opening of common and the pancreatic ducts

Blood Supply:

Venous Drainage:

Lymphatic Drainage: Histology of Pancreas:

Superior and inferior pancreatico-duodenal arteries supply the head. Body gets its blood supply from the splenic artery. Its large branch to the body of the pancreas, is known as pancreaticamagna. Venous blood from the head and the neck goes to the portal vein. Blood from the body and the tail drains into the splenic vein, which is joined by the superior mesenteric vein to form the portal vein of the neck of pancreas. Lymph channels follow the blood vessels in general and go to the coeliac group of nodes after reaching the superior pancreatico-duodenal group of lymphnodes and the superior mesenteric group of lymph node. It has a definite capsule from which fibrous septae run inside to divide the organ into small lobules. Each lobule consists of a termination of main duct and alveoli. Alveoli are tubular and convoluted. Alveoli are lined with tall columnar cells which present a outer and inner zones. Outer zone is darkly stained and the inner one, is light in colour. Lying in between the alveoli are the clusters of polyhedral cells known as islets of Langerhans. They consists of A and B type of cells. ‘0’ type has also been described. Islets are richly supplied with small capillary like blood vessels. ‘A’ cells secrete glucagon and ‘B’ cells secrete insulin.

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Development :

It is endodermal in origin. It develops from the caudal end of the foregut in the form of dorsal and ventral buds. Dorsal bud gives rise to the tail, body and the upper part of the head. Ventral bud gives rise to the rest of the head and the uncinate process.

CLINICAL Acute Pancreatitis:

Autodigestion of pancreas by its own enzymes causes necrosis, oedema and haemorhages. Acute pancreatitis can also be caused by natural or iterogenic trauma (Surgical) truma. 50% cases of acute pancreatitis are having gallstones. Simple ligation of the pancreatic duct does not lead to pancreatitis as for activation of enzymes duodenal juice is required. When the sphincter of oddi is damaged due to gallstone, duodenal pressure rises and the duodenal juice enters the pancreatic duct triggering the activation of enzymes which leads to actue pancreatitis. Note : In perforated gastric ulcers on the posterior wall of the stomach the contents overflows and gets collected in the lesser sac. Due to retroperitoneal hemorrhage in pancreatitis blood travels to the Grey Turner’s flanks and produce discolouration of the skin. Sign: In surgical treatment of chronic pancreatitis 90% of the pancreas is Chronic removed except the rim near the duodenum. Excision of the large part of Pancreatitis: the pancreas leads to malnutrition due to inadequate and poor quality of the pancreatic juice. Annular Pancreas: Ventral pancreatic bud encircles the second part of the duodenum and fuses with the dorsal bud. It may be associated with duodenal stenosis which may cause duodenal obstruction. A complete septum in the second part of the duodenum gives double bubble appearance in plain X-ray or ultrasound. Air bubbles are seen in fundus of stomach and in the first part of the duodenum are seen. The condition requires urgent surgery where the duodenum is anastomosed to the jejunum. It compresses the common bile duct and cause surgical jaundice, as the Carcinoma of the common bile duct forms the immediate posterior relation of the head of Head of the pancreas. At times the pancreatic tissue is embedded in the duodenal Pancreas: wall. Growth at the neck of the pancreas obstructs the portal vein and may end in ascities of recent origin. Cancer of the head of pancreas may obstruct the interior vena cava. Radiological Study: It shows widening of the duodenal loop. (PAD sign). Pseudo-pancreatic It is not a true cyst. Pancreas forms the part of the stomach bed. It is separated from the stomach by the lesser sac of the peritoneum. In acute Cyst : pancreatitis hemorrhagic fluid collects in the lesser sac. Foramen of Winslow gets closed due to inflammatory adhesions. It presents as the large globular swelling in the epigastric region. It is treated by making an opening between the stomach and the cyst (cystogatostomy). Zollinger-Ellison In this condition there are recurrent, repeated, multiple ulcerations at the Syndrome: unusual site. They are of two types. (1) G-cells produce gastrin leading to ulceration. It can be treated by partial removal of stomach. (2) Ulcerogenic non-beta cells of tumours of islets of Langerhans’. Zollinger Ellison syndrome’s treatment is gastrectomy, however due coming up of the proton pump inhibitors like omeprazole it can be treated medically.

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PLAIN X-RAY OF ABDOMEN IN ACUTE PANCREATITIS 1. Sentinel loop: Duodenum loop gets dilated around the head of pancreas 2. Stu/Art sign. Due spasm of the transverse colon there is absence of gas in the whole of the transverse colon. This is known as Stu/Art sign. Absence of gas in right half of the transverse colon is known as Stu Sign and absence of gas in the left half of the colon is known as Art sign.

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PORTAL VEIN When blood passes through two systems of capillaries, is known as portal circulation. Portal vein drains blood from the alimentary canal excluding the lower half of the anus. It is formed like the vein, but divides like an artery. Its length is 8 cm. Normal portal pressure is 5-15 mm Hg, e.g. more that the system venous pressure. Portal vein does not have valves. Portal vein is formed by the union of superior mesenteric and the splenic veins behind the neck of pancreas at the second lumbar level. It runs upwards and to the right behind the neck of pancreas, first part of duodenum and enters the free margin of the lesser omentum. Behind the first part of duodenum, it is related to the common bile duct and the gastroduodenal artery, bile duct being on the right and the gastroduodenal artery on the left. Portal vein lies posterior to the common bile duct and the hepatic artery in the free margin of the lesser omentum. Free margin of the lesser omentum forms the anterior limit of the foramen of Winslow. Near the porta hepatis the portal vein divides into two branches namely, the right and the left. Right branch is shorter and broader while the left is narrower and longer almost like a thumb and index finger of the right hand seen from the dorsum. Right branch indicates the thumb and the left indicates the index. Near the porta the vein is related to the lymph nodes. Cystic vein joins the right branch of the portal vein before its entry into the right lobe of the liver. Left branch of the portal vein enters the left lobe of the liver. It receives the ligamentum teres hepatis along with paraumbilical veins and is connected with the ligamentum venosum (Figure 325). Figure 325 Showing portal vein

Portal Vein Tributaries:

Portal and Systemic Anastomosis:

Splenic Vein:

Inferior Mesenteric Vein:

Superior Mesenteric Vein :

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1. Splenic and superior mesenteric veins, unite to the form portal vein. 2. Left gastric: It follows the lesser curvature of the stomach and as it reaches the lower end of the oesophagus where the oesophageal veins join the left gastric vein. It finally turns to the right and join the portal vein. Left gastric vein anastomoses the hemiazygos vein, which is a systemic vein. It forms porta-systemic anastomosis at the lower end of the oesophagus. In portal hypertension these vein elongate, dialate and becomes tortuous (varicose vein). Rupture of the oesophageal variety leads to seven degree of haematin. 3. Right gastric vein: It follows the lesser curvature and goes to the right to join the portal vein. It must be noted here that the right gastric vein receives prepyloric of Mayo. It is the landmark to identify the pyloric canal from the first part of the duodenum. 4. Cystic vein: It joins the right branch of the portal vein. 5. Paraumbilical veins: They accompany the ligamentum teres hepatic from the umbilicus to the left branch of the portal vein. In cirrhosis of liver veins are seen radially running away from the umbilicus. (Caput Medusae). 6. Superior pancreatico-duodenal vein: It opens into the portal vein. Following are the sites to be kept in mind 1. At the lower end of oesophagus. 2. At the umbilicus. 3. At the anal canal. 4. At the bare area of liver. 5. Between the veins of colon and left renal vein. 6. Through the veins which connect the intestinal veins with the inferior vena cava. 7. During embryonic life ductus venosus connects the left branch of the portal with the inferior vena cava. Normally this connection gets fibrosed to form ligamentum venosum. It begins at the hilum of the spleen by union of 4-5 veins. It is not tortuous like its accompanying artery. It runs in the lieno6-renal ligament behind the body of the pancreas towards the right to reach the neck of the pancreas. It lies below the splenic artery, which follows the upper border of the pancreas in a wavy course. At the neck of pancreas, splenic vein unites with the superior mesenteric vein to form the portal vein. Short gastric, pancreatic and left gastro-epiploic veins open into it. The most important, tributary of it, is the inferior mesenteric vein, which joins the splenic vein behind the body of the pancreas. It begins as a superior rectal vein. Superior rectal vein establishes connections with the middle and inferior rectal veins. It ascends upwards on the left psoas, where the inferior mesenteric artery lies to its right side. Next it passes either behind or infront of the duodeno-jejunal flexure and disappears behind the body of pancreas and joins the splenic vein. It receives veins from the left colic flexure, descending colon and the sigmoid colon. It brings blood from small intestine, the caecum, appendix, ascending colon and transverse colon. It runs from the right iliac fossa along the superior mesenteric artery which lies on the left. As it passes between the two layers of the mesentery. It crosses the inferior vena cava, third part of duodenum and the uncinate process of the pancreas to disappear behind the neck of the pancreas. It unites with the splenic vein behind the neck of pancreas to form the portal vein.

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Flow of Blood in the Portal Vein:

Development of Portal Vein:

Portal Hypertension:

Splenic Portography: Surgical Treatment of Portal Hypertension:

Portal vein has two slow streams of blood going towards the right and the left lobes of the liver. The right flow is formed by blood drained into the superior mesenteric vein, from the caecum, appendix, ascending colon and the right two thirds of the transverse colon. The reason for metastasis of the carcinoma of the ceacum into the right lobe of the liver is explained. Left flow of blood in the portal vein is formed by the blood drained into the splenic vein. Splenic vein receives blood from stomach, pancreas, spleen, descending colon, sigmoid colon, rectum and anal canal above the pectinate line. This explains the occurance of metastasis of cancer of sigmoid into the left lobe of liver. The infective emboli from the caecum and the sigmoid go to the right and the left lobes of the liver respectively. Two vitelline veins lie on either side of the developing duodenum. They are connected by three cross channels, two ventral, one cranial, and other dorsal. Both the ventral channels disappears and the right posterior and the left anterior channel also disappears. Splenic and the superior mesenteric veins join the left posterior channel near the dorsal channel. Left posterior channel, dorsal channel and the right anterior channel form the portal vein. Right branch of the portal vein develops from the right vitelline vein cranial to the ventral anastomosis and the remaining cranial part of the left cranial part of vitelline vein. Blood from the portal vein enters the hepatic veins and the inferior vena cava after passing through the liver. Block in the path of portal vein can be 1. Pre-hepatic - Congenital malformation or thrombosis or obliteration of the portal vein. 2. Hepatic - Cirrhosis of liver. 3. Post hepatic - Thrombosis of the hepatic veins, formation of the web. Involvement of the hepatic veins by the malignant cells. (Budd-Chiari syndrome). Methods of measures of portal pressure: 1. Direct by splenic puncture 2. By recording the pressure into hepatic veins by a cather passed through the basalic vein to the right atrium and the interior vena cava to the site of the tributaries of the hepatic veins. It is done under radiological control. It is special radiological investigation in which radio-opaque dye is injected into the spleen and the radiographic picture is obtained. Porta systemic shunt operation is done only when the sclerotherapy does not show desired results. Incidence of pre-hepatic obstruction is seen in 20% of the cases. On examination liver is not palpable and the ascitis is absent. However the spleen may be palpable. It is due to congenital abnormality of the portal vein, thrombosis due to normal process of obliteration of the left umbilical vein or due to the carcinoma of the pancreas. Hepatic 80% of obstruction is due to cirrhosis of liver.

Surface Marking:

Post-hepatic It is due to obstruction of hepatic veins as a result of constrictive pericarditis or obliteration of the veins by the malignant cells (Budd-Chiari syndrome). Mark a point on transpyloric plane 1.2 cm to the right of the mid-plane. Draw a broad line directed upwards and to the right having length of 8 cm.

Portal Vein

601

Surgical Treatments of the Porta Systemic Shunts Methods:

1. Porta caval – end to side or side to side. 2. Mesenterico-caval. 3. Lienorenal Severe jaundice, huge ascitis, low serum albumen, high serum bilirubin and abnormal anatomy of the vessels are the contra-indications for surgery. It is interesting to note and important to remember that the surgery is not done on those who have never bled.

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POSTERIOR ABDOMINAL WALL In the midline lies the vertebral column. A small portion of the 12th thoracic vertebra and all the five lumbar vertebrae form the anterior projection of the vertebral column. Vertebral bodies are covered with anterior longitudinal ligament. Lower down, the anterior longitudinal ligament, fuses with the periosteum at the sacral promontary. Psoas major muscle lies on either sides of the vertebral column. Immediately lateral to the psoas lies the quadratus lumborum muscle and lateral to quadratus lumborum is the transversus abdominis. Psoas major, descends obliquely downwards along the brim of the pelvis. Quadratus lumborum and transversus abdominis muscles are limited lower down by the iliac crest. Subcostal vessels ilio-hypogastric and the ilio-inguinal nerves are seen running from the lateral border of the quadratus lamborum muscle. Below the iliac crest lies the iliacus muscle which arises from the iliac fossa. Upper limits of the psoas and the quadratus are marked by the medial and the lateral arcuate ligaments (Figures 326). Figure 326 Showing muscles of posterior abdominal wall

The right and the left crura of the diaphragm are united by the ligament known as median arcuate ligament. Median arcuate ligament forms an arched anterior limit of the aortic opening. Right crus of the diaphragm arises from upper three lumbar vertebrae while the left crus arises from the upper two. Right crus of the diaphgram is stronger than the left as it has to contract against the heavy right lobe of the liver. It goes above and to the left to provide an opening for the oesophagus. It forms a “pinch cock” for the lower end of the oesophagus. Upper part of the posterior abdominal wall is formed by the diaphragm.

MUSCLES OF THE POSTERIOR ABDOMINAL WALL Psoas Major (Figure 328):

It arises from the lower border of the 12th thoracic vertebra, sides of the bodies of the five lumbar vertebrae, intervertebral discs, transverse processes and the tendinous arches which protect the lumbar arteries. It is inserted into the lesser trochanter of the femur along with the iliacus muscle. Psoas major is provided with a fascial sheath known as psoas sheath. It extends from origin to the insertion of the muscle. Psoas sheath provides a passage for the pus in case of tuberculosis of the lower thoracic and the upper lumbar vertebrae. It appears as a swelling at the upper part of the medial aspect of the thigh. (Psoas abscess)

Posterior Abdominal Wall Nerve Supply: Action :

Clinical: Psoas Test:

Psoas Abscess (Figure 327):

603

It comes from the 2nd, 3rd and 4th lumbar nerves. (Lumbar plexus itself is placed in the substance of the psoas major muscle). It is the flexor of the thigh upon the turnk and the flexor of the trunk upon the thigh. As regards its role in the rotation of the thigh there are three opinions. 1. It is the lateral rotator, 2. It is the medial rotator, 3. It has no role in rotation. In pertrochanteric fracture of the neck of femur psoas major muscle rotates the distal fragment laterally. When the inflamed appendix lies in contact with the right psoas major muscle, extension of the right hip gives pain. (Psoas test). When the inflamed appendix is in contact with the abturator internus muscle, flexion and the internal rotation of the thigh gives pain (Obturator test). Its incidence has fallen remarkably due to early dignosis and the treatment. Psoas abscess may halt in the iliac fossa above the inguinal ligament due to adhesions.

Figure 327 Showing psoas abscess

Figure 328 Showing psoas major and related nerves

Quadratus Lumborum (Figure 326):

It arises from the ilio-lumbar ligament, iliac crest and the tips of the transverse processes of the 3rd, 4th and 5th lumbar vertebrae. It is inserted into the front of the 12th rib. It lies between the anterior and the middle layers of the lumbar fascia. Nerve supply: From L 1, L2, L3. Actions: It fixes the last rib and allows the diaphragm to contracts.

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Iliacus Muscle: Retroperitoneal Space:

Retroperitoneal Tumours:

It arises from the iliac fossa and follows the psoas major muscle for insertion into the lesser trochanter in the femur. Blood or pus in the retroperitoneal space tends to go down towards the respective iliac fossae. If the retroperitoneal abscess develops it is better to evacuate by the shortest route through the abdominal wall. Retroperitoneal pus can follow the psoas major to the groin in the tuberculosis of the spine. Retroperitoneal haematoma is often caused by the fractured spine, leaking aneurysm and acute pancreatitis. Retroperitoneal cyst if large has to be differentiated from the hydronephrosis. Cysts of the retroperitoneal region arise from remnants of the Wolfian ducts. The cysts are removed through the trans-peritoneal incisions. Idiopathic retro-peritoneal fibrosis is the fibromatosis of the retroperitoneal tissue similar to the Dupuytrens contracture of the hand and the Peyronies disease of the penis. In Peyronies disease there is a formation of fibrous plaque in the tunica of the corpora cavernosa. It can be associated with mediastinal fibrosis. Fibrosis around the retro-peritoneal course of the ureters leads to renal failure. Majority of the patients come with the complaint of urinary retention and end with renal failure. Certain drugs such as beta-adrenergic antagonist can cause retroperitoneal fibrosis. 1. Retroperitoneal lipoma 2. Retroperitoneal sarcoma 3. Retroperitoneal cysts 4. Retroperitoneal growth from lymph-nodes 5. Adrenal tumours 6. Kidney – tumours of the kidney (Hypernephroma) and Wilms’ tumour 7. Nerve tissues—Neuroblastoma.

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KIDNEYS AND SUPRARENAL GLANDS

Capsules of the Kidney:

They are the bean-shaped paired organs lying on the posterior abdominal wall by the side of the vertebral column retroperitoneally. Right kidney lies at a lower level than the left due to the large size of the right lobe of the liver. Middle of the hilum of the right kidney lies at the transpyloric plane (L1). Upper poles are nearer the median plane than the lower. Anteroposterior plane of the organ is obliquely placed due to the median bulging produced by the vertebral column and the psoas major muscles. It must be remembered that the hilum does not face medially, but is directed anteromedially. Kidney presents the upper and the lower poles, concave medial and the convex lateral borders. It has an anterior and the posterior surfaces. (124 - indicates the approximate weight of the kidney 124 gm – 130 gm). Measurement of the kidney can be remembered as one two four, meaning thereby one inch (2.5 cm) is the thickness, two inches (5 cm) is the breadth and four inches (10 cm) is the length. They are three placed from inside out. 1. Inner fibrous capsule - part of its own, 2. Middle fatty capsule,

Aid to Memory: Fascial Capsule:

Fixation of Kidney:

3. Outer fascial capsule formed by the fascia transversalis. Remember ‘3 F.’, i.e. Fibrous, Fatty and Fascial. It is formed by the fascia transversalis (Fascia of Gerota). As the fascia transversalis meets the lateral border of the kidney it splits to enclose it. Anterior layer crosses the midline and continues with the similar layer on the opposite side across the midline. Posterior layer fuses with the fascia on the psoas major muscle and the lumbar vertebrae. Anterior layer of the fascial capsule of the kidney is known as fascia of the Toldt’s. While the posterior layer is known as fascia of Zukerkandl. In the vertical tracing renal fascia is continuous with the diaphragmatic fascia. Suprarenal gland is enclosed in the fascial capsule of the kidney, however it is separated by the transverse fascial septum. Therefore, when the kidney is brought to the surface during surgery suprarenal does not follow the kidney. The fascial capsule of the kidney is open below and as the result of the reduction of the perinephric fat kidney slips down. Kidneys are fixed on the posterior abdominal wall by the renal vessels, perinephric fat, paranephric fat, fascial capsule, peritoneum and the surrounding organs. Intra-abdominal pressure do help in fixation of the kidneys. When the peritoneal and the perinephric fat gets reduced, kidney slips down leading to the kinking of the renal pedical. (Nephroptosis) The ureter may get kinked leading to the symptoms of ureteric colic. Long term kinking of the ureter leads to hydronephrosis. (Hydronephrosis means an aseptic dilatation of the kidney due to obstruction to the outflow of urine partial or complete. It can be unilateral, bilateral, congenital, acquired, intrarenal or extrarenal). Surgical fixation of the kidney to the posterior abdominal wall is known nephropexy. (i.e. fixation of the kidney on the posterior abdominal wall is done in mobile kidney.)

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Relations (Figure 331): Posterior Relations:

Comment (Figures 329):

They are best studied as under: Right Kidney Left Kidney Diaphragm Diaphragm Quadratus lumborum Quadratus lumborum Psoas major Psoas major Transversus abdominis. Transversus abdominis. Subcostal vessels and nerve Subcostal vessels and nerve Ilio-hypogastric nerve Ilio-hypogastric nerve Ilio-inguinal nerve Ilio-inguinal nerve Relations of the posterior surface of both the kidneys are same. There is a difference of one intercostal space between the two, right being lower than the left. Upper pole of the right kidney lies at the 12th rib while that of the left at the 11th rib. Right kidney Anterior Suprarenal lies at the upper pole relations:

Left kidney Suprarenal lies along the medial border to occupy an area between the upper pole and the hilum

2nd part of duodenum over on the hilum.

Nil

Ascending colon.

Descending colon

Coils of intestine.

Coils of intestine

Upper surface is related to the liver (right lobe)

Nil Spleen is related to its lateral border Stomach (stomach bed) Splenic vein Splenic artery Pancreas Left colic flexor

Figure 329 Showing anterior relations of kidneys

Figure 330 Schematic diagram showing relations of left renal vein

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Figure 331 Showing posterior relations of right kidney (highly schematic)

Hilum: Structures in the Hilum: Macroscopic:

Microscopic:

Renal Circulation:

Further Details of Renal Circulation:

It is located at the middle of the concave medial border of the kidney leading to the sinus of the kidney. In the renal sinus, are the major and minor calyces of the pelvis of the ureter with blood vessels. Renal vein, renal artery and the pelvis of the ureter are placed antero posteriorly. Cut surface of the organ presents a fibrous capsule with cortex underneath in the outer zone and the medulla in the central. Medualla shows of 8-18 pyramids whose apices are directed towards the hilum and are known as papillae. They are milked by the smooth muscle sphincters of minor calyces. Each of the pyramid is crowned by the cortical tissue. This constitutes the lobe of the kidney. Study is made under two heads 1. Microscopic anatomy of the secreting portion. 2. Microscopic anatomy of the collecting portion. Secreting part is represented by small and numerous glomeruli. Glomeruls is the tuft of vessels lying in the glomerular capsule (Bowman’s capsule). Each tuft has an afferent and an the efferent vessel. They are seen in plenty in a section passing through the cortex. Collecting portion presents the glomerulas, convoluted tubule, descending limb, loop of Henle and the ascending limb. 1. Renal arteries are direct branches of abdominal aorta, hence are the high pressure arteries. 2. Branches of the renal arteries inside the kidney arise at right angle hence they too maintain high blood pressure. 3. Glomerular plexus has pre-glomerular arteriole and the post glomerular arteriole that too of a smaller diameter, which creates higher pressure in the glomerular plexus. 4. Efferent arterioles of the glomerular capillary have an unique distinction, as they begin as capillaries and end as capillaries. (Renalportal circulation). 5. Corticle circulation is large and it does the job of filteration while the medullary circulation is small and does the job of urinary concentration. 6. Renal artery stenosis causes ischemia of the kidney which releases renin. 1. Renal artery divides into the anterior and the posterior branches. Anterior branch passes infront of the pelvis of the kidney, while the posterior branch passes behind. Anterior branch divides into

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Juxtamedullary Apparatus:

Development (Figure 332):

Figure 332 Showing development of kidney

four branches and the posterior continues as the fifth branch. 2. Segmental arteries divide into lober branches, which divides into inter-lober arteries. Each inter-lober artery runs along the side of the pyramid and divides at the cortico-medullary junction to form the arcuate artery. Arcuate arteries from the arch cap for the base of the pyramid. They do not anastomose with each other and hence are end arteries. 3. Interlober arteries arise from the arcuate arteries at right angle to the arcuate artery and run towards the capsule of the kidney through the cortex. 4. Afferent glomerular arteriole is given by the interlobular arteries. Efferent glomeruli arteries leaves the glomerular plexus and form the second capillary plexus and the ascending and descending roots of renal tubule. Here as the blood passes through the two sets of capillaries it is known as renal portal circulation. 5. Efferent glomerular arterioles break in number of branches and enter the outer part of the medulla at straight artery. They are known as vasa-recti. They form an intricate plexus in the anal part of the medulla which is in close contact with the loop of Henle and the duct. Ascending vasa recti leave the venous end of the plexus and join the arcuate vein or inter-lobular veins. Blood supply of the medulla is mainly controlled by juxta medullary glomeruli. It contains of macula densa, juxta glomerular cells and the mesangeal cells. Maculi densa consists of the cells of the proximal convoluted tubules. Due to the change in pressure can stimulate the juxta glomerular cells to produce renin. Juxta glomerular cells are the modified cells of the afferant arteriole. They contain granules. Mesangeal cells are the cells which suspend the glomeruli. Kidneys are mesodermal in origin. They develop from the urinary part of the urogenital ridge on the posterior abdominal wall in the pelvic region. Development is in three stages. 1. Pronephros. 2. Mesonephros. 3. Metanephros: It gives rise to secreting portion of the adult kidney. Collecting portion develops from the the mesonephric duct (Wollfian duct) which gives the ureteric bud. As the uretric bud grows cranially it is capped by the metanephric cap. Metanephric cap forms the secreting portion of the adult kidney, while the collecting part is formed by the ureteric bud. Failure of union of the secreting and the collecting parts of the kidney, leads to formation of polycystic kidney. Kidneys are in the pelvic region and ascend between the 5th and 8th week of intrauterine life to reach the lumbar region. They also undergo rotation, so that the hilum points medially instead of anteriorly. Large right lobe of the liver prevents the right kidney from ascending to the level of left kidney.

Kidneys and Suprarenal Glands Congenital Anomalies of the Kidney:

Clinical :

609

1. Absence of kidney. 2. Congenital polycystic kideny: It is due to nonunion of collecting and secreting portions of the kideny. Intravenous pyelographic appearance is typical as the pelvis elongates and the calysis get stretched over the cysts like spider legs. 3. Pelvic kidney 4. Horse shoe kidney: Lower poles are fused to form a bridge. Horse shoe kideny is prone for the infection, stone and the tuberculosis. 5. Foetal or lobulated kidney 6. Ectopic kideny 7. Crossed ectopia. 1. Vascular segments of kidney (Figure 333): Each kidney has five vascular segments based on the distribution of five segmental branches. They are as under a. Apical b. Basal c. Post d. Upper Anterior e. Lower Anterior

Figure 333 Showing vascular segments of right kidney viewed from lateral side

Renal Angle :

Apical and the basal segments are limited to the poles and include both the anterior and the posterior surfaces. Rest of the kidney is divided into anterior and posterior parts. Anterior part is further divided into upper anterior and lower anterior. The undivided posterior part of the kidney forms the posterior segment. Segmental resection of the kidney is possible if the disease is limited to the segment. 2. Renal transplant: Iliac fossa on the posterior abdominal wall is ideally selected for positioning the kidney anterior to the iliacus muscle. Renal artery is anastomosed to the internal iliac artery and the renal vein is anastomosed with the external iliac vein. 3. Aberrant renal arteries: One to two aberrant renal arteries are seen in females that too on the left side. Normally it is not the cause of the hydronephrosis. These arteries being functional end arteries, their ligation can lead to disaster causing necrosis of the part of the kidney supplied. It is an angle between the twelfth rib and the lateral border of the erector spinae muscle. Point is of clinical interest are : 1. Kidney is close to the surface and can get easily injured. 2. It is the site where the patient complains of pain and the tenderness is elicited by the clinician. 3. Perinephric abscess makes its first appearance at the renal angle. 4. Lower border of the pleural reflexion passes through the renal angle. Hence the upper end of the incision for the exposure of the kidney should begin lower down.

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Clinical:

Renal Stones:

Artificial Kidney:

Injury to the Kidney:

Renal Pain:

1. Infection of the Kidney is known as nephritis. It is of two types (i) acute and (ii) chronic. In acute nephritis early morning oedema appear on the face. Albumin is present in the urine along with pus cells and R.B.C.s. Chronic infection of the kidney leads to anemia and hypertension. Kidney gets small and contracted which can be confirmed by Ultra-sound examination. 2. Perinephric abscess: It is due to infection of perinephric haematoma. Tuberculosis of the adjoining vertebra can also cause perinephric abscess. Abscess from the renal cortex may burst inside the renal capsule. Rarely an appendix abscess may extend to the perinephric space through the renal capsule. Loin shows fullness and there is abdominal tenderness, however urine does not show pus cells. The swelling and the tenderness is less marked if the abscess is at the upper pole, as the upper pole is well shielded by the lower ribs. Plain X-ray of the abdomen shows obliteration of the psoas shadow, arching of the spine towards the abscess and the raising of the diaphragm. Ultra Songography or C.T.Scan is diagnostic. It should be incised and drained through a liberal incision and not aspirated. Perinephric abscess does not spread to other side due to the fusion of the fascia transversalis to the front of the great blood vessels or its closure at the renal pedicle. They are formed in the pelvis of the kidney and may occupy one of the calyx. It gives pain at the renal angle. The stone may enter the ureter giving ureteric colic. At times small stones from the kidney are passed through the urethra. There are three common sites of normal constrictions of the ureter (1) At the pelvi-uretric junction, (2) At the brim of the pelvis and (3) At the uretero-vasical junction. Obstruction leads to stasis, and stasis leads to infection. Long term obstruction of the ureter lower down leads to hydro-ureter and the hydronephrosis of the kidney. It is difficult to spot the small size uretric stones. They are situated along the course of the ureter which corresponds to the tips of the lumbar transverse processes, sacroiliac joint and the ischial spine. The radio-luscent stones can be seen by doing intra-venous pylography. Small stones give more trouble than large stones. Ureteric colic is mostly due to small stones. A large stone occupying the pelvic of the ureter and the renal calysis is known as staghorn calculus. Percutaneous removal of the stone with the nephroscope can be done. Extra corporeal shock wave lithotripsy (ESWL) is done by an instrument known as lithotripter. It generates shock waves which breaks the stone. In bilateral renal failure the patient is put on haemodylisis. (Artificial kidney). Initially a subcutaneous arterior venous fistula of Cimino is created between the redial artery and the cephalic vein at the wrist. It is injured by the stab and the gunshot more than the blunt trauma. Injury to the kidney may result in contusion, laceration or avulsion of the kidney pedicle. The blood loss in the renal trauma is enormous as 25% of the cardiac output goes to the kidney. In avulsion of the kidney pedicle kidney is removed (nephrectomy). It is due to the contraction of the smooth muscle fibers of the pelvis of ureter. Due to obstruction by the renal stone, the pain is felt in the flank and the anterior abdominal wall along the subcostal nerve.

Kidneys and Suprarenal Glands Mobile Kidney:

Hypernephroma:

Tumours in Children (Wilms’ Tumour): Nephroblastoma: Approach of Removal of Kidney (Nephrectomy) :

611

Position of the kidney on the posterior abdominal wall is maintained by the renal pedical, perinephric fat, surrounding organs and the intraabdominal pressure. In case of loss of perinephric fat kidney slips down which leads to kinking of the pedical. It is a malignant tumour of the kidney which on spread to the lungs gives typical cannon balls appearance in the x-ray of chest. Malignant cells of the hyper-nephroma block the left renal vein. As a result patient develops left sided vericocele due to blockage of the left testicular vein. On palpation of the scrotum varicocele feels like a bag of worms. It arises from embryonic nephrogenic tissue. It spreads rapidly to the lungs via blood stream. The secondaries in the bone goes in favour of nephroblastoma. Intravenous pylography, U.S., C.T.Scan are the investigations needed. It is done by approaching the kidney through the lumbar incision. This approach is extraperitoneal. However, care should be taken to protect the lower margin of the pleura. Subscapsular nephrectomy: It is done when there are addisions in the perinephric tissue. Laproscopic nephrectomy: Laproscopic nephrectomy can be done in small kidney.

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SUPRARENAL GLANDS They are the paired endocrine organs located retroperitoneally on the posterior abdominal wall, at the upper pole of the kidneys. Each of them presents cortex and the medulla. Although the organ is smaller, It has rich blood supply. It is separated from the kidney by means of the fascial septum of the fascia transversalis. Kidney slips down with the disappearance of the perinephric fat but the suprarenal does not follow the kidney due to the fascial septum (Figure 334). Figure 334 Showing anterior relations of supra-renals

Description, relations, blood supply and the venous drainage is given in the form of comparative chart. This helps in memorizing the relations of the right and the left suprarenals. Heading

Right

Situation

At the upper pole of Situation along the right kidney medial border between the upper pole and the hilum of the left kidney

Shape

Triangular

Semilunar

Weight

4 gm

4 gm

Anterior relations:

Note (Figures 335 and 336):

Investigations: Clinical:

Left

Liver and inferior vana cava Stomach the splenic artery and the Pancreas.

Posterior relations:

Diaphragm and kidney

Diaphragm and kidney

Blood Supply:

From phrenic

From phrenic

From renal From aorta

From renal From aorta

Venous drainage:

Go to the inferior vena cava

Go to the left renal vein

Blood supply of the supra-renal is profuse. Right supra-renal vein is shorter and directly joins the inferior vena cava. This makes the removal of the right supra-renal a formidable job for a new surgeon. On the other hand the removal of the left supra-renal is easier. Left supra-renal vein joins the left renal vein which has connection with azygos vein, the left inter-costal, internal mammary and vertebral veins. This is the reason of the different sites of metastasis of malignant tumours of the supra-renal on the right and the left. An adrenal mass can be diagnosed by C.T. Scan. In 90% of the cases the ultrasonography can detect tumours larger than 2 cm. 1. Addison’s disease (hypocorticism) : In this condition there is a progressive destruction of the cortex and the medulla. The condition may be associated with tuberculosis of the gland. In this syndrome there is low blood pressure, muscular weakness, pigmentation of skin at the points of pressure. Pigmentation of the oral mucosa is peculiar.

Suprarenal Glands

613

Figure 335 Showing blood supply of supra-renal glands

Figure 336 Showing venous drainage of supra-renals and testes

Pheochromocytoma:

Clinical:

Surgical Removal of Supra-renal:

2. Cushing syndrome: It is common in female and is due to the hyperplasia, adenoma or the cancer of the cortical tissue. Large abdomen, thick neck and slender legs due to muscular atrophy is the picture of a classical case of cushing syndrome. It looks like a lemon on matchsticks. There is a collection of fat on the seventh cervical spine which is known as buffalow hump. There is obliteration of supraclavicular fossa. Amenorrhoea in female and impotance in male are common. Hypertension is the constant finding. Face is round and is classically described as the moon face. Note: Cortex of the supra-renal produces 1. Mineral corticoid 2. Gluecocorticoid 3. and Sex hormones The medulla of the supra-renal produces adrenaline and non adrenaline. It is the tumour arising from the chromaffin cells of the adrenal medulla. 90% of the pheochromocytomas are in the medulla. However extra-renal site is also known such as organ of Zuckerkandl which lies at the bifurcation of the aorta. There is paroxysmal or persistant hypertension with headache, and patient has the fear. Patients suffer from palpitation of heart, sweating and dyspnoea. Failure to diagnose pheochromocytoma is a failure to think of the disease. A postero-lateral wide incision is given like that for the kidney. 12th rib is removed sub-periosteally and the lower border of the pleura is pushed up. Finally the incision is given in the bed of the 12th rib. Presentation of

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Development:

Histology: Cortex:

Medulla:

fat indicates that the surgeon has reach the gland. Removal of the suprarenal gland is hazardous on right side due to the short and thin right supra-renal vein which directly goes to the inferior vena cava. It is likey to get torned. The operative management is difficult as you touch the gland, blood pressure shoots very high may be upto 600 mm of Hg. When the tumour is removed the blood pressure comes down remarkebly. Cortex of the suprarenal develops from the coelomic epithelium which is mesodermal and the medulla develops from the neural crest, which is ectodermal in origin. It presents a thin capsule. Under the capsule lie cortex and the medulla. Presents - polyhedral cells arranged in different layers: 1. Zona glomerulosa, 2. Zona fasciculata, and 3. Zona Reticularis. Presents - sinusoids, chromaffin cells and the few nerve cells. Chromaffin cells secrete adrenaline and noradrenaline.

Ureter

615

URETER

Pelvis of Ureter: Constrictions of the Ureter:

It is a thick muscular tube which carries urine from the kidney, to the urinary bladder. It begins at the pelvi-ureteric junction, runs downwards crosses the brim of the pelvis and the bifurcation of common iliac artery or the external iliac artery. Ureter is retro-peritoneal. It enters the pelvic cavity and joins the urinary bladder at the uretero-vasical junction. It is 25 cm in length. Anatomically ureter is divided into three parts, abdominal, pelvic and intramural. It is the proximal dilated part of the ureter known as the pelvis of the ureter. It is formed by the union of 2 to 3 major calyces. They are three in number: 1. At the pelvi-ureteric junction, 2. At the brim of pelvis, 3. At the entry into the urinary bladder. The sites of constriction of ureter are clinically important as ureteric stone can get lodged at the constrictions. Surgeon has to negotiate the constrictions during passage of the ureteric catheter or the stent (Figures 337, 338 and 342) Relations : The abdominal part of ureter : Anterior:

Right

Left

Peritoneum

Peritoneum

2nd part of duodenum Right colic vessel

Left colic vessels

Right ileo-colic vessel Right testicular or ovarian vessels

Left testicular or ovarian vessels

Root of mesentery

Mesocolon of sigmoid

Terminal part of ileum

Sigmoid colon

Sigmoid recess Posterior:

Pelvic part of the Ureter: General Course (Figure 340): Relations of Pelvic Part of Ureter in Female (Figure 341):

Psoas Major

Psoas Major

Genito-femoral nerve

Genito-femoral nerve

Tips of transverse processes of the lumbar vertebrae, sacroiliac joint and the ischial spine

Tips of transverse processes of the lumbar vertebrae, sacro-iliac joint and the ischial spine

On the right of the Inferior vena cava lies the right ureter and on the left of the Inferior mesenteric vein lies the left ureter (Figure 339). It runs downwards along the lateral pelvic wall in front of the internal iliac artery and its anterior division. At the level of the spine of the ischium, it turns medially and forwards to open into the urinary bladder at its lateral angle. Pelvic part of ureter in female after reaching the ischial spine it turns medially forwards and goes under the broad ligament of the uterus where it is crossed by the uterine artery from above. Ureter passes infront of the vagina and opens in the urinary bladder at superior lateral angle. Ureter in female lies 2.5 cm lateral to the supra vaginal part of the cervix. Left ureter in female has more intimate relation with the lower part of the cervix and the left lateral vaginal fornix, as the fundus of the uterus has tendency to shift to the right.

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Figure 337 showing ureters, inferior vena cava and portal vein (top). Posterior relation of right ureter (bottom)

Figure 338 Showing anterior relations of right ureter

Figure 339 Showing relations of testicular or ovarian arteries to the ureters

Ureter

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Figure 340 Pelvic courses of ureter and vas in male

Figure 341 Showing pelvic part of right ureter in male

Relations of Pelvic Part of Ureter in Male:

Blood Supply :

Nerve Supply:

Histology:

After crossing the brim of the pelvis and the bifurcation of the common iliac artery, ureter runs on the lateral pelvic wall to reach the pelvic floor at the ischial spine. During this course from brim to spine it is related to obturator internus muscle, obturator fascia, obliterated umbilical artery, obturator nerve, obturator artery, obturator vein, inferior vesical and the middle rectal arteries, under the peritoneum. The ureter crosses all the structures superficially from the medial side. Ureter is crossed by the vasdifference at the supero-lateral angle of the bladder from the front. Upper end of the seminal vesical is related to the end of the ureter. Note: Intra-mural oblique course of the ureter acts as a valve preventing reentry of urine from the bladder to the ureter (reflux). It is supplied by branches from testicular, renal, aortic, internal iliac and the inferior vesical arteries in the male and gets supply from the ovarian vaginal and the uterine arteries in the female in addition to the branches from the aorta and the renals. Note : There is no inferior vesical artery in female instead they are replaced by vaginal and uterine. Peritoneum itself is an important source of blood supply for the ureter. Stripping of the peritoneum from the ureter can cause ischemia, necrosis of the ureter. It comes from 10th, 11th, 12th thoracic and 1st lumbar and 2nd , 3rd 4th sacral segments. Ureteric pain begins in the loin and descends downwards towards the testis along the 10th, 11th, 12th thoracic and 1st lumbar segmental areas of skin. It is the thick muscular tube having a star-shaped cavity lined by transitional epithelium. It presents a fibrous, muscular and the mucous coats. Muscular coat is made of smooth muscles. Normally in the upper part, inner coat is longitudinal while the outer is circular. In the lower part, extra longitudinal outer coat is added. With the appearance of this coat, inner longitudinal coat in the lower part gradually disappears.

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Clinical:

Development: Anomalies of Ureter:

Extreme degree of narrowing of the ureter at any of the three sites of constrictions can lead to hydro-nephrosis. (Hydronephrosis means aseptic dilatation of the kidney). 1. Obstruction leads to stasis; stasis leads to infection and the infection leads to stone formation. 2. Injury to the ureters are not common due to its deep well protected location. However gun-shot and stab can damage the ureters. Damage to the ureter is well known during the operation of hysterectomy (removal of uterus). If detected at the time of operation it should be repaired immediately. If not detected at the time of operation IVP (Intra venous pyelograph) should be done which certainly spots the site of injury. If the loss of the part of the ureter is small it should be anastomosed. If the loss of the segment of the ureter is long the ureter can be anastomosed to the ureter of the normal side. (Uretero-ureteric anastomosis). If the loss of ureter is long near the urinary bladder the flap from the urinary bladder can be utilised for constructing the ureter. (Bowari’s operation). Ureter is mesodermal in origin and develops from the ureteric bud arising from the distal part of mesonephric duct (Figuer 342). 1. Double ureter, 2. Retrocaval ureter, 3. Ectopic opening of ureter—opening in the vagina.

Figure 342 Showing anterior relations of left ureter

In female the ectopic opening is below the sphincter, hence there is incontinence, however in male the ectopic opening is above the sphinter hence no incontinence. 1. During operation the ureter can be identified by its thickness and peristaltic movements. 2. The course of the ureter is across the tips of the lumbar vertebrae, sacro-iliac joint and the spine of ischium. Radio-opaque stone should be searched along the ureteric line. 3. Peritoneum is adherent to the ureter. During surgery as the peritoneum is lifted the ureter is seen plastered to its under surface. 4. Ureteric colic radiates to the scrotum. 5. Double ureter: Duplication of the ureter is usually seen in the lower part and both open in the bladder by a common opening. Sometimes they open independently. The ureter from the upper part of the pelvis opens distally.

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6. Retrocaval ureter: Right ureter instead of being on the right of the inferior vana cava lies posterior to it. Treatment of the retrocavel ureter is the division of the ureter and anastomosis in front of the inferior vena cava. 7. Congenital megaureter: There is enormous dilatation of the ureter due to the functional obstruction at the lower ureteric end. 8. Ureterocele: It is the dilatation of the intra-mural part of the ureter due to atresia of the lower ureteric orifice.

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SMALL INTESTINE

Root of Mesentery: (Figure 343)

It is the coiled muscular tube having three parts (1) C – shaped duodenum, (2) jejunum and (3) the ilium. Duodenum is retro-peritoneal, widest and most fixed part of the small intestine without mesentery, except for its 1.25 cm proximal part. It is due to the extensions of the greater and lesser omentas. It makes the proximal part of the first part of the duodenum mobile and it lies infront of the head of the pancreas. In the barium meal examination this part forms a duodenal cap, rest of the small intestine such as the jejunum and ileum are hanging from the posterior abdominal wall by means of the mesentery. Although the free margin of the mesentery is of a considerably length. (20 feet). Its root is hardly 15 cm in length while its breadth is only 20 cm. Attachment of the root of the mesentery to the posterior abdominal wall is obliquely set, running from the doudeno-jejunal flexure on the left to the ileo-caecal junction on the right. During its course it crosses the following structures from above downwards:

Figure 343 Showing relations of root of mesentry

1. 2. 3. 4. 5. 6. 7. 8.

Fourth and the third parts of duodenum. Abdominal aorta. Inferior vena cava. Right psoas major. Right psoas minor (when present). Right genito-femoral nerve. Right Ureter. Right Testicular or ovarian vessels.

Contents of the mesentery: 1. The intestine: Jejunum and ileum. 2. Fat. 3. Mesenteric lymph nodes. 4. Lymph vessels. 5. Superior mesenteric vessels and their sympathetic nerves. 6. Lacteals.

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Small intestine is divided into three parts, viz., duodenum, jejunum and the ileum. As a rule proximal two-fifths is named as the jejunum and the remaining three-fifth as the ileum. Following are the differences between the jejunum and ileum. Jejunum (2/5)

Ileum (3/5)

1. Circular folds are larger and 1. Circular folds are smaller and less in more in number and can be palpated number and disapper distally

Payer’s Patches:

Structure:

Blood Supply of Small Intestine (Figure 344):

2. It is wider but empty (4 cm)

2. Narrow but loaded (3.5 cm)

3. Villi are larger and thick

3. Short and thin

4. Aggregated lymphatic follicles are present only in the lower part and are circularly arranged

4. Aggregated lymphatic follicles are arranged along the long axis of the ileum Peyer’s patches

5. Thick walled

5. Thin walled

6. From out side walls look red due to more vascularity

6. Does not look so red due to less vascularity

They are aggregated lymph follicles (Nodules) present in the lower part of the ileum. Situation — Along the antimesenteric border in the long axis of the ileum. Shape — Oval Size — 5-10 cm long Number — About 25-30 in numbers. They are made-up of lymphocyte and plasma cells. Age changes : In children it is well developed and infancy. (like transit and disappears in old age. Superior mesenteric artery is the artery of the midgut. It takes origin from the abdominal aorta at the first lumbar level and runs downwards crossing the uncinate process of the pancreas and the third part of the duodenum from the front. Its further course is in the root of the mesentery. As it runs downwards and to the right, presents a concavity towards the right. The artery ends at the right iliac fossa.

Figure 344 Showing vascular pattern of ileal mesentery

Vascular Pattern of Mesentery:

Branches of the superior mesentery artery: (Figure 345) 1. Mid-colic, 2. Right colic, 3. The ilieo-colic. They are given from the right concave side of the artery. From its convex (left) side number of vessels are given to the small intestine. These vessels on their way to the intestine form series of arterial arcade in the mesentery which are better seen against light. 15-20 jejunal and ilial branches are given from the convex side of the superior mesenteric artery. They form arterial arcades which are less in

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Figure 345 Showing branches of superior mesenteric artery with vascular pattern of jejunal mesentery

Venous Drainage:

Clinical:

Anomalous Conditions:

the jejunal part of the mesentery, hence, vasa-recti are long. The arterial arcades in the ileal mesentery are more hence, the vasa recti are short. Due to the absence of fat the arterial windows in the jejunal mesentery are clearly seen against light. On the other hand due to the presence of the fat in the ileal mesentery the arterial windows are seen as if viewed through the ground glass. Terminal part of the ileum is supplied by the ileo-colic branch of the superior mesenteric artery. Venous drainage goes to the portal vein through the superior mesenteric vein. The vein runs in the mesentery lying on the right side of the superior mesenteric artery. Higher up it passes in front of the 3rd part of duodenum and the uncinate process of the pancreas and disappears behind the neck of pancreas and joins the splenic and forms the portal vein. 1. Length and free mobility of the small intestine give freedom to it to enter the hernial openings. 2. In enteric fever (typhoid), Payer’s patches enlarge and ulcerate. They are placed along the long axis of the intestine. Therefore they do not obstruct the lumen after fibrosis. On the other hand tubercular ulcers are placed horizontally around the wall of the lumen form strictures leading to intestinal obstruction. 3. Enteric perforation: Cases of enteric perforations are not seen these days. Thanks to its falling incidence. Every case of the enteric perforation had a gloomy postoperative future and the surgeon invariably used to opt for nonoperative management. 4. Round worms : The incidence of round worm infestation is common in rural areas. Obstruction of the small bowel by the bunch of round worms is not uncommon. 5. Meckle’s diverticulum: It is the remnant of the vitelo-intestinal duct situated at the anti-mesenteric border of the ileum. Its incidence is 2%. It has a length of 2 inches (5 cm). It is two feet away from the ileo-caecal junction and may have two types of ectopic tissues, the gastric and the pancreatic. Meckle’s diverticulum is attached to the anterior abdominal wall at the umbilicus by means of a fibrous band. Coils of intestine can rotate around the fibrous band leading to the intestinal obstruction. Complications caused by Meckle’s diverticulum (Figure 347) 1. Peptic ulcer 2. Intussuception 3. Intestinal obstruction 4. Attack simulating the attack of acutre appendicitis. 1. Patent Meckle’s diverticulum. It opens at both the ends forming the faecal fistula.

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2. Presence of fibrous band from ileum to the umbilicus. It may promote intestinal obstruction. 3. When the umbilical end is patent and the ileal end fibrous it forms an umbilical sinus. 4. When both the ends, e.g. umbilical and the ileal becomes fibrose and the middle part forms the cyst. 5. Free type in which the stump looks at the umbilicus when it is from the ileus and the stump looks at the ileus when it is from the umbilicus.

Silent Meckle’s Diverticulum: Litter’s Hernia: Internal Herniation:

Intussuseption:

Volvulus of Small Intestine:

Superior Mesenteric Artery Embolism:

Seat-belt Syndrome:

Mesenteric Tear (Figure 346):

Large Intestine: Caecum (Figure 348):

Note: After every appedi-sectomy for acutre appendicitis, the terminal part of the ileum should be thoroughly checked for the Meckle’s diverticulum as a routine. In case the appendix is found normal, it is still more pertinent and obligatory to search for the Meckle’s diverticulum. When searched, it is not found and remains dormant and symptomless during life. It is found only after death during the post-mortem examination. When the Meckle’s diverticulum is found in the hernial sacs of inguinal or femoral hearnia, the hernia is known as Litter’s hearnia. Loops of the small intestine may enter one of the peritoneal recesses and produce intestinal obstructions. The fold of the para-duodenal recess carries the inferior mesenteric vein. (Vascular fold). The superior ilio-ceacal recess is bound by bloodless folds of Treves. It is the telescoping of the proximal part of the gut into the lumen of the distal part. Iliocaecal type is common due to the disproportionate size of the organs. There is palpable abdominal lump and the right iliac fossa is empty. Filling of the emptiness in the right iliac fossa due to displaced ceacum. Empty right iliac fossa is recognized as “sign of dance”. It is commonly seen in the ileum and is caused by adhesions passing from the ante-mesenteric border of the intestinal loop to the parietal peritoneum or the pelvic organs in female. Large vegetable meal such as rice, maze and vegetables are the precipitating causes. Untwisting of the loop and cutting of the bands obstructing the loop is required. Superior mesenteric artery is commonly involved in embolism. The embolus coming from the heart in case of the recent myocardial infarction resulting gangrene of the parts of the gastro-intestinal part supplied by the superior mesenteric artery. It needs surgical excision of the gangerenous gastrointestinal tract. Phenomenon of embolism is uncommon in the inferior mesenteric artery due to better collateral circulation. Sudden deceleration of a car in an accident while the seat-belt is on, leads to mesenteric laceration and tear of the mesentry. There is profuse internal hemorrhage and the 60% of the cases have intestinal lacerations and the patient requires immediately laparotomy. In the vertical mesenteric tear blood supply of the intestine is not very much affected and mere suturing of the mesentery is enough. In the horizontal tear there is deprivation of blood supply to the large segment of the small intestine. Such cases need resection and anastomosis. Its length is hardly 5 to 6 feet. It presents for examination an appendix, caecum, ascending colon, transverse colon, descending colon, pelvic colon and the rectum. The meaning of the word caecum is blind. It is the pouch at the beginning of the ascending colon. Ascending colon and the caecum are situated above the right half of the inguinal ligament. Medially it communicates

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Figure 346 Showing horizontal tear in mesentery which requires resection of the part of the gut. Vertical tear needs suturing of the torn mesentery only

Figure 347 Showing development of Meckel’s diverticulum and anomalies

Figure 348 Showing caecum and appendix

with the terminal ileum and above with the ascending colon. Caecum is one of the organs whose breadth is more than the length being 6 cm and the breadth being 7.5 cm. A small finger like process is seen attached to its postero- medial aspect of the caecum 2 cm below the ileocaecal junction is the appendix. Caecum occupies the right iliac fossa. Anterior taenia coli is seen leading to the base of the appendix. It is followed by the surgeon during appendisectomy which takes him to the base of the appendix.

Small Intestine Relations of Anterior Surface of the Caecum: Relations of Posterior Surface (Figure 349):

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1. Anterior abdominal wall 2. Greater omentum 3. Coils of the intestine. Caecum lies in the right iliac fossa on two muscles, three nerves and three arteries which can be described as ceacal bed (Bed of the ceacum). Structures under the caecum belongs to the right side of the body. 1. Iliacus, 2. Psoas major muscles, 3. External iliac artery, 4. Lateral cutaneous nerve of thigh, 5. Femoral nerve, 6. Genitofemoral nerve 7. Testicular or ovarian vessels. 8. Iliac branch of ilio-lumbar artery.

Figure 349 Showing structures in the caecal bed (i) muscles, (ii) arteries, and (iii) nerves

Shapes of the Caecum:

IIeo-colic Opening:

Functions of the Ilio-caecal Valve: Mechanism of Closure of Ileocaecal Valve (Figures 352 and 353):

Note : Behind the ceacum lies the retro-caecal space which is occupied by the appendix in 75% of the cases. Caecum has different shapes which are due to its embryological peculiarities. The caecum is covered with the peritoneum on all the sides which grants mobility to the organ. Commonest position of appendix is retrocaecal. 1. Infantile type (conical): Appendix arises from the lower end of the caecum. 2. Quadrate type, 3. Intermediate type: appendix is placed between the two equal pouches of the caecum. 4. Extreme degree adult type (Ampullary) : where the caecal out- pouching is larger. It is seen 75% of the cases. It is guarded by a special valve known as the ileo-colic valve. It has two lips: (1) Upper, and (2) The lower. Both the lips are connected at their ends to form the frenulum which runs horizontally. Lips of the valve are formed the invagination of the terminal portion of the ileum into the colon. Cavity of the appendix communicates with the cavity of the caecum through a small opening lying 2 cm below the ileo-colic orifice. Controls entry of the ileal contents into the caecum and prevents regurgitation of caecal contents into the ileum. Sympathetic stimulation closes the ileo-caecal valve, however the important factor is mechanical due to the distension of the caecum. The valves gets closed as the lips are pulled apart horizontally by the frenulum.

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CLINICAL Acute on Chronic Obstruction:

Blood Supply of the Caecum

Venous Drainage: Nerve Supply: Morphology of the Caecum: Development of the Caecum (Figure 351): Clinical :

Mal-rotation of the Colon : Iliocaecal Tuberculosis:

Carcinoma of the Caecum: Appendicular Abscess: Caecostomy : Volvulus of Caecum:

Appendix (Figure 350):

When the large intestine is obstructed it is the caecum which bears the burden and goes on dialating. As a result ileo-caecal valve becomes incompetent. The faeculant caecal contents enter the ileum and are brought out by vomitting. Patulous ileocacal valve can produce the similar symptoms. Caecum is supplied by anterior and the posterior caecal branches of the ilio-colic artery which itself is the branch of the superior mesenteric artery. Many times posterior caecal artery receives a recurrent branch from the appendicular artery. It forms an anastomotic vascular circle around the base of the appendix. Surgeon has to remember this fact during crushing of the appendicular stump. It goes to the superior mesenteric vein. Sympathetic nerve supply comes from T11 to L1. Parasympathetic supply is from vagus. It is the upright position of the human being which has brought the caecum to the right iliac fossa. Caecal bud arises from the post-arterial segment of the midgut in the form of a diverticulum. Appendix arises from the apex of the caecum. Due to rapid growth of the right caecal wall the appendix is shifed to the left. 1. Inflammation of the caecum is known as typhlitis 2. Caecum is involved in amaebiasis which may lead to amoebic liver abscess. 3. Ileocaecal intussusception presents with a lump in the abdomen and the empty right iliac fossa (Sign of dance). The caecum fails to come down to the right iliac fossa and remain in the sub-hepatic position. Acute attack of appendicitis in such cases is the great diagnostic challange. It is usually of hyperplastic type and presents as a lump in the right iliac fossa. Appendicular lump, carcinoma of caecum, Chron’s disease, tuberculosis, actinomycosis, iliac lymph-adenopathy and the right ovarian tumour are the likely causes of lump in the right iliac fossa. Differential diagnosis of the lump in the right iliac fossa is a common question in surgery. It presents as resistant type of anaemia with the lump in the right iliac fossa. It is important to remember that a case of carcinoma of the caecum may present with signs and symptoms of acute appendicitis. Acute appendicitis follows the obstruction of the appendicular lumen by the carcinoma. Appendicular abscess which resists treatment and refuses to resolve could be the case of “CARCINOMA OF THE CAECUM” An artificial opening is made in the caecum in case of the obstruction particularly in the patients who are severely ill. It is a shortcut measure which gives time to the patients to improve. Loose, lax and mobile right half of the colon favours the volvulus of the caecum which is clockwise. It is common in female and presents with acute abdominal pain, nausea and the vomiting (90%). First turn obstructs the ascending colon and the second one obstructs the ileum. Barium enema confirms the diagnosis. If gangerenous right hemicolectomy is done. Appendix is a muscular tube with one end blind. It is a finger like a process projecting from the posterior medial aspect of the caecum. It has a body, base and an apex along with a small meso-appendix. It has a small lumen, which may allow the tip of the probe. Its walls are thick and its lumen is small due to the enchroachment of the lymphoid projections of the submucosa.

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Figure 350 Showing positions of appendix

Figure 351 Showing development of apendix

Figure 352 Showing ileocolic opening (ileo-caecal)

Figure 353 Showing ileocaecal folds and the recesses

Position of Appendix:

It is known for its variable position and length. Its length varies from 3 to 30 cm, (normally range being 3-5 cm).

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Positions of the Appendix:

Retrocaecal Appendix: Pelvic (21%):

Subhepatic:

Post-ileal:

Position of the appendix is as under: 1. Retrocaecal - 75% 2. Subcaecal. - 1.5% 3. Paracaecal - 2% 4. Retrocolic - 1% 5. Preileal - 1% 6. Postileal - 5% 7. Pelvic. - 21% 8. Left sided appendix When pointing towards the pelvis it lies over the right psoas major muscle and the external iliac vessels. Extension of the hip gives pain in acute appendicitis (Psoas test). In pelvic position it lies on the obturator internus muscle and gives pain during flexion and the internal rotation of the right hip. In female appendix is an important relation of the ovary. Meso-appendix is small, triangular and incomplete fold of peritoneum. It is also known as mesentery of the appendix. The appendicular artery the branch of the lower division of the ileocolic artery runs behind the terminal ilium and enters the mesoappendix some distance away from the base of the appendix. It follows the free margin of the mesoappendix. Due to the short mesoappendix the appendicular artery lies on the appendix directly and gets embedded near the tip. The artery gets thrombosed leading to necrosis of the tip of the appendix which is followed by perforation and peritonitis (Gangrene means the death of a tissue with putrification super added). At the base of the appendix appendicular artery anastomoses with the posterior caecal artery. At times this anastomoses is larger and the surgeon has to be careful while crushing the appendicular stump. Retrocaecal: Position of the appendix is retrocaecal in more than 70% of the cases. It lies in retrocaecal recess. Due to the gas in the caecum, appendicular tenderness may not be felt at the Mc-Burney’s point. There is absence of rigidity in the right iliac fossa. However, the rigidity and tenderness is present in the right loin, due to the contraction of the quadratus lumborum muscle. As the tenderness and rigidity over the right iliac fossa are absent it is known as “silent appendix”. It is unfortunate that the commonest position of the appendix fails to demonstrate the most common signs. Commonest position of the appendix makes the signs and the symptoms of acute appendicitis are obscure. No wonder that it has been described as “Silent Appendix”. There is no abdominal rigidity and tenderness as the appendix is entirely intra-pelvic. When the tip of the appendix is in contact with rectum it causes diarrhoea. As it comes in contact with the obturator internus muscle. Flexion of the hip and the internal rotation of the thigh give pain. (Obturator test). It is due to non-descent of the ceacum in right iliac fossa. It remains in subhepatic position giving signs and symptoms which can be mistaken for the signs and symptoms of the acute cholicystitis. As the inflamed appendix is hidden behind the terminal ileum, there is no shifting of pain from umbilicus to the right ileac fossa commonly seen in appendicitis. It is a big challenge for the treating surgeon which is further aggravated by the presence of the diarrhea or passage of small quantity of

Small Intestine

In Infants:

In Pregnancy: McBurney’s Point:

Histology of the Appendix:

Development of Appendix : Anomalies of the Appendix :

Coecal Recesses:

Large Intestine:

Functions of Colon:

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stool after every each food and drink. As the inflamed, appedix irritates the terminal ileum. Some of the cases of missed appendix belongs to the group. Appendix in infants causes diffused, fulminating peritonitis due to short and poorly developed greater omentum which is commonly regarded as policeman of the abdomen. Uterus becomes the abdominal and pushes the appendix in the abdominal cavity amongst the coils of the intestine. It promotes peritonitis. Indicates the base of the appendix on the anterior abdominal wall. It lies at the junction of the lateral third and medial two-thirds of a line joining the anterior superior iliac spine and the umbilicus. It has a serous, muscular submucous the mucus coats. Muscular coat (outer longitudinal) is formed by union of the three taeniae coli at the base of the appendix (Taeniae coli are placed at interval in the ascending colon). Important feature of the organ is the presence of the large number of lymphoid collections in the submucous coat. Due to large store of lymphoid tissue appendix is regarded as the tonsil of the abdomen. Lymphoid projections reduce the cavity of the appendix to an extent that it can hardly admit the tip of the match-stick or a proble. Caecum and appendix develope from the caecal bud from the posterior arterial segments of the mid-gut. Right wall of the caecal bud grows faster and pushes the appendix medially. 1. Agenesis 2. Duplication 3. Left sided appendix. It is due to nonrotation of the gut. 4. Sub hepatic : ceacum fails to descend down into the right iliac fossa. They are three in number. 1. Superior ileocaecal recesses (Figure 353): It is placed between the caecum and the ascending colon and is limited in front by the superior ileoceacal fold which is vascular as it contains branch from the ileocecal artery. Its mouth is directed downwards and to the left. 2. Inferior ileocecal recess: It is present in the younger subjects only. It extends from the inferior part of the ileum to the mesoappendix. It is guarded by inferior ileocaecal fold. It does not contain blood vessel and is known as bloodless fold of Treves. 3. Retrocaecal recess: It is deep and lies between the posterior wall of caecum and the parietal peritoneum. It extends from caecum to the anus and divisible into following parts and its length is 1.5 metre: 1. Caecum 2. Ascending colon 3. Transverse colon 4. Descending colon 5. Sigmoid 6. Rectum 7. Anal canal. 1. Reception – It receives material from small intestine 2. Storage 3. Absorption 4. Manufacture of vitamin B. It is manufactured by the bacteria flora. Consumption of some antibiotics disturbs bacterial flora and causes staphyloccocal enterocolitis.

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Ascending Colon :

Posterior Relations (Figure 354):

5. Production of antibodies containing IgA group which has protective action against micro-organism. 6. Secretion of mucous for lubrication. Too-much loss of mucous amounts to loss of potassium (K) 7. Propulsion It is 15 cm in length. It extends from the caecum to the visceral surface of the liver, where it turns first to the front and then to the left, to form the right hepatic flexure. From below upwards: 1. Iliacus muscle. 2. Quadratus lumborum. 3. Lumbar fascia 4. Transversus abdominis. 5. Right kidney. 6. Ilioinguinal and ilio-hypogastric nerves. 7. Fourth lumbar artery.

Figure 354 Showing ascending colon

Anterior Relations:

Right colic Flexure: Transverse Colon:

Taeniae coli are arranged as under: 1. Anterior one 2. Posterior two. If the anterior taeniae coli is traced downwards it meets the base of the appendix. This is the method which is commonly used by the surgeons to locate the appendix. Greater omentum and coils of intestine are the anterior to it. Ascending colon has a peritoneal covering only from the front and sides presenting peritoneal gutters on either sides (Para-colic gutters). It is related the visceral surface of the right lobe of liver. Second part of duodenum and the fundus of the gallbladder lie on the antero-medial aspect of the flexor. It runs from the right colic flexure to the left colic flexure with a downward convexity. The left flexure is at a higher level than the right. It is about 50 cm long. It has a mesocolon except on the right where it lies in direct contact with the second part of the duodenum and the head of the pancreas. Its upper surface is related to the liver, gallbladder, greater curvature of the stomach and the spleen, from right to the left side. Posterior surface is related to the second part of duodenum, head of the pancreas, upper part of mesentery, duodeno-jejunal flexure and coils of the small intestine.

Small Intestine

Descending Colon (Figure 355):

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Left colic flexure is attached to the diaphragm by means of phrenico-colic ligament, which supports the lateral end of the spleen. Its length is about 25 cm. It occupies the left hypochondriac and the left lumbar regions. It meets the pelvic colon at the inlet of the true pelvis. It runs along the lateral side of the left kidney and forms a curve at the lower pole of the kidney and then descends downwards. Descending colon is covered with the peritoneum from the front and the sides. It presents peritoneal gutters, i.e. the left paraperitoneal gutter is continuous with the pelvic cavity making it easy for the infected material to reach the pelvic cavity.

Figure 355 Showing posterior relations of descending colon

Posterior Relations:

Pelvic Colon:

Course of the Loop of Pelvic Colon (Figures 356 and 357):

1. Left kidney. 2. Left psoas major and iliacus. 3. Left quadratus lumborum. 4. Left transversus abdominis. 5. Left subcostal vessels and nerve. 6. Left iliohypogastric and ilio-inguinal nerves. 7. Left fourth lumbar artery. 8. Left lateral cutaneous nerve of thigh. 9. Left femoral and genito-femoral nerves. 10. Left testicular or ovarian vessels and the external iliac artery. It is also known as sigmoid colon. It is hanged down in the left side of the pelvis through the inverted V shaped base of the pelvic mesocolon. It is 40 cm in length. Normally it is located in the pelvic cavity and extends from the pelvic brim to the third sacral piece to continue as the rectum. During first part of its course it runs along the left wall of the pelvic cavity. Second part is directed to the right and crosses the pelvic cavity ‘between the rectum and the urinary bladder in case of the male and bladder and uterus in case of the female. Its third part runs backwards to reach the median plane and at the middle of the third piece of sacrum it continues as the rectum. It has its own pelvic mesocolon. Root of the pelvic mesocolon is like a inverted V. In between the two limbs lies the recess known as the recess of the, pelvic mesocolon. It is important to remember that the left ureter is easily found at the apex of the recess.

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Figure 356 Showing loop of pelvic colon

Figure 357 White arrow points to the apex of sigmoid mesocolon showing ureter at the apex

Rectosigmoid Junction:

It is at the third sacral vertebra, the place where the pelvic meso colon ends. Angulation at the recto-sigmoid junction being acute, endoscopist may face a problem while passing the sigmoid scope. Little loss of concentration can perforate the bowel. Rectosigmoid junction lies at the distance of 15 to 17 cm from the opening of the anus.

Relations of the Pelvic Colon :

Lateral: 1. External iliac vessels. 2. Obturator nerve. 3. Vas deferens in male. 4. Ovary in female. 5. Lateral pelvic wall (left). Posterior: 1. Left sacral plexus. 2. Left internal iliac vessels. 3. Left ureter. 4. Left piriformis muscle. Inferior: 1. Urinary bladder in male. 2. Uterus and urinary bladder in female.

Small Intestine Clinical :

Hirsprung’s Disease: (Megacolon)

Acquired or Secondary Megacolon: Redundant Colon: Cathartic Colon : Blood Supply of Large Intestine (Figures 358 to 360): Nerve Supply of Large Intestine:

Figure 358 Showing marginal artery of Drummond

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Superior: Coils of small intestine. Sigmoid volvulus : Vovulus means rotation of the part of the gut around the axis. Following are the favouring causes of the vovulus of the sigmoid: 1. Narrow base of the pelvic colon. 2. Long pelvic mesocolon 3. Over loaded pelvic colon 4. Band of adhesion attached to the loop. If the sigmoid colon has taken ½ turn it can be corrected. When it takes more than 1½ turn in an anticlockwise direction it obstructs the blood supply and causes gangrene. Severe pain in abdomen and huge distension is seen. There is absolute constipation (absolute constipation means there is no passage of faeces or the flatus). Sigmoidoscopy is done and the tube is passed which may help in deflation of the sigmoid. This is followed by resection and end to end anastomosis of the affected segment of the colon. In this condition there is total absence of parasympathetic ganglion cells in the spastic segment. Pelvic colon is dialated and hypertrophy. Spastic part involves the rectum and the anal canal. The patient passes tooth paste like stool. Excision of spastic segment is done followed by an anastomosis. Note: Don’t wash the colon with water as it gets absorbed and causes water intoxication. (Use isotonic saline). It is due to the faecal impaction (Hard stool), fissure and spastic sphincter. Colon is dilated and hypertrophied up to anal canal. It is seen in neurotic females, in which colon gets elongated and patient has chronic constipation. Colon is dialated, immobile and the mucosa hooks black (Melanosis coli) due to the chronic use of purgatives. Blood supply of large intestine comes through the marginal artery. (Marginal artery of Drummond). It is an arterial arcade formed by the ileo colic, right colic, middle colic, left colic and sigmoidal branches. It lies within the frame of large intestine above 2 – 3 cm away and giving branches known as vasa-recti. Due to an excellent vascular arcade formed by the marginal artery, colon does not suffer in case of the block of one of the many feeding channels. Surgery of colonic resection follows the vascular

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Figure 359 Showing arrangement of taenia coli

Figure 360 Showing blood supply of large intestine

pattern and their demarcation strictly. Where the members of the marginal artery have poor anastomotic link or no link between them, is known as “critical point”. Superior mesenteric artery supplies the distal half of the duodenum, jejunum, ileum, caecum, appendix, ascending colon, hepatic flexure and right two thirds of the transverse colon. Inferior mesenteric artery supplies the left one third of the transverse colon, descending colon, sigmoid colon and the upper part of the rectum.

LYMPHATIC DRAINAGE OF LARGE INTESTINE

Nerve Supply of Large Intestine:

It goes to (i) epicolic, (ii) paracolic, (iii) intermediate and (iv) terminal. Epicolic nodes are on the wall of the colon, paracolic lie along the marginal artery anastomosis. Intermediate arc with right, middle and left colic arteries terminate nodes are associated with the trunks of the superior and inferior mesenteric arteries. Carcinoma of colon spreads through lymphatics and the three groups of nodes are associated with arteries. In order to prevent gangrene, surgeon has to stick to the vascular limits. Recall the embryology of the large intestine as the nerve supply sticks to the parts derived from the mid-gut and the hind gut, respectively. Parts derived from the mid-gut like caecum, ascending colon and right twothirds of the transverse colon get the parasympathetic supply from the

Small Intestine

Path of Visceral Pain:

Splenic Flexor:

Arch of Rolan:

Barium Enema:

Colonoscopy and Sigmoidosopy: Diverticulosis:

Diverticulitis: Carcinoma of the Colon:

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vagus. However, the left one-thirds of the transverse colon, descending colon and the sigmoid are supplied by the pelvic splanchnic nerve (S2,3,4). 1. Lesser splanchnic (T10T11) nerves carry visceral pain sensations from as ascending and transverve colon; hence referred in pain is felt at the umbilicus 2. Lumbar splanchnic nerves (L1 L2) carry visecral pain sensation from descending colon and sigmoid; therefore, referred pain from these parts of the colon is referred to the inguinal region. Splenic flexure is supplied by the left ileocolic branch of the inferior mesenteric artery and the middle colic branch of the superior mesenteric artery through marginal branches. The splenic flexure forms the junctional zone of the superior mesenteric and the inferior mesenteric arteries, making the flexure prone to ischaemia. It is the subsidiary channel connecting the main trunk of the middle coelic and the branch of the left colic arteries. In case of nondevelopment of the anastomotic channel, obstruction of one of the main branches results in ischemia of the splenic flexure. Ba enema is done in order to diagnose the diseases of the colon like carcinoma and ulcerative colitis. In carcinoma, obstruction of the lumen is seen by the growth. In ulcerative colitis loss of haustrations and straightening of the colonic wall are evident. They are done to study colonic mucosa with the help of colonoscope or sigmoidoscope. Care must be taken at the recto-sigmoid junction as the endoscopist has to negotiate junction to avoid colonic perforation. Diverticulosis is seen mostly in the sigmoid colon. Due to the high intraluminal pressure, colonic mucosa herniates through the colonic wall at the site of the entry of a blood vessel into the appendices epiploicae. It is important to remember that the recto-sigmoid junction is hardly 15 to 17 cm from the anal orifice. Inflammation of the diverticula is known as diverticulitis. Carcinoma of the colon grows slowly and encircles the colonic wall resulting in stricture of the colon, which causes obstruction. The spread of malignancy is initially through the lymphatics, however, in advance cases secondaries reach the liver through the portal vein. Carcinoma of the ascending colon including caecum and the ileocaecal junction is treated by right hemicolectomy. In in-operable cases an artificial opening is made in the transverse colon to relieve the obstruction. It is known as transverse colostomy.

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ABDOMINAL AORTA

Relations:

Figure 361 Showing abdominal aorta

Figure 362 Showing schematic illustration of anterior relations of abdominal aorta (diagrammatic)

It is the continuation of the thoracic aorta. It extends from the aortic opening at the level of 12th thoracic, to the level of the 4th lumbar vertebra. Here it divides into right and the left common iliac arteries. The point of division lies slightly on the left side of the mid-line. Anterior relations are: (Figures 361, 362 and 362A) 1. Coeliac artery and branches 2. Coeliac plexus 3. Lesser sac which intervens between it and the hepatic papillary process and 4. The lesser omentum 5. Superior mesenteric artery – crosses the left renal vein 6. Body of the pancreas, 7. Proximal part of testicular and ovarian arteries 8. Third part of duodenum, 9. Root of mesentery 10. Peritoneum 11. Coils of intestine.

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Figure 362A Showing abdominal aorta, coeliac ganglion, left renal vein and crossing of the left ureter by left testicular or ovarian artery. Inferior vena cava is at the 5th lumbar level under the right common iliac artery

Left Relations: Branches of the Aorta: Unpaired Branches:

Posterior relations: 1. Lower four lumbar vertebrae, 2. Inter-vertebral discs, 3. Anterior longitudinal ligament, 4. Left lumbar veins and four lumbar arteries, 5. Anterior border of the left psoas major muscle. Right relations: 1. Inferior vena cava and the right sympathetic chain, right coelic ganglion, which lies posterior to the inferior vena cava. 2. Right crus of the diaphragm, 3. Cisterna chyli, and 4. The azygos vein. Left crus of the diaphragm, Left coelic ganglion, duodeno-jejunal flexor, left sympathetic chain, inferior mesenteric vessels and coils of intestine. It has two sets of branches: 1. Paired and 2. Unpaired 1. Coeliac: Coeliac arises at the level of 12th thoracic vertebra and immediately divides into three branches, i.e. 1) Left gastric 2) Splenic and 3) Hepatic. 2. Superior mesenteric artery: Superior mesenteric arises at the level of first lumbar vertebra. It supplies distal 1/2 of duodenum, jejunum, ileum, caecum, appendix, ascending colon and right two-thirds of transverse colon. 3. Inferior mesenteric artery: Inferior mesenteric artery arises at the level of third lumbar vertebra. It is an artery of the third part of the gut and supplies the left one-third of transverse colon, colic flexure, descending colon, pelvic colon and the rectum. Aid to memory for inferior mesenteric artery (All three): 1. Artery of the third part of the gut (Hind-gut). 2. Arises at the third lumbar vertebra. 3. Lies behind the third part of the duodenum. 4. Median sacral: Median sacral arises from the back of the bifurcation of the abdominal aorta, gives 5th pair of lumbar arteries passes in

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5.

Paired Branches:

1. 2. 3.

4.

5.

front of the sacral promontory to continue in the hollow of the sacrum behind the rectum. Common iliac arteries: Aorta divides into two common iliac arteries at the level of 4th lumbar vertebra. After its origin from the aorta common iliac artery run downwards, obliquely and divides into two the internal and the external iliac arteries at the level of lumbosacral intervertebral disc. Right common iliac artery lies anterior to the formation of the inferior vena cava. Phrenic arteries: They give superior suprarenal arteries. Middle suprarenal arteries: They arise directly from the aorta. Renal arteries: They arise at the 1st lumbar level. Right renal artery runs to the right behind the left renal vein, the inferior vena cava, head of the pancreas and the right renal vein to enter the hilum of the right kidney. The left renal artery goes to the left behind the duodeno-jejunal flexure. Both the renal arteries give inferior suprarenal arteries and also supply the ureters. Testicular arteries (in males) and Ovarian arteries in female: They arise from the front of aorta near the origin of the renal arteries. Right testicular artery runs in front of the inferior vena cava and the right ureter. It enters the deep inguinal ring and passes through the inguinal canal with the spermatic cord. The left testicular artery crosses the left ureter and runs behind the descending colon. Ovarian arteries follow the same course case of female. Lumbar arteries: They are four in number and arise from the back of aorta. Fifth pair of arteries arises from the median sacral artery.

CLINICAL Aneurysm:

Embolism:

Surface Marking:

Aneurysm of the abdominal aorta appears as a pulsatile, palpable, painless swelling of the abdomen. It should be suspected even in the absence of abdominal pain, backache and pain in the thighs. Aortography, Ultrasound and CT scan is done as the diagnosis aids. In the absence of surgery 80% cases are dead within one year. Surgically aneurysm is treated by synthetic graft. Embolus from the heart in case of recent myocardial infarction is lodged at the bifurcation of the aorta leading to the ischemia of lower limbs and the gangrene. Leriche syndrome is due to chronic atherosclerosis of the distal aorta. It gives rise to claudication, pallor and the absence of femoral pulses. Blockage of internal iliac artery leads to impotance in males. Draw a thick line measuring 2 cm in breadth from a point 2.5 cm above the transpyloric plane to a point 1.2 cm below and to the left of the mid-point of the intercrestal plane.

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INFERIOR VENA CAVA

Relation (Figures 363 and 364): Figure 363 Showing inferior vena cava and its anterior and posterior relations (diagrammatic)

Figure 364 Showing boundries of aditus to lesser sac (schematic)

Inferior vena cava is the greatest venous channel draining blood of the lower half of the body. Inferior vena cava formed at the level of the 5th lumbar vertebra by the union of two common iliac veins. The point of formation lies below and to the right of the bifurcation of the abdominal aorta and is under the right common iliac artery. It runs upwards on the right side of the aorta up to the third lumbar vertebra. Above, it lies on the diaphragm and is separated from the aorta by the root of the right crus on the left. It lies in the groove on the posterior surface of the liver. Next it pierces the central tendon of the diaphragm at the level of 8th thoracic vertebra and enters the right atrium of the heart by piercing the fibrous pericardium. It conveys major portion of the blood from the body below the diaphragm to the right atrium. It has a valve at the opening in the right atrium. Anterior: Following structure form the anterior relations of the inferior vena cava from above downwards.

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Tributaries (Figure 366):

Common Iliac Veins:

1. Liver, 2. Aditus to the lesser sac, 3. Free margin of lesser omentum, portal vein common bile duct, and the hepatic artery. 4. First part of the duodenum, 5. Head of the pancreas, 6. Third part of duodenum, 7. Right testicular or ovarian artery. 8. Root of mesentery, peritoneum and coils of intestine, 9. Right common iliac artery. (It is formed under right common iliac artery.) Posterior: 1. Lower three lumbar vertebrae and the right lumbar arteries. 2. Right sympathetic chain, 3. Right psoas major muscle, 4. Right crus of diaphragm which itself is related to the following structure anteriorly and forms the posterior relations of the inferior vena cava. i. Right renal artery, ii. Right suprarenal, iii. Right phrenic artery, iv. Right coelic ganglion and v. Right middle suprarenal artery It has already been mentioned that the right ureter is on the right side of the inferior vena cava. 1. Lumbar veins: Except the first and second lumbar veins, others open into the posterior aspect of the inferior vana cava. First and second lumbar veins either join the third lumbar or go to the ascending lumbar vein. They may join the vena azygos on the right and the inferior hemiazygos on the left. Ascending lumbar is an anastomotic channel connecting iliolumbar, lateral sacral and the subcostal veins. It runs anterior to the roots of the transverse process of the lumbar vertebra. Ascending lumbar vein joins the subcostal vein to form the azygos vein on the right and joins the hemiazygos vein on the left. 2. Right testicular or ovarian veins: Please remember that the right testicular or ovarian vein drains into the inferior vena cava and the left testicular and ovarian vein drains into the left renal vein. 3. Renal veins: Left renal vein is longer than the right as it has cross the midline from left to the right. Left renal vein crosses in front of the abdominal aorta and its own artery i.e the left renal artery. As it crosses the abdominal aorta it is crossed by the superior mesenteric artery from the front and is sandwitches between the aorta behind and the superior mesenteric artery in front. Left testicular or ovarian vein opens in the left renal vein. Left suprarenal vein also opens in the left renal vein. It is important to remember this fact as in hypernephroma of the left kidney, left renal vein is obstructed by the malignant cells leading to the blockage of left testicular vein resulting in left sided varicocele. 4. Right suprarenal vein: It is the shortest vein and opens into the inferior vena cava lying anterior to it. 5. Hepatic veins: They are three in number, i.e. right, central and the left. They are of larger size and directly join the inferior vena cava. Their role in support of liver is important. They are formed by union of the external and the internal iliac veins in front of the sacroiliac joints. Left common iliac vein is longer as it has to

Inferior Vena Cava

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cross the mid-line. It crosses the median sacral artery superficially. Both the common iliac veins receive ilio-lumbar veins of the respective side, however, the median sacral vein joins the left common iliac vein.

CLINICAL Trauma :

Compression:

Collateral Channels (Figure 365):

Figure 365 Opening of collateral venous circulation in the event of obstruction of the superior and inferior vena cava

Wall of the inferior vena cava being thin is easily lacerated and bleeds profusely. It is invariably fatal in spite of the fact that the blood in the inferior vena cava is under low pressure. In view of the structures in front of the inferior vena cava like right subcostal arch, liver, duodenum, pancreas and the mesentery, surgical approach to the inferior vena cava is difficult. In pregnancy gravid uterus presses the inferior vena cava causing physiological varicose veins of the lower limb. On termination of pregnancy they disappear. Large retroperitoneal tumours obstruct the inferior vena cava and lead to venous congestion of the lower limb with opening of the collaterals as under. Superficial collateral channel between the lateral thoracic vein, the tributary of the axillary vein and the superficial epigastric vein, the tributary of the long saphenous vein is enlarged. Similarily the channel between the internal mammary thoracic and the inferior epigastric veins undergo enlargement. Azygos, lumbar and vertebral veins do take part in formation of collateral channels.

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Figure 366 Showing inferior vena cava and its relations

Caval-caval Shunt: Surface Marking:

Alternate pathway for the blood to reach the right atrium of the heart is known as caval-caval shunt. Mark a point below and to the right of a point where intertubercular and media plane cross. Second point is marked at the right 6th costal cartilage join the two points.

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LUMBAR PLEXUS It lies in the substance of the psoas major muscle. It is formed by the anterior primary rami of the L 1, L2, L3, and L4, nerves. Following branches are given from this plexus. 1. Ilio-hypogastric, ilio-inguinal and one root of the genitofemoral come from the first lumbar nerve. 2. L1 and L2 give lateral cutaneous nerve of the thigh. It runs on the iliacus muscle under the fascia iliaca and enters the thigh behind the lateral end of the inguinal ligament or may pass through it. (Meralgia Parasthetica) 3. Femoral nerve: Femoral nerve arises from the posterior divisions of L2, L3 and L4. 4. Obturator nerve: Obturator nerve arises from the anterior divisions of the L2, L3 and L4. It runs on the medial side of the psoas major and runs along the lateral wall of the pelvic cavity. Lumbosacral trunk is formed by the union of the L4 and whole of the 5th lumbar (Lumbosacral trunk is formed by all the lumbars and none of the sacral). (Figure 367) Figure 367 Showing lumbar plexus

Note: Psoas major muscle is related to three nerves, the obturator medially, the femoral laterally and the genito-femoral in front.

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COELIAC GANGLION

Cisterna Chyli:

It is the ganglion of a considerable size (2.5 cm in diameter) lying on the crura of the diaphragm on either side of the aorta. They communicate with each other through the nerve plexus which encircles the trunk of the coeliac artery. The ganglion is situated between the coeliac artery and the suprarenal gland. Right ganglion is under cover of the inferior vena cava, while the left is related to the splenic artery which crosses it from the front. Greater splanchnic and lesser splanchnic nerves join the coeliac ganglion. It gives branches to the suprarenal gland, and has a communication with the coeliac plexus. Present around the aorta and the superior mesenteric artery, are the fine sympathetic nerve plexuses. Coeliac plexus is also known as solar plexus. Sudden forceful blow in the epigastrium can stimulate the solar plexus and cause death. Cisterna chyli is a thin-walled fusiform dilation of the lymphatic sac lying over the first and second lumbar vertebrae. It is under the right crus of diaphragm. Thoracic duct begins from its cranial end. It is joined by the intestinal and the lumbar lymph trunks.

Diaphragm

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DIAPHRAGM

Openings of the Diaphragm:

Figure 368 Showing origin of diaphragm and its openings. Note the attachments of the medial and lateral arcuate ligaments (below)

Diaphragm is the great musculo-fibrous partition between the abdomen and the thorax. It arises from the vertebral column by the right and the left roots (crura). Right crus arises from the upper three lumbar vertebrae, while the left from upper two lumbar. The peripheral origin of the diaphragm is from lower 6th ribs where it interdigitates with the slips of the transverses abdominis muscles. It arises from the xiphoid process. It has ligamentus origin from the median, medial and the lateral arcuate ligaments. Fibres ascend in an arched fashion to form the right and the left domes of diaphragm. They are inserted into the central tendon of diaphragm which presents the median lobe with right and the left leaves. Crura are connected by the median arcuate ligament over the aortic opening. Medial arcuate ligament runs from the vertebral body to the tip of the transverse process of the first lumbar vertebra. Lateral arcuate ligament is attached to the tip of the transverse process of the first lumbar vertebra and the last rib (Figures 368 and 369). 1. Aortic opening: Aortic opening is situated at the lower border of the 12th thoracic under the median arcuate ligament vertebra. It gives passage to the aorta, thoracic duct and the azygos vein from the left to the right. 2. Oesophageal opening : Oesophageal opening is in the right crus of the diaphragm at the 10th thoracic vertebra and gives passage to the oesophagus and anterior and the posterior gastric nerves. Oesophageal branches of the left gastric artery also pass through the opening.

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Figure 369 Showing origin of diaphragm seen from below

3. Opening of the inferior vena cava: Opening of the inferior vena cava is at the junction of the right leaf and the central tendon of the diaphragm, at the level of the 8th thoracic vertebra. Inferior vena cava and the right phrenic nerve pass through it along with the few lymph channels from the liver. When the diaphragm contracts during inspiration it is pulled-down leading to an enlargement of the vena caval opening thereby increasing the venous return to the right atrium. 4. Vertebro-costal triangle : Vertebro-costal triangle is bounded by the lateral part of the last rib below, vertebral origin of the diaphragm medially and its costal origin of the diaphgram laterally. It is commonly present on the left. Abdominal contents may herniate through the gap into the thorax. 5. Openings of surgical importance: i. Foramen of Morgagni: (Larrey) Foramen of Morgagni is placed between the xphisternal and costal origins of the diaphragm. Transverse colon commonly herniates through the foramen of Morgagni. ii. Oesophageal opening (Figure 370): Oesophageal opening is in the right crus of the diaphragm. The right crus of diaphragm acts like a pinch cock, for the lower end of oesophagus. Lower part of the oesophagus with the stomach may herniate into the thorax through the oesophageal opening. Figure 370 Showing development of diaphragm

Hiatus Hernia :

iii. Foramen of Bochdalek: Foramen of Bochdalek lies on the left between costal and the vertebral origin of the diaphragm. It is due to the non development of left pleuroperitoneal membrane. Abdominal cotents may herniate into the thorax. In the absence of immediate surgical intervention, adhesions develop within hours and the infant dies due to respiratory distress. Hiatus hernia can be congenital, acquired, or the traumatic.

Diaphragm

Cardiac Sphincter:

Comment (Figure 371):

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Hiatus hernia is of three varieties. 1. Sliding 2. Para-oesophageal or rolling and 3. The mixed There is no anatomical sphincter at the cardiac end of the stomach. It is the pressure zone which prevents regurgitation of gastric contents into the oesophagus due to LOS, i.e. Lower Oesophageal Sphincter. Following factors are often credited for the sphincteric action: 1. Pinch cock action of the right crus of the diaphragm. 2. Angle between oesophagus and the stomach. 3. Folds of gastric mucous membrane. 4. Intra-abdominal part of the oesophagus which is subjected to intraabdominal pressure. 5. Oblique fibres of the stomach which increases an angulation between oesophagus and the stomach. More than 80% of the haital hernias are of sliding type. Due to gastrooesophageal reflux there is spasm and fibrosis of the oesophagus which pulls the gastro-oesophageal junction in the posterior mediastinum alongwith the stomach. Due to loss of gastro-oesophageal angle gastric contents enter the oesophagus (Regurgitation). In paraoesophageal type of hernia gastro-oesophageal junction does not shift and it is the stomach which passes by the side of the oesophagus into the hiatus and enter the posterior mediastinum. As the gastro-oesophageal angle is maintained gastric contents do not enter the oesophagus.

Figure 371 Showing para-oesophageal (rolling type of) hiatal hernia

Aid to Memory:

Investigation:

Symptoms of hiatus hernia can be remembered by the word HARD. H - Heart burn A - Anaemia R - Regurgitation D - Dysphagia In barium meal studies the table is tilted to 30° head down (Trendelenburg position) and in case the barium reflux is seen without pressure on the epigastrium the presence of hiatal hernia is confirmed.

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Nerves:

Four Intraperitoneal Spaces :

Blood Supply: Development of Diaphragm (Figure 370):

Recently in clinical surgery two abbreviated terms are in common practice. 1. GORD: Gastro Oesophageal Reflux Disease. 2. LOS: Lower Oesophageal Sphincter. Other openings : i. Between the sternal and costal origins of the diaphragm. Superior epigastric artery passes through. ii. The gap between the slips arising from the 7th and 8th ribs – gives passage to the musculophrenic artery. iii. Three splanchnic nerves pierce the crus of the diaphragm. iv. Inferior hemiazygos vein pierces the left crus of the diaphragm. Phrenic nerve is motor to the diaphragm (Root value : 3rd, 4th and 5th cervical). It is also supplied by the lower 6 intercostal nerves (probably sensory). Sympathetic fibres reach the diaphragm through the coeliac plexus. 1. Hiccough is due to the contraction of the diaphragm or the central medullary stimulation. 2. Inflammatory conditions of the visceral surface of the diaphragm give referred pain at the shoulder in the area of skin supplied by the supraclavicular nerves, the root value of the phrenic and the supraclavicular being the same. 3. Eventration of diaphragm: Eventration of diaphragm is due to the failure of development of the muscular part of the diaphragm. As a result, the thin fibrous diaphragm is pushed up into the thorax. 4. Damage to the phrenic nerve : Phrenic nerve avulsion was practiced in days when anti-tubercular drugs were yet to come. The process is known as phrenic nerve avulsion. As a result the hemidiphragm of that side goes up in the position of rest and stucks to the lungs, giving rest to the part of the lung by granting freedom from the respiratory movements. 5. Sub-diphragmatic spaces: Sub-diphragmatic spaces are four intraperitoneal and three extraperitoneal. The spaces are clinically important as they form the sites for collection of pus under the diaphragm. They are two on each side, one anterior and one posterior. Three extraperitoneal spaces, are two renal and one at the bare area of the liver. Out of these spaces the right posterior subdiaphragmatic space is important as it is the commonest site for collection of pus. It is known as Rutherford Morrison hepatorenal pouch. Note : Subdiaphragmatic abscess presents a clinical puzzle in cases of pyrexia of unknown origin. It is customary to say that “Pus some where/ Pus no where/ Pus under the diaphragm” Phrenic, musculophrenic and intercostal arteries supply the diaphragm. Diaphragm develops in the neck at the level of the 4th cervical segment from septum transversum and migrates downwards. The main root value of the phrenic nerves is C-4. Septum transversum drags the phrenic down in the thorax. In addition to the septum transversum diaphragm gets contribution from 1. Dorsal mesentery. 2. Right peritoneal membrane, 3. Left peritoneal membrane and 4. The body wall.

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PELVIS General Plan of the Pelvic Region:

Figure 372 Showing female pelvis

Figure 372A Showing constitution of pelvic wall. Note that sacral plexus is outside the pelvic fascia while the iliac vessels are inside

Two hip bones meet anteriorly to form the symphysis while, sacrum is interposed between the hip bones posteriorly. The cavity thus formed is divided into the false and the true pelvic cavities, by an arcuate line, which corresponds to the line of the brim of the pelvis. In erect posture the abovesaid line runs from the sacral promontary to the symphysis, obliquely downwards. Part of the pelvic cavity above and in front of this line is known as false pelvis and the part below and behind as the true pelvis. It may be remembered that the urinary bladder during childhood is an abdominal organ as the pelvis is not developed. In adults it is well inside the true pelvic cavity and rises into the abdominal cavity when distended. In case of the female, the uterus practically becomes the abdominal organ during later months of preganancy. These anatomical facts deserve a permanent place in your memory (Figures 372, 372A and 373). True pelvic cavity is bounded by the sacrum posteriorly, symphysis anteriorly and the parts of the hip bones below the arcuate line laterally. Sacro-tuberous and the sacro-spinous ligaments are present between the sacrum and the hip bones. They along with the bones mentioned form, the greater and the lesser sciatic foramina. Obturator foramen is closed by the

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Figure 373 Showing position of bladder in male with peritoneal reflection

Muscular Lining of the Cavity : Fascial Lining of the Cavity: Conventional Pelvic floor :

General Arrangement of the Pelvic Organs in Male: General Arrangement of the Pelvic Organs in Female: Reflection in the Male(Figure 373):

Peritoneum in Female (Figure 374):

obturator membrane. However, it is deficient in the upper part and leaves a space for the passage of the obturator vessels and the nerve. Greater and the lesser sciatic foramina are closed by the piriformis and the tendon of the obturator internus muscles, respectively. As regards the floor, the perineal membrane forms the major part. It is attached to the conjoint rami of the pubis and the ischium on either sides. Piriformis and the coccygeus line the posterior, the obturator internus lines, the lateral walls and the floor is formed by the sphincter urethrae and the deep transverse perineal muscles with the perineal membrane. The parietal layer of the pelvic fascia, forms the inner lining of the muscular pelvic walls. Well defined part of it in relation to the obturator internus muscle, is known as the obturator fascia. The levator ani and the coccygeus muscles form the pelvic floor. Pelvic surface of the muscular floor is covered with loose and ill-defined fascial layer. Spinal nerves and the sympathetic chains lie outside the fascial lining of the pelvic walls. On the other hand, the blood vessels of the pelvic cavity lie inside the fascial wall but outside the pelvic peritoneum. Space between the fascial wall and the peritoneum is filled with the extraperitoneal tissue which surrounds the pelvic organs. Rectum is situated posteriorly in the hollow of the sacrum and the urinary bladder along with the prostate and seminal vesicals lie behind the symphysis. Rectum is situated posteriorly in the hollow of the sacrum and the bladder lies behind the symphysis pubis. The uterus, tubes, cervix and the vagina occupy the middle of the pelvic cavity between the urinary bladder infront and the rectum behind. It must be remembered that the ovaries are placed on the lateral pelvic wall in the ovarian fossa. Pelvic peritoneum is described as an inverted umbrella. Peritoneum descends from the anterior abdominal wall to the superior surface of the urinary bladder. Further it covers upper part of the base of the bladder and runs posteriorly to lie in front of the rectum. It covers the upper 3rd of the rectum from the front and the sides, middle third only from the front. The lower one-third of the rectum is devoid of peritoneal covering. The fascia of Denonvillier lies anterior to the bare lower one third of the rectum. From the anterior abdominal wall peritoneum descends to the superior surface of the urinary bladder; from here it gets reflected over the anterior surface of the uterus at the level of the internal os. Thereafter it runs over the fundus of the uterus and covers the posterior surface of the body of the

Pelvis

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Figure 374 Showing general arrangement of the female pelvic organs with peritoneal reflection

Difference between the Male and Female Peritoneal Cavity: Pelvic Mesocolon (Figure 357):

uterus. It descends and covers the posterior fornix of the vagina and get reflected over the rectum. Due to the presence of uterine tubes the peritoneum forms a double fold which is known as broad ligament. Broad ligament extends from the side of the uterus to the lateral pelvic walls and from the tubes to the pelvic floor. Ovary is enclosed in the posterior layer of the broad ligament. The peritoneal fossa between the bladder and the uterus is known as ‘utero-vesical pouch’ and the fossa between the uterus and the rectum is known as ‘recto-uterine pouch.’ Female peritoneal cavity communicates with the exterior through the fibria and vagina. The peritoneum is modified to form the germinal epithelium in the region of the ovary. Due to exterior communication pelvic infections are more common in female. Attachment of the pelvic mesocolon is like an inverted ‘V’. The lateral limb of V begins on the medial side of the external iliac artery and runs upwards and medially upto the point of bifurcation of common iliac artery. Thereafter, its medial limb runs downwards and medially along the posterior wall of the pelvis to end in front of the third sacral vertebra. Mention of the recess of the pelvic mesocolon has already been made. It must be remembered that the left ureter lies under the peritoneal recess of the sigmoid mesocolon. Superior rectal artery runs downwards and medially to reach the rectum in the medial limb of the pelvic mesocolon.

MUSCLES OF THE PELVIC WALLS Piriformis:

Coccygeus:

Obturator Internus (Figure 375):

It arises from the pelvic surfaces of the second, third and fourth pieces of the sacrum, leaves the pelvic cavity through the greater sciatic foramen. It crosses lower part of the front of the sacroiliac joint enters the gluteal region and gets inserted into the tip of greater trochanter of femur. It is supplied by anterior primary rami of first and second sacral nerves. It lies just below the lower border of the piriformis. It arises from the spine of the ischium and runs medially for its insertion into the last piece of the sacrum and the first piece of coccyx. It may be noted here that the sacrospinous ligament is a degenerated part of the coccygeus muscle. It is a fan-shaped muscle which forms a muscular lining of the lateral wall of pelvis. It arises from the bony wall of the true pelvis around the obturator foramen and the obturator membrane. It leaves the pelvic cavity

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Obturator Fascia (Figure 375):

through the lesser sciatic foramen and gets inserted into tip of greater of the femur along with piriformis. It is supplied by the nerve to obturator internus muscle (L5, S1, and S2). It covers the obturator internus muscle and gets fused with the periosteum at its margin. Anteriorly it takes part in the formation of the obturator canal while inferiorly it fuses with the falciform process of the sacrotuberous ligament. In its middle it gives origin to the levator ani muscle. It has already been stated that the obturator fascia below the levator ani forms the lateral wall of the ischio-rectal fossa.

Figure 375 Showing obturator internus muscle and origin of levator ani from pelvic surface of body of pubis obturator fascia and pelvic surface of spine of ischium

Levator Ani Muscle:

Nerve Supply:

It forms the true floor of the pelvis and is covered on its pelvic surface by the parietal layer of pelvic fascia. It arises from pelvic surface of the body of the pubis, obturator fascia and the pelvic surface of the spine of the ischium. Fibres of this muscle are directed backwards and medially and get inserted into the perineal body, side of the anal canal, ano-coccygeal body and the coccyx antero-posteriorly (Figure 376). On its pelvic surface it is supplied by the branches of lower sacral and coccygeal nerves, while its perineal surface is innervated by the inferior haemorrhoidal nerve.

Figure 376 Showing parts of levator ani seen from below

Action:

Sphincter Urethrae Muscle:

Normally both the levators act together. The muscle helps in rising the intra-abdominal pressure. It acts during defaecation, forced expiration labour and vomiting. Fibres inserted into the anal canal help in pulling the canal upwards during the passage of faeces downwards. The fibres which form sling between the rectum and the anal canal help in keeping the rectal contents in the rectum. In case of the female anterior borders of the muscle help the tightening of the vaginal canal. Levator ani plays an important role in second stage of the labour. Sphincter urethrae muscle has already been described in the deep perineal pouch.

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Figure 377 Showing levator ani muscle seen from below

Pelvic Fascia:

Visceral Pelvic Fascia:

Rectum: Introduction:

Peritoneal Relations of the Rectum (Figure 378): Flexures of the Rectum (Figure 378 and 381A):

Pelvic fascia is divisible into two (1) parietal and (2) visceral. The main function of the parietal layer is to close the bony outlets of the pelvic wall. The obturator fascia is part of the parietal fascia similar to the fascia covering the piriformis muscle. As the name indicates it is the layer of connective tissue covering the pelvic organs. In general it is thin and negligible over the organs which are required to distend. (Visceral layer of pelvic fascia over the bladder is thin). Rectovesical fascia forms an important part of the visceral pelvic fascia. Superiorly it is attached to the peritoneal fold of the rectovasical pouch, and lower down it meets the perineal body (Fascia of Denonvillier). It is considered as a remnant of the peritoneal fold between the rectum and the bladder which descends almost to the pelvic floor during embryonic life. However, this view is not agreed upon by all. Visceral layer of pelvic fascia is extremely thick and forms a dense capsule or membrane over the organs which are not required to distend (e.g.sheath of the prostate). It is the part of the hind-gut between the sigmoid and the anal canal. Rectum means straight. It is straight in lower animals, children and old persons. Its length is 12 cm and has a diameter of 4 cm, i.e. equal to the diameter of the sigmoid. It must be noted here that 90% growths of the rectum upto 12 cm can be detected by gloved finger. It begins at the middle piece of the third sacral vertebra and runs downwards with a forwards corresponding to the concavity of the sacrum (sacral curvature). Lower down it goes backwards and downwards to continue with the anal canal, this flexure is known as perineal flexure. The level of the perineal flexor corresponds to the apex of the prostate in the male. Rectum ends, 2.5 to 3 cm in front and below the level of tip of the coccyx where the anal canal begins (Figure 381-A). 1. Upper 1/3rd is covered by the peritoneum from the front and the sides. 2. Middle 1/3rd the peritoneum only from the front. 3. Lower 1/3rd has no peritoneum covering at all. Flexures of the rectum are divided into two: 1. Anteroposterior 2. Transverse Anteroposterior curvatures of the rectum are sacral, which follows the concavity of the sacrum and the perineal where it turns downwards and backwards at the pelvic floor.

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Figure 378 Showing Peritoneal relations of rectum and valves of Houston

Transverse curvatures are three in number out of which two convex are to the right upper and the lower and the middle one is convex to the left. Rectum presents a dilatation known as ampulla of the rectum. The gross differences between the rectum and sigmoid colon are given as under: Sigmoid colon

Rectum

1. Presents sacculations.

1. No sacculations.

2. Presents appendices epiploicae.

2. No appendices epiploicae.

3. Presents a mesentery (mesocolon).

3. No mesentery.

4. Taeniae coli arranged in three bands. 4. Taeniae coli are arranged only in two wide muscular bands of which one lies in front and other behind. 5. Peritoneum is intimately attached to the organs.

Mucosal Folds:

5. Peritoneum wherever present is loosely attached to the organs.

Interior of the rectum presents two types of folds, i.e. temporary and permanent. Temporary folds are longitudinally placed folds of the mucosa. They disappear on distension of the rectum. Horizontal folds are formed by the mucus membrane and the circular muscle coat of the rectum. They are three in number (valves of Houston’s). The most constant is the middle fold which lies immediately above the ampulla of the rectum. Upper fold lies at the upper end of the rectum and is mostly attached to the right wall. Lower fold is attached to the left wall and lies 2.5 cm below the middle fold. The middle horizontal fold which is located above the ampulla of the rectum is constant. It is attached to the anterolateral wall of the rectum. It is the largest fold. During sigmoidoscopy, these folds may obstruct the passage of the sigmoidscope. Note: Sigmoid is the store house of faecal matter, from which the faecal matter enter the rectum. Collection of the faecal matter in the upper part of the rectum leads to the distension of the rectum initiating the reflex of the defaecation. Normally rectum is empty. Rectum is divided into two functional parts above and below the middle fold. Upper part can distend freely due to the peritoneal covering. Lower part of the rectum is normally empty except in those who are chronically constipated persons and the dead. Lower part of the rectum and the anal canal acts as the passage (door) while the upper part of the rectum acts as an anti-chamber to the store house of faecal matter, i.e. the sigmoid.

Pelvis Relations of Rectum in Male and Female: (Figure 379)

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Title

Male

Female

Anterior

Urinary bladder, seminal vesical, ureters, posterior surface of prostate, urethra, Ampulla of vas deferens.

Pouch of Douglas uterus, cervix, vagina.

Posterior Three pieces of sacrum, coccyx, piriformis, coccygeus, levator ani muscles, median sacral vessels, sympathetic chains, ganglion impar, sacral nerves, 234 coccygeal-1, - Pelvic splanchnic nerve - Fibro-fatty tissue. - lymph nodes

Three pieces of sacrum, coccyx, piriformis, coccygeus, levator ani muscles, median sacral vessels, sympathetic chains, ganglion impar, sacral nerves, 234 coccygeal-1, - Pelvic splanchnic nerve - Fibro-fatty tissue. - lymph nodes

Figure 379 Showing anterior and posterior relations of rectum in male (lower 1/3) (left). Anterior and posterior relations of rectum in female (lower 1/3) (right)

Supports of the Rectum (Figures 380 and 381):

Figure 380 Showing some of the posterior relations of rectum

Figure 381 Showing anorectal angle maintained by puborectalis part of lavator ani (left). Perineal body is anterior to the anal canal and the anococcygeal body posterior (right)

1. Course of the rectum itself: As it is straight in childrens and old the incidence of rectal prolapse is more. 2. Levator ani muscles: It virtually lifts the rectum up. (puborectalis part of the muscle). 3. Lateral rectal ligaments: They are formed by the condensation of the pelvic fascia along the middle rectal vessels and attach the rectum to the postero-lateral wall of the true pelvic cavity. 4. Perineal body and perineal muscles. Role of the perineal body is important as the perineal muscles are attached to it. The perineal body is essential for their effective contractions.

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Structure of the Rectum:

Blood Supply of the Rectum (Figure 382 and 383):

Figure 382 Showing origin of middle and inferior rectal arteries. Note origin of median sacral artery from aorta near its bifurcation

5. Waldeyer’s fascia: It extends from the lower part of the sacrum and the upper part of the coccyx posterior to the ampulla of the rectum. Condensation of the deep fascia behind the rectum forms this ligament. However the important role of the fascia of the Waldeyer is to prevent local spread of the carcinoma of the rectum than forming one of the components of the support. 6. Fascia of Denonvillier’s: It extends from the rectovesical pouch to the perineal body separating the rectum from the prostate and seminal vesical anteriorly. Role of the fascia of Denonvillier in forming the supports of the rectum, if any is poor. Like the fascia of Waldeyer its main role is to prevent local spread of the carcinoma of rectum. 7. Surrounding organs 8. Intra-abdominal pressure. It is made of five coats: 1. Serous, 2. Fascial, 3. Muscular, 4. Submucous, and 5. Mucous. Serous coat is incomplete and the outer lognitudinal layers of the muscular coat are grouped in the form of two muscular bands placed in front and behind the rectum. Four arteries supply the rectum. 1. Superior rectal artery – It is the continuation inferior mesenteric artery. 2. Middle rectal artery – It is a branch of anterior division of internal iliac artery. 3. Inferior rectal artery – It is the branch of internal pudendal artery. 4. Median sacral artery– It is the branch of the aorta at its bifurcation. 1. Superior rectal artery: (Figure 383) It is the continuation of the inferior mesenteric artery and is the main and important artery supplying the rectum. It divides into two branches right and the left at the level of middle of the third piece of the sacrum. The right branch further divides

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Figure 383 Showing blood supply of the rectum

Middle Rectal Artery: Inferior Rectal Artery: Venous Drainage:

Lymphatic Drainage of Rectum:

Nerve Supply of Rectum:

into anterior and the posterior branches. Tributaries of the superior rectal vein are also arragned in three sets, two on the right and one on the left. They are the sites for the internal haemorrhoids. It arises from the anterior division of the internal iliac artery and runs in the lateral ligament of the rectum. It divides into small terminal branches. It arises from the internal pudendal artery in the Alcock’s canal and jumps to the inferior surface of the levator ani and passes through the arched roof of the ischiorectal fossa to reach the anal muscles. Haemorrhoidal veins drain the upper part of the anal canal above the dentate line. As they go upwards they are known as rectal veins. They join to form the superior rectal vein. Superior rectal vein becomes the inferior mesenteric vein and joins the splenic vein. Splenic vein joins the superior mesenteric vein to form the portal vein. Middle rectal vein is small and becomes important only in the presence of block. They go to two groups of lymph nodes: 1. Pararectal nodes of Gerota: They are at the posterior aspect of the ampula above the levator ani muscle. 2. Middle rectal nodes: They are with the middle rectal vein and drain into internal iliac group of nodes. Removal of the middle rectal nodes is an important step according to the Japanese surgeons. The tendency of spread of cancer of rectum is mostly in the upper direction resulting in limited lateral and downward spread. Therefore the surgeon’s aim is to remove large number of proximal nodes. In case of the block of the upper lymphatic flow, metastasis occurs in the nodes associated with middle rectal vein and even may go to the superficial inguinal lymph nodes. Sympathetic L1 L2

Parasympathetic S 2 3 4

Inhibitory to the rectal muscles.

Motor to the rectal muscle.

Motor to the sphincter.

Inhibitory to the sphincter.

Pain sensations are carried by the sympathetic and the parasympathetic

Pain sensations are carried by the sympathetic and the parasympathetic Sense of distension of the rectum passes through parasympathetic

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Clinical:

Rectal Injuries:

Rectum and Appendicitis (Figure 384):

Per-rectal Examination (PR):

1. Valves of Houston particularly one above the ampulla is constant and it has to be compromised while doing sigmodoscopy. 2. Lymphatics of the rectum has tendency to go upward to the pararectal nodes of Gerota. 3. Carcinoma of rectum is of the adenocarcinoma variety. 4. Fascia of Denonvillier lies between the rectum behind and the prostate in front. It helps in prevention of local spread of rectal cancer. 5. Fascia of Waldeyr lies between the lower part of the sacrum and coccyx posteriorly and rectum anteriorly. It also helps in prevention of local spread of cancer of rectum. 1. Bleeding per rectum: Bleeding per rectum is the commonest and the most alarming sign of the rectal disease mostly as the result of internal haemorrhoids. Commonest cause of bleeding per rectum in children is hard stool. Dangerous and life threatening cause of bleeding per rectum in children is the intussusception. 2. Prolapse of Rectum: (Figure 383) Prolapse of rectum is of two types, partial and the complete. The rectum prolapses through the anal canal. In partial prolapse it is only the mucus membrane and the submucosa of the rectal wall which come out, while in the complete prolapse whole thickness of the rectal wall prolapses through the anus with its musculature. Prolapse of rectum occurs as a result of weakness of the muscle levator ani due to repeated child birth injuries in female. 3. Carcinoma of rectum: Carcinoma of rectum is an adenocarcinoma and is common in female. In 90% of the cases the growth can be felt with a gloved finger. It has tendency to go upwards. Local circumferential spread takes six months to occupy 1/4 of the circumference. It takes two years to complete the circle. Initial spread of the cancer of the rectum is through the local lymphatics, blood spread occurs later which is followed by the venous spread to the liver through the superior rectal vein. As we know that the superior rectal vein continues as the inferior mesenteric vein, joins the splenic vein and forms the portal vein. This explains the occurrence of metastasis of the carcinoma of the rectum in the liver. Local spread can be well imagined by the students of anatomy if he/ she revises the relations given in Figure 379 which are purely schematic. As we know the upper 2/3rd of the rectum has a partial peritoneal covering hence the injury of the rectum in upper 2/3rd has peritoneal involvement. It is treated like colonic injury by doing colostomy. Injury of the lower 1/3rd of the rectum is extraperitoneal which is treated by doing temporary cholostomy which is followed by rectal repair. When the inflamed pelvic appendix comes into the contact with the rectum, the patient has diarrhea. In per-rectal examination tenderness is felt in the pelvic peritoneal fossa on the right side. Other investigations for carcinoma of rectum: 1. Ultrasonography with a probe in rectum. 2. C.T.Scan. 3. X-ray of the chest for evidence of hepatic metastasis. It is done by putting an index finger of one hand in the rectum and other hand on the anterior abdominal wall one can feel the anterior rectal wall when the urinary bladder is empty (Bimanual palpation).

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Figure 384 Showing prolapse of rectum through posterior vaginal wall and through the anal canal. Also note herniation of bladder through anterior vaginal wall. Urethrocoele is also been

Per Vaginal Examination (PV): Comment:

One Can Say: Treatment of Carcinoma of Rectum:

Classical Presentation of Carcinoma of Rectum: Loss of Weight: Clinical Diagnosis:

Special Investigations: Barium Enema: Development of Rectum:

In female anterior wall of the rectum can be palpated by putting one finger in the vagina and the other in the rectum. Amongst colonic carcinoma, rectum heads the list as its incidence is around 38 to 40% while the carcinoma of the anal canal is at the bottom of the list its incidence being only 2%. Carcinoma of the rectum rides the list of the horse back of all the colonic carcinomas while the anal canal holds the tail. Treatment of carcinoma of rectum is known as abdominoperineal resection. 1. The aim of surgery is to achieve radical resection of the rectum along with the lymph nodes in the drainage area. 2. Second aim is to establish gastrointestinal continuity 3. Third aim is to preserve the anal sphincter. In abdominoperineal resection one surgeon does the clearance of the anal canal from below and the other works through the left paramedian or midline incision of the anterior abdominal wall from above. Patient goes to toilet before expected time and passes only blood and mucus if he has the carcinoma rectum. Radiating pain in the back occurs due to involvement of the sacral plexus, urinary bladder and the prostate. Loss of weight occurs when the patient has hepatic metastasis. Abdominal examination may show presence of ascitis and enlarged liver. In examination, nodular or ulcerating growth can be palpated with the gloved finger per rectally. Proctosigmoidoscopy, biopsy through rectoscope. Barium enema may show synchronus carcinoma of the colon. Bleeding per rectum is the earliest sign and do not forget that the piles and cancer can co-exists. Cloaca gets divided into two chambers, the urogenital sinus and the primitive rectum by the transversly placed urorectal septum. Urogenital sinus lies in front and the primitive rectum behind. When the urorectal septum fuses with the cloacal membrane, the latter is divided into two, the anterior urogenital membrane and posterior anal membrane. Before fusion of the urorectal septum with the cloacal membrane, the urogenital sinus and the primitive rectum communicate with each other. An ectodermal depression appears below the anal membrane. It is deepened by the mesenchymal tissue forming the lower half of the anal canal. Upper half of the anal canal is endodermal in origin and the lower half, ectodermal. As the anal membrane appears, two parts of the anal canal communicate. Site of the anal membrane is marked in adults by a pectinate line. Endodermal cloaca forms the rectum.

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ANAL CANAL Anal Canal :

Relations (Figure 385):

It is the terminal part of the alimentary canal having length of 3.8 cm. It begins where the rectum ends. It makes an angle with the rectum and is directed posteriorly to open as the external anal orifice which is placed 4 cm infront and below the tip of the coccyx. Its anterior wall is shorter than the posterior wall. Normally its lumen is collapsed as the anterior and the posterior walls are approximated except during the defecation. The collapse of the anal canal is due to the levator ani muscles and the sphincters of the anal canal. Anterior relations in male : 1. Perineal body, 2. Membranous part of urethra, 3. Bulb of the penis.

Figure 385 Showing peritoneal reflection in male and perineal flexure

Anterior relations in female: It is related to the lower part of vagina. Posterior relations in male and female: Tip of the coccyx and anococcygeal body.

Interior of the Anal Canal: Figure 386 Showing interior of the anal canal

Lateral relation in male and female: (Figure 386) Ischiorectal fossae and anal sphincters. Mucous membrane of upper part of anal canal is thrown into vertical folds numbering about 6 to 10 known as anal columns. (Columns of Morgagni). Lying within the column is the terminal branch of superior

Anal Canal

Clinical (Figure 387):

661

rectal artery and the venous tributary. The blood vessels are more in number at three places: 1. At the left lateral, 2. Right lateral and 3. The right anterior. These are the sites for the piles and are described as internal haemorrhoids. Two adjacent columns are connected by the fold in the lower part. They are known as anal valves (valves of Ball) and the pockets formed by them on their superior surfaces are known as anal sinuses of Morgagni. Being a pocket, infected material, gets lodged in the anal sinus. Sometimes an anal valve is torn by the hard descending mass of faeces forming an anal fissure. Lying at the level of the anal valves is the pectinate line or dentate line. Above the dentate line the epithelium is columnar, nerve supply is autonomic and the circulation is portal. Below the dentate line epithelium is squamous, nerve supply is somatic and circulation is systemic. It is considered to be the junctional zone between the portion of the anal canal developed from the endoderm and the ectoderm. Upper half of the anal canal is lined by pseudostratified columnar epithelium therefore carcinoma of the upper half is an adenocarcinoma. While the lower half of the anal canal is lined by squamous epithelium and hence its carcinoma is squamous cell carcinoma.

Figure 387 Anal canal

Musculature of the Anal Canal :

Small epithelial nodules are seen along the pectineal line. They are considered to be the remnant of the anal membrane. Immediately below the anal valves lies a transitional zone and at the lower limit at the transitional zone lies the white line. The white line is exactly at the level of intersphincteric groove which can be felt with the finger. The anal canal below the white line is covered with the true skin which is pigmented and has hair in the male and has sweat and sebaceous glands. 1. Internal sphincter is formed by circular coat of the rectum and is not under control of will (involuntary). It extend from upper end of the anal canal to the white line of Hilton. It surrounds the upper three fourth of the anal canal. Its spasms or contraction play an important role in anal fissures. 2. Longitudinal muscle of the rectum decend downwards external to the internal sphinctor. It fans out in the form of fibroelastic septae lower down and get attached to the perianal skin after passing through the external sphincter. This provides path for infections to spread and compartments for collection of pus.

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External Sphincter (Figure 388):

External sphincter is voluntary and is divided into three parts, i.e. subcutaneous, superficial and the deep. It covers the whole of the anal canal. The subcutaneous part lies below the internal sphincter. It is supplied by the inferior rectal nerve and the perineal branch of the 4th sacral.

Figure 388 Showing coronal section of anal canal

Anorectal Ring:

Blood Supply of Anal Canal: Venous Drainage:

Anorectal ring is the muscular ring formed by the internal sphincter and the lavator ani muscle and deep part of the external sphincter. The ring is situated at the distance of 2.5 cm from the anal margin. And demarcates the site of junction of the rectum and the anal canal. The ring can be felt by the flexed index during per-rectal examination. The ring is well developed posterolaterally than anteriorly, basically due to the absence of fibers of lavator ani. Division or disruption of the anorectal ring, done surgical, leads to incontinence. Anal canal is supplied by the superior rectal artery above the pectinate line and by the inferior rectal artery below. The internal venous plexus is situated in the submucosa of the anal canal. It has connection with superior rectal, middle rectal and the inferior rectal veins. The internal venous plexus forms the clinically important site of porta-systemic anastomosis. One would expect development of piles in case of portal hypertension, however the incidence of piles in portal hypertension is too low.

CLINICAL Piles (Figures 389 and 390):

They are the enlarged, elongated and tortuous tributaries of the superior rectal vein. The tributaries are located at 3, 7 and 11 O’clock positions. They are formed according to the branching pattern of the superior rectal artery which divides into right and the left branches in the middle of the third piece of sacrum. The right branch divides further lower down into the anterior and posterior branches. The hemorrhoids are covered with mucous membrane and are known as internal piles. The mucus membrane of this part is supplied by autonomic nerves hence painless but are sensitive to stretch. Superior rectal vein is valveless and the tributaries of the superior

Anal Canal

663

Figure 389 Showing internal and external piles (schematic)

Figure 390 Showing positions of the primary piles in lithotomy position

Piles of Pregnancy:

External Haemorrhoids:

Treatment of Piles:

Anal Fissure:

rectal veins are under pressure and are also pinched by the contraction of the rectal muscles, particularly during defecation. Patients suffering from chronic constipation develops haemorrhoids. Absence of valves in the superior rectal vein and its tributaries and the erect posture contributes to the formation of the piles. We are paying the price for the erect posture in the form of piles. During pregnancy the pressure of the uterus on the superior rectal veins results in hemorrhoids. Note: A patient of carcinoma of the rectum may present with bleeding piles. They are the elongation, dilatation and tortuousities of the tributaries of the inferior rectal vein. They are covered with skin and the skin has somatic nerve supply hence painful. External haemorrhoides can be associated with internal haemorrhoides and they are known as internoexternal piles. Cirrhosis of liver can result in haemorrhoides due to portal hypertension, however the incidence is very low. Piles are treated by 1. Injection of sclerosant. 2. Banding by elastic bands 3. Cryosurgery by application of liquid nitrogen. 4. Photocoagulation by infrared 5. Ligation and excision. The anal fissure is an ulcer in the long axis of the lower part of the anal canal following the tear of the anal valve and is very painful. The fissure is usually located dorsally in the midline ninety degrees. It is probably due to the fact that the superficial part of the external sphincter does not surround the anal canal posteriorly. Fissure is of two types: acute and

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Fistula in Ano:

Goodsall’s Rule:

Hidradenitis Suppurativa: Melanoma of the Anal Canal: Perianal Haematoma:

Microscopic Anatomy of the Anal Canal:

Special Note:

Pubo-rectalis: Anorectal Ring:

Fascia of Denonvillier: Waldeyer’s Fascia:

Lymphatic Drainage of Rectum and Anal Canal:

chronic. Chronic fissure has fibrous tissue in the floor and the cutaneous tag at the lower end. It is known as the sentinal pile (Sentinal means a guard). Fistula in ano is a tract lined by the granulation tissue connecting the anal canal or the rectum internally and the skin externally. When the tract is blind it is known as sinus. Fistula in ano is an outcome of anorectal abscess. It could be subcutaneous, submucous, low anorectal, high anorectal. The pelvi-rectal type of fistula is above the ring. Fistula placed in the anterior half of the anal canal is straight and the one situated in the posterior half is curved (horse-shoe fistula). It may have multiple external openings but has only one internal opening. The horse shoe shaped fistula is due to the fact that both the ischiorectal are connected posteriorly. In India multiple external opening are commonly seen in tuberculosis and one should never forget to ask for the X-ray of the chest. It is as the result of chronic infection of the apocrine glands around the anal area. It arises from the skin of the anal canal. It ulcerates and becomes black. It should be excised along with 2.5 cm normal area with bilateral block dissections of the superficial inguinal group of lymphnodes. Anal veins are radially placed around the anal verge and have connections with the inferior rectal vein and the internal rectal plexus. They rupture during straining at the time of defaecation leading to the formation of perianal haematoma which is very painful. Anal canal presents three zones from above downwards, each having length of 15 mm, 15mm and 8 mm. 1. Upper 15 mm zone has stratified columnar epithelium, 2. Middle 15 mm zone has stratified squamous epithelium, and presents no sebaceous or sweat glands and has no hair follicles. 3. Lower 8 mm zone is formed by the true skin having sweat glands, sebaceous glands and the hair follicles. Carcinoma of the anal canal has similar symptoms like that of fissure. The history is long and the victim is women, excision of the fissure and its biopsy is the wisest step. A part of the levator ani and the external sphincter play an important role in anal continence and process of defacation. Rectal or vaginal prolapse can occur due to their combined weakness. It lies at the junction of rectum and anal canal. It is formed by puborectalis, deep external sphincter, longitudinal muscule coat and the highest fibres of the internal sphincter. The division of the ring results in permanant incontinence. Fascia of Denonvillier is the fascial septum between the prostate infront and rectum behind running from the floor of the rectovesical pouch to perineal body below in male. Waldeyer’s fascia lies behind the rectum and in front of lower part of sacrum and coccyx. It is attached to the last two pieces of sacrum and coccyx posteriorly and the rectum anteriorly. They are surgically important as the fascia of Denonvillier and the fascia of Waldeyer both prevent the local spread of rectal carcinoma. Lymph channels from the rectum and anal canal go to the lymph nodes known as nodes of Gerota or pararectal nodes. They are at the rectal ampulla. Other set of vessels go to the internal iliac lymph nodes. From both the groups of lymph nodes, lymphatics go to lower aortic group of

Anal Canal

Pruritus Ani:

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nodes. The lymph vessels from the lower part of anal canal drain into the superficial inguinal lymph nodes (medial group). It may be recalled once again that the rectum and the upper part of anal canal get their nerve supply from the pelvic splanchnic nerves, while the lower part of anal canal is innervated by inferior haemorrhoidal nerve (somatic). This part of the anal canal is sensitive to pain, therefore during injection of sclerosant, the needle should never be put in the part of the skin as it is painful. It is associated with intractable iching around the anus. Skin around the anus become moist, red and cracked. Causes of pruritus are described by a classical mnemonic in surgical textbooks, e.g. mnemonic of five P’s as under: 1. Pus 2. Polyp 3. Piles 4. Parasite, and 5. Psyche. Note: Melanoma of anal canal. It must not be forgotten as the lower 8 mm of the anal canal is covered with true skin having sweat, sebaceous gland, hair follicles and the cells containing melanin pigments. Melanoma of anal canal arises from epidermal melanocyte lower part of the anal canal and metastases to the superficial inguinal nodes of both sides.

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URINARY BLADDER

Position of the Urinary Bladder (Figure 391):

Urinary bladder is the hollow muscular organ for the storage of urine. It is placed in the true pelvic cavity, when empty. It is situated between symphysis pubis infront and the rectum behind in males. In case of the female vagina with the intravaginal portion of the cervix is interposed between the bladder and the rectum. Normal, capacity of bladder is about 250 c.c. to 300 c.c. (in adults). It presents base, an apex, superior surface and two infero-lateral surfaces. Neck of the bladder is pointing downwards. Prostatic part of the urethra begins at the neck of the urinary bladder and enter the prostate. Anteriorly it is related to the retropubic space (cave of Retzius.) When distended, bladder rises in the abdomen. It comes in contact with the anterior abdominal wall lifting the peritoneum. In case of the children bladder is entirely intra-abdominal organ as the pelvis is yet to develop.

Figure 391 Showing position of bladder and some of its relations

Shape of Bladder: Neck:

Apex :

Superior Surface:

Running from the anterior aspect of the neck of the urinary bladder and the upper part of the anterior surface of the prostate are the medial and lateral puboprostatic ligaments. They are attached to the back of the pubis. The ligaments anchor the neck of the bladder to the pubis and do not allow the neck to rise higher up. Puboprostatic ligaments are closely related to the venous plexus laterally. It is like a 3 sided pyramid. Relations of the bladder: It lies 2.5 cm behind the symphysis pubis and is related to the prostate in case of males. Anteriorly it is connected to the symphysis by means of medial and lateral puboprostatic ligaments. In female the neck of the bladder is attached to the pubis by means of the pubovesical ligaments. In males ejaculatory ducts are at the back of the neck of the urinary bladder. (Figure 392) Apex lies behind the upper border of the symphysis pubis and is hardly placed at the depth of 2.5 cm from the skin of the anterior abdominal wall. It is connected to the umbilicus by means of median umbilical ligament which is the remnant of urachus. The surface of the urinary bladder has a complete peritoneal covering. Ureters join the bladder at the posterolateral angles of the bladder.

Urinary Bladder

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Figure 392 Showing urinary bladder as seen from below

Inferolateral Surfaces (Figures 396 and 397): Base of Bladder (Figures 393 and 394):

Cavity of the Bladder (Figures 398):

Figure 393 Posterior surface of bladder

Umbilical arteries run along the lateral borders of the superior surface. In males coils of intestine and the pelvic colon are related to the superior surface. In females the uterus and the coils of intestine are related to the superior surface of the urinary bladder. They are not covered with peritoneum and are related anteriorly to the retropubic space and retropubic pad of fat. Posterior part of the infero lateral surface is divided into the upper and the lower parts. Upper one is related to the obturator internus and lower to the levator ani muscles. It is described as the posterior surface of the urinary bladder. Ureters join the bladder at the lateral angles. In case of the male small area of the upper part of the posterior surface is covered with the peritoneum. In male the posterior surface is related to the seminal vesicles, ampullae of the vas and the vas deferens. Posteriorly it is related to the rectum separated from it by the fascia of Denonvillier. In female posterior surface of the urinary bladder is related to the cervix and vagina. Mucous membrane of the bladder is thrown into number of folds except over a small inverted triangular area known as the trigone of bladder. Situation of the trigone inside corresponds to the base of the urinary bladder outside. Its anterior angle presents an opening of internal urethral meatus. Its postero-lateral angles has slit like openings of the ureters. Running in between the two ureteric openings is a raised ridge along the base of the trigone. It is known as inter-ureteric ridge (Mercier’s bar). It is formed by the longitudinal muscle fibres of the ureters. If examined carefully, it will be observed that this inter-ureteric ridge on either side continues to form a fold of a mucous membrane which lies lateral to the ureteric orifice. It is known as ureteric fold and is formed by the oblique course of the ureter. Three angles of trigone are at equidistance, i.e. 2.5 cm when the bladder is empty and at 5 cm when full. Trigone of bladder has a rich blood and nerve supply. It is the most sensitive part of the bladder. Internal urethral orifice is situated at the anterior angle of the trigone and presents a

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Figure 394 Showing terminal relations of the ureter and vas near the superolateral angle of the urinary bladder

Figure 395 Showing urinary bladder seen from below

Figure 396 Showing relations of inferolateral surfaces

Figure 397 Showing inferolateral surface of the urinary bladder and relations. Note the peritoneum covers the superior surface completely and posterior partially

Figure 398 Showing interior of bladder (trigone)

Urinary Bladder

Ligaments of the Bladder:

669

cresentric outline. Behind the internal urethral orifice is the small elevation produced by the median lobe of the prostate. It is known as the uvula vesicae. Structure of the bladder : It has following coats : 1. Serous: It is partial as it covers the superior surface and upper part of the posterior surface. 2. Muscular coat (detrusor muscle): It has three layers out of which middle is circular and inner and outer are longitudinal. Some of the fibres of external layer go to the rectum. It is known as rectovesical muscle. Few fibres reach the pubis along with the puboprostatic ligaments. The fibers are known as pubovesical muscle. Middle coat is circular, well developed and surrounds the internal urethral orifice, where it forms the sphincter. The mucous membrane of the bladder is lined with transitional epithelium. There is no muscularis mucosae in the urinary bladder. Transitional epithelium is stretchable and non absorbable. It allows bladder to stretch to accommodate upto 500 cc of urine and at the same time does not allow a drop of urine to get absorbed. Several condensations of the pelvic fascia are described as true ligaments of the urinary bladder. They are as under: 1. Lateral true ligaments of the bladder: They are attached to the pelvic fascia. 2. Lateral and medial puboprostatic ligaments in male and pubovesical ligaments in female. The above ligaments form the floor of the retropubic space (cave of Retzius). Puboprostatic ligaments run from the front of the prostate to the pubis. They are lateral to the deep venous complex of the penis and are adherent to large veins, while dividing the puboprostatic ligaments, keep laterally and nearer to the pubis to avoid injury to the veins (Figure 399).

Figure 399 Showing ligaments of bladder in female

3. Median umbilical ligament: It is an obliterated urachus 4. Posterior ligaments of the bladder: They run from the bladder to the internal iliac veins.

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Blood Supply of the Bladder:

Venous Drainage:

Nerve Supply :

Somatic Nerve Supply:

Sensory Supply :

5. False ligaments of the bladder : a. Median umbilical fold. b. Medial umbilical folds. They are present over the obliterated umbilical arteries. 6. False lateral ligament of the bladder – These are the peritoneal folds which extend from the bladder to the pelvic walls. 7. Sacro-genital folds. Urinary bladder is supplied by the superior vesical artery, the branch of the obliterated umbilical artery and the inferior vesical, the branch of the anterior division of the inter-iliac artery. In addition minor contribution comes from the obturator and inferior gluteal arteries. Blood supply of the urinary bladder in female comes from the uterine and the vaginal arteries. (Please remember that there is no inferior vesical artery in female. Instead it is represented by the uterine and the vaginal arteries. In male intricate network of venous plexus is formed in relation to prostate. It is continuous with the venous plexus of the urinary bladder known as the vesical venous plexus. The venous blood from the urinary bladder drains into the internal iliac veins. Internal iliac veins are connected to the valveless vertebral system of veins. (Batson’s plexus). Being valveless blood can flow in either direction. Due to straining during defaecation and micturition there is increase pressure in pelvic veins. As a result malignant cells can reach the vertebrae and the skull. Increase in intrathoracic and the abdominal pressure results in metastasis from breast and kidney to the lung, the vertebral column and the brain. Note: Majority of the brain absesses are metastatic and are mostly from the lungs. Therefore in case of brain abcess, X-ray of the chest is mandatory. 1. Inferior hypogastric plexus is connected to the vesical plexus. Vesical plexus contains both parasympathetic and the sympathetic fibers. Parasympathetic fibers comes from sacral 2, 3, 4 and sympathetic from T11 to L2. 2. Parasympathetic fibers are motor to the wall and inhibitory to the sphincter, while the sympathetic fibers are inhibitory to the wall and motor to the sphincter. It is from the sacral 2, 3, 4 and supplies the sphincter urethrae muscle through the pudendal nerve. Somatic supply is under control of will. As long as the pyramidal tracts are intact and the bladder function remains normal. Pain fibers from the urinary bladder are carried by the sympathetic and the parasympathetic fibers. Pain occurs as a result of distension. The sensation of pain is carried by the lateral spinothalamic tract to the ventroposterolateral nucleus of the thalamus. Bilateral anterolateral cordotomy abolishes pain sensation from the urinary bladder. However the person remains aware of the distension of the bladder and the desire to micturate is unaffected. Injury to the cervical and thoracic segments of the spinal cord results in a state of “Spinal shock”. Bladder muscles are relaxed, sphincter vesicae contracts and the sphincter urethrea is relaxed. The condition leads to distension and dribbling of the urine which is followed by automatic reflex bladder. Damage to the sacral segment as a result of injury at the T12 and L1 leads to “autonomous bladder”. Flaccid bladder fills to its increased capacity, overflows which is followed by dribbling.

Urinary Bladder Lymphatic Drainage:

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Lymphatic drainage of the trigone is directed upwards and laterally through the post wall. Lymph vessels from the superior and inferolateral surfaces, go to the external iliac group of nodes. Development of urinary bladder: Urinary bladder develops from two sources: 1. Trigone is mesodermal in origin. 2. Rest of the urinary bladder is endodermal in origin, and develops from ventral part of the cloaca. Anamolies of the urinary bladder: 1. Agenesis 2. Absence of sphincter vesicae 3. Compartmental urinary bladder 4. Hour-glass urinary bladder 5. Communication with the rectum (vesico-rectal fistula). 6. Ectopia vesicae : It is due to failure of development of the infra-umbilical part of the anterior abdominal wall and the anterior wall of the urinary bladder. Possibly due to delayed rupture of the cloacal membrane. In majority of the cases the umbilicus is absent. Trigone and the ureteric orifices can be viewed from the outside. The condition is usually associated with epispadius. 7. Congenital diverticulum of the urinary bladder occurs at the junction of the trigone and the rest of the bladder.

CLINICAL

Acute Retention of Urine:

1. Cystitis : Inflammation of the urinary bladder is known as cystitis. In tubercular cystitis bladder becomes small and contracted (“Thimble bladder”). 2. Rupture of the urinary bladder. Bladder injuries are common in pelvic fractures. It is intra-peritoneal in 20% cases and extra-paritoneal in 80% cases. (Obviously due to the fact that the 80% of the urinary bladder has no peritoneal covering). Urinary bladder can rupture due to blunt and forceful blow in the hypogastric region particularly when it is full. Patient has not passed urine for some hours and is unable to do so. Urinary bladder is distended and the dullness on percussion in supra-pubic region is present. The condition is painfull. Common causes of acute retention of urine in males: 1. Urethral stone 2. Phimosis 3. Acture urethritis 4. Acute prostatitis. In females: 1. Retro-verted uterus 2. Acute urethritis. Male child: Meatal ulcer with scabbing. Note: In majority of the cases of the acute retention of the urine the correct treatment is to pass a suitable rubber catheter (tube) under all aseptic precautions. In case of failure to pass the catheter bladder is punctured suprapubically.

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Kadasne’s Textbook of Anatomy (Clinically Oriented)

Chronic Retention: Vesical Calculus:

Diverticulum of the Urinary Bladder: Herniation of Bladder:

Cystocele (Figure 384): Carcinoma of Bladder:

Cystoscopy:

As the anterior wall of the urinary bladder is in contact with the anterior abdominal wall. The peritoneum is pilled of from the anterior abdominal wall, allowing to perform the puncture cystostomy (making an opening in the bladder) without disturbing the peritoneal cavity. In fully distended bladder the internal urethral orifice is tightly closed which results in failure of passage of the catheter. After supra-pubic puncture the bladder gets emptied, the sphincter urethrae is relaxed and the catheter enters the bladder with ease. It is due to the benign prostatic enlargement and the stricture of the urethra. Stone in the bladder is known as vesical calculus. The vesical calculus can be as large as the size of the urinary bladder and is seen in plain Xray. It can be congenital and acquired. The acquired bladder diverticuli are due to increased pressure in the urinary bladder. Normally bladder pressure is 35 mm of water. It may rise to 150 cc of water, forcing the mucus membrane of the bladder between the hypertrophied muscles. Protrusion of the part of the bladder through the hernial orifice is known as herniation of the bladder. The herniation can be intra-peritoneal, paraperitoneal and the extra-peritoneal depending upon the peritoneal relations. The protrusion of the urinary through the anterior vaginal wall is known as cystocele. Carcinoma of urinary bladder is mostly transitional, however adeno carcinoma can occure in the urachal zone. It is due to the carcinogenic chemicals like benzedine and aniline dyes. An advance cases of schistosomiasis (Bilharzia) which is common in Iran, Iraque and Soudi Arebia. It is due to swimming in infected water where the nematodes penetrate the skin and enters the blood. Schistosomiasis produces ulcer in the muscosa of the urinary bladder initially and the papiloma later. Carcinoma of the urinary bladder can be diagnosed with the help of a cystoscope and removed from the base with the help of resecto-scope. Interior of the urinary bladder can be viewed by the cystoscope. Bladder is filled with fluid and the illuminated cystoscope is passed. Trigone of the bladder is seen as a pink and smooth area. Drops of urine can be seen coming through the uretric openings. Empty urinary bladder can be palpated in male by bi-manual palpation between the anterior abdominal wall and the rectum.

Prostate

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PROSTATE

Apex:

Posterior Surface (Figure 404):

Anterior Surface:

Inferolateral Surfaces: Capsula (Figure 400):

Prostate is the fibromusculoglandular organ peculiar to the male, situated at the neck of the urinary bladder infront of the rectum behind the symphysis pubis in the true pelvic cavity. Its weight is 8 gms. Its breath is more than its length. Breadth being 4 cm and length 3 cm Caecum is an other organ of the body where breadth is more than the length. Due to the passage of the urethra prostate has acquired importance. It presents base, an apex, two inferolateral surfaces-posterior surface and the small anterior surface. Base is in contact with the neck of the urinary bladder. It is pierced by the urethra which comes out from the anteiror surface a little infront of the apex (see Figure 385). Apex of the prostate is directed downwards and is related to the sphincter urethra and deep transverse perinei muscles. Urethra comes out of the prostate the anterior surface of the prostate. Urethra is placed more anteriorly than posteriorly in the prostate. It look cresentic in a transvers section. The posterior surface is related to the rectum separated by fascia of Denonvillier. Ejaculatory ducts enter the posterior surface of the prostate through a small depression. The portion of the posterior surface above the depression is the median lobe. Median lobe of prostate lies in between the ejaculatory ducts and prostatic part of urethra. Posterior surface of the prostate below the entry of the ejaculatory duct presents the medial sulcus. Obliteration of the median sulcus felt on rectal examination is suggestive of cancer of the prostate. The right and left lobes are continuous with each other in front. It is known as the anterior lobe of the prostate. It is mainly fibrous. Anterior surface is narrow and convex. It is connected to the body of pubis through the the puboprostatic ligaments. Urethra comes out of the prostate through the anterior surface, infront of the apex. They are related to the levator ani muscles laterally. The part of it related to the prostate are known as levator prostate. Prostate has two capsules, 1. The fibrous 2. Fascial.

Figure 400 Showing horizontal section of prostate (diagrammatic)

Fibrous to capsular lies inside the facial capsule. It is formed by the fibrous tissue of the prostate. The fascial capsule is formed by the visceral layer of the pelvic fascia. It is important to remember that the prostatic venous plexus lies between the fibrous and the fascial capsules. Prostatic part of urethra and the ejaculatory ducts pass through the prostate. Prostatic utricle lies on the posterior wall of the prostatic part of the urethra. Ejaculatory ducts

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Kadasne’s Textbook of Anatomy (Clinically Oriented) run obliquely downwards and forwards to open into the prostatic part of urethra over the verumontanum on either side of the opening of the prostatic utricle.

Prostatic Part of Urethra (Figure 403):

Prostatic Utricle (Figure 401): Blood Supply:

Venous Drainage (Figure 402):

Figure 401 Showing sagittal section through prostatic part of urethra in front and ejaculatory duct behind forming limit of median lobe of prostate

Figure 402 Showing horizontal section of prostate

Note: In the event of long standing prostatic adenoma the peripheral portion of the prostatic tissue forms the third capsule of the prostate due to compression. Prostatic part of urethra is 3 cm in length although it has been described as having a vertical course. The prostatic part of urethra takes the slightly curved course. It is like a barrel, wider in the middle, narrow above and narrow below. In the cross section it presents cresentic appearance, due to the urethral crest which projects from its posterior wall. Shallow depressions lying on either side of the prostatic crest are known as prostatic sinuses where it receive openings of the prostatic ducts. Elevation in the middle of the urethral crest is known as veru monatanum where ejaculatory ducts and the posterior utricle open. The prostatic utricle is a blind sac lying in the substance of the prostate. It is homologus to the uterus in female. It opens in the prostatic part of urethra at the colliculs seminalis (verumontanum) between the openings of the ejaculatory ducts, it develops from the para mesonephric ducts. Blood supply of the prostate mainly comes from the inferior vesical artery branch of the anterior division of the interior iliac artery. Prostate is supplied by the following arteries. 1. Inferior vesical 2. Internal pudendal 3. Middle rectal. An intricate venous plexus is formed surrounding the prostate between the fibrous and the fascial capsule. It receives the deep dorsal vein of penis and drains into the internal iliac veins. Prostatic venous plexus also communicates with vertebral venous plexus which are valveless (Batson’s plexus) permitting cancer cells of prostate to travel to pelvic bones and vertebral column and may be even to the cranium.

Prostate

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Figure 403 Showing inferior prostatic part of urethra

Figure 404 Posterior surface of urinary bladder

Lymphatic Drainage: Histology:

Clinical:

Investigation:

Lymph vessels from the prostate drain into the internal iliac, sacral and the external iliac lymph nodes. It is fibro-musculo-glandular organ. Glandular tissue presents number of follicles which are lined with columnar epithelium. Ducts are lined with the cubical cells. Amyloid bodies are found in the lumen of ducts. Two zones of the prostate are described histologically. In the outer zone are long and branched glands. Ducts of these glands curve backwards and open into the floor of the prostatic sinus. The inner zone presents the submucosal and mucosal glands. Outer zone is prone for the malignant growths and the inner for the benign. 1. Per-rectal examination of the prostate is done with a gloved finger in the left lateral position. Prostate is palpated for the evidence of enlargement, nodule, abscess and the carcinoma. Obliteration of the median sulcus on the posterior surface of the prostate is suggestive of the carcinoma. Adherent rectal mucosa to the posterior surface of the prostate is the certain sign of local spread of the cancer with raised serum acidphosphatase. 2. Carcinoma prostate: Clinically are the early symptoms prostatic enlargement, which appears most insignificant. Ultrasonography shows mild prostatic hypertrophy with raised PSA (prostrate specific antigen). Prostatic secondaries in the spine are osteoplastic and reach the spine through vertebral venous plexus. For carcinoma of prostate i. Clinical examination—per-rectal examination ii. Acid phosphatase iii. Prostate specific antigen iv. X-ray of spine v. Ultrasound of abdomen and pelvis. 3. Benign prostatic enlargement of the prostate is common in male after the age of 50 years. It is the median lobe of the prostate which enlarges and passes through the internal sphincter (Spincter vesicae). As a result the urine enters the prostatic part of the urethra leading to the

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Kadasne’s Textbook of Anatomy (Clinically Oriented) intense desire for micturation. (Urgency). Due to the enlargement of the median and the lateral lobes of the prostate, the urethra gets elonaged, compressed and deform. Patients complains of difficulty in passing urine (Dysurea). Patient is able to pass urine only when he relaxes. Forced urination helps in passing the urine in case of the stricture urethra. Due to the enlargement of uvulae vesicae the pouch is formed behind the uvula resulting in the increased quantity of the residual urine. Urine collects, stagnets and gets infected causing cystitis. Enlarged prostate presses on the prostatic venous plexus which is connected with the vesical venous plexus. Vesical veins dilate, rupture and bleed leading to haematuria and is known as vesical or the prostatic piles. During prostactomy the prostatic adenoma is removed leaving the three capsules untouched including the venous plexus particularly when the 3rd capsule is well formed. Damage to the fibrous capsule leads to haemorrhage as the prostatic venous plexus lies between the true and the false capsules. As the prostatic bridge infront of the urethra does not contain glandular tissue. It is immune from prostatic hypertrophy and is never involved in benign prostatic enlargement. Fascia of Denonvilliers intervenes between the prostate infront and the rectum behind. In carcinoma of the rectum, the rectum is separated from the prostate and the urethra through the plane of the fascia of Denonvilliers, which is rarely penetrated in the prostatic malignancy.

Development:

Age Changes in Prostate:

Female Homologues of prostate:

Surgical approaches for removal of prostate: 1. Suprapubic 2. Retropubic 3. Transperineal – Plane is through the fascia of Denonvillier infront of the rectum. The plane does not exist in malignant conditions. 4. Transurethral - TUR (Trans Urethral Resection) - It is done with the operating cystoscope. Endoscopic removal of the enlarged prostatic tissue is the preferred procedure in these days. In trans-urethral resection of the prostatic tissue surgeon has to be proximal to the veru montanum in order to prevent the damage to the urethral sphincter. Hence, veru montanum is an important landmark for the operating surgeon. Prostate develops in the form of five buds which arise from the epithelium of the prostatic part of the urethra (i.e. Caudal part of vesico urethral canal) and also from the pelvic part of definitive urinogenital sinus. The buds give rise to secretary epithelium of the prostate. The buds arising from the mesodermal part of the prostatic part of the urethra form the inner glandular zone of the prostate. Buds arising from the remaining part of the prostatic part of urethra are endodermal and form the outer glandular zone of prostate. Outer zone of the prostate develops earlier than the inner and is the zone of malignancy. The inner zone which develops later is for the benign prostatic hypertrophy of the old. Connective tissue and the muscles are derived from the surrounding mesoderm. Secretary structures of the prostate are rudimentary at birth. They get well developed at the time of puberty. In old age it undergoes progressive atrophy. However in some it undergoes benign hypertrophy, possibly due to the hormonal effects. The buds arising from the urogenital sinus give rise to paraurethral glands of Skene.

Vas Deferens

677

VAS DEFERENS Introduction:

Situation (Figures 405 and 406):

Course of the Vas (see Figure 393):

Figure 405 Showing cross section of spermatic cord and its components with coverings

Figure 406 Showing pelvic courses of ureter and vas in male

It is the thick muscular tube having lumen ment for the passage of spermatozoa from the epididymis to the prostatic part of the urethra through the ejaculatory ducts. On palpation it feels hard like a cord. It is dialated before joining the duct of the seminal vesical which is known as the ampulla. It is 45 cm in length. The vas deferens lies in the scrotum along the posterior border of the testis, medial to the body of epididymis. It enters the superficial inguinal ring forming the part of the spermatic cord. It crosses the greater and the lesser pelvises while crossing the external iliac artery. It crosses the inferior epigastric artery at an acute angle and finally reaches the supero-lateral angle of the urinary bladder where it crosses the ureter from the front and joins the duct of seminal vesical to form the ejaculatory duct at the base of the bladder. It begins as the continuation of the tail of epididymis runs along the posterior border of the testis lying medial to the body of epididymis. It joins the spermatic cord at the upper pole of the testis. In the spermatic cord it is covered by the external, cremastric and the internal spermatic fascias along with other structures like testicular artery, artery of the vas, pampiniform plexus, lymphatics and the nerves. It enters the superficial inguinal ring, travels through the inguinal canal and comes out through the deep ring leaving the company of the spermatic cord. It crosses the external iliac artery and hooks round the inferior epigastric artery. It runs downwards, backwards and medially running on the lateral pelvic wall.

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Blood Supply :

Venous Drainage: Histology :

Development :

During its course on the lateral pelvic wall it crosses the obliterated umbilical artery, the obturator nerve, vessels and the inferior vesical vessels. It reaches the superolateral angle of the bladder where it crosses the ureter from the front and goes to the base of the urinary bladder. It lies on the medial to the seminal vesical and presents dilatation known as ampula of the vas. It joins the duct of the seminal vesical and forms the ejaculatory duct which passes through the prostate and opens into the prostatic part of the urethra over the calliculus seminalis (Verumontanum). It is supplied by the branch of the superior vesical artery and sometimes of the branch of the inferior vesical artery. As the artery of the vas accompanies the vas to the testis, it anastomoses with the testicular artery. Veins of the vas drain into the vesical venous plexus and finally into the internal iliac vein. It is the thick muscular tube having a small lumen. Muscle coat of the vas has three layers. Outer longitudinal, inner longitudinal and the middle circular. Its outer coat is formed by thin layer of the connective tissue having nerves and arterioles. Vas deferens develops from the mesonephric duct.

CLINICAL Vasectomy: Vasectomy is widely practiced as the means of method of sterilization of the male in the National Family Planning Programme. Bilateral vasectomy is done under local anesthesia. The vas is fixed between the fingers, a small transverse incision is made and the vas is lifted with the tips of the small artery forceps. Loop of the vas is held up. It is ligated with thread at two places and the intervening part is cut. Cutting of the long segment of the vas is avoided as reunion of the vas may pose a problem when required. Vasectomy has no deleterious effects on the body. Testicular hormones continue to enter the body through blood. In due course of time all the spermatozoa get reduced in number and get phagocytosed. It is scientific to advise the use of condom during the immediate post-vasectomy period.

Seminal Vesicles

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SEMINAL VESICLES

Blood Supply (Figure 407):

They are two coiled sacculated tubes situated between the urinary bladder infront and the rectum behind. Each has the length of 5 cm. It is pyramidal in shape and its upper end is directed upwards and laterally. The upper end is related to the the ureter and the vas deferens near the supero-lateral angle of the bladder. Lower down its duct units with the vas to form the ejaculatory duct. If uncoiled it measures about 15 cm in length and has a diameter of 3 to 4 mm. Ampula of the vas is medial to the seminal vesical. As the name indicates it is the store house of the semen. Seminal vesicle is supplied by the branches of the inferior vesicle and middle rectal arteries.

Figure 407 Showing sagittal section of testis

Nerve Supply: Function: Histology:

Development: Clinical :

Diverticulum of the Seminal Vesicle:

Seminal vesicles receive their nerve supply from the 1st lumbar sympathetic ganglion through sacral plexus. Seminal vesicle is the store house of semen. It adds seminal fluid which contains fructose and enzyme vesiculase. It has an alkaline pH. It presents three coats: 1. Outer, 2. Middle, and 3. Inner. Outer coat consists of areolar tissue, middle muscular and the inner is mucous. Mucous layer presents columnar epithelium. Diverticuli from the seminal vesicles are lined with goblet cells. Secretion of the goblet cells is the main bulk of the seminal fluid. Seminal vesicles are mesodermal in origin and arise from mesonephric ducts. 1. Seminal vesicle can be palpated per-rectally. They enlarged in tubercular infection. 2. High lumbar sympathectomy done on both sides results in loss of ejaculation and sterility. 3. Laterally, it is related to the prostatic venous plexus. When it is present the kidney of that side is absent. Diverticulum of seminal vesical represents an abortive attempt for the formation of the ureteric bud.

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FEMALE GENITAL ORGANS UTERUS Introduction:

Position of the Uterus (Figure 408):

Measurements: Weight : Parts of the Uterus:

Uterus is known as the womb. It is also known as hystera from which the word hysterectomy, hysteretomy and hysteroscopy are derived. It is the child bearing organ of the female placed in the true pelvic cavity between the urinary bladder in front and the rectum behind. It is pyriform in shape, thick walled and firm. Uterus is anteverted and anteflexed. When the long axis of the uterus makes an angle with the long axis of the vagina is known as antiversion. When the long axis of the uterus makes an angle with long axis of the cervix it is known as antiflexion. The angle of antiversion is 90° while the angle of antiflexion is 125°. Both the angles are open anteriorly. The long axis of the uterus corresponds with the axis of the pelvic inlet and the long axis of the vagina corresponds to axis of the pelvic outlet. In nullipara the dimensions of the uterus are 2.5 cm in thickness, 5 cm in breadth and 7.5 cm in length. In nullipara its weight is 30 gm. Uterus has the body, fundus, cervix and the uterine tubes. Normally body of the uterus is 2/3 and cervix is 1/3rd. In infantile uterus this proportion is reversed.

Figure 408 Normal position of uterus

Body of the Uterus:

Uterine tubes open in the upper part of the body of the uterus through the uterine ostia. The part of the body of the uterus above the openings of the uterine tubes is known as the fundus. Lower one-third of the uterus is cylindrical and is marked from the body by a small constriction out-side. Internal os an opening connecting the uterine cavity and the cavity of the cervix lies at the level of constriction. Lower end of the cervix opens into the vagina through its anterior wall. The cervix presents two parts the supravaginal and the intravaginal. Lower end of the cervics opens into the vagina through the external os. Intravaginal part of the cervix is surrounded by vaginal fornices of which the posterior fornix is the deepest, where the semen is deposited ofter coitus. In case of rape, vaginal swab is taken from posterior vaginal fornix for the evidence of semen in medicolegal cases (Figures 409, 409A and 410). Fundus of the uterus is convex like a dome and looks anteriorly when the urinary bladder is empty. It presents two corners which receive the uterine tubes. Body of the uterus presents anterior and posterior surfaces, two lateral borders in addition to the fundus.

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Figure 409 Showing parts of the uterus and broad ligament

Figure 409A Showing crossing of ureter by uterine artery close to lateral vaginal fornix. Note circular, anterior azygos, posterior azygos and lateral cervical arteries

Figure 410 Showing female pelvic organs with peritoneal reflection

Relations of the Anterior Surface: Relations of the Posterior Surface:

Uterine Cavity:

The anterior surface of the body of the uterus is covered with the peritoneum only up to the level of the internal os. Anterior surface of the uterus is related to the superior surface of the urinary bladder and the peritoneal pouch known as uterovesical pouch. Posterior surface is covered with the peritoneum and forms the anterior wall of the of rectouterine pouch. The pouch is occupied by the coils of the intestine and the sigmoid colon. As an abnormality an overy can be seen hanging in the rectouterine pouch. Near the opening of the uterine tube is the attachment of round ligament of the uterus antero-inferiorly and the attachment of the ligament of ovary, postero-inferiorly. The lateral borders of the uterus give attachments to the broad ligaments and are related to the wavy course of the uterine arteries. In sagittal section it is like a slit while in the coronal section it looks like an upright triangle with the base directed upwards and the apex downwards. The uterine cavity opens into the cavity of the cervix through the internal os.

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Site of Implantation of the Fertilized Ovum: Cervix (Figures 411 and 412):

Fertilised ovum enters the uterine cavity through the uterine ostium of the tube and gets implanted on the posterior wall of the uterus near the fundus. After implantation of the ovum, the changed character of the endometrium is known as a ‘decidua’. Cervix forms the lower 1/3rd of the uterus with which it makes an angle of 125°. It is like a barrel, i.e. broad in the middle, narrow above and below. It has a length of 2.5 cm and has two parts, i.e. supravaginal and the intravaginal. Intravaginal part opens in the vagina through its anterior wall. It is surrounded by the fornices of which the posterior one is the deepest. External os is round and firm in nullipara. It presents anterior and the posterior lips, the posterior being larger. Os and the lips lie in direct contact with the posterior vaginal wall in multipara. External os has the mucous covering of non-keratinising stratified squamous epithelium. Hence, the carcinoma of the cervix is of the squamous cell variety.

Figure 411 Interior of cervix with external os and internal os. Note palmate folds

Figure 412 Female genital organs

Supravaginal Portion of Cervix:

Interior of the Cervix:

Anteriorly it is related to the urinary bladder, posteriorly to the coils of intestine in the rectouterine pouch, sigmoid and the rectum. Laterally it is related to the thick parametrial tissue which harbours ureter and the uterine artery. Gartner’s duct may be related to the supravaginal portion laterally. Gartner’s duct is the caudal part of the duct of the epoophoron which may persist up to the hymen. Anterior and posterior walls of the cervix present vertical ridges from which number of oblique folds arise. They are known as palmate folds. The appearance of the wall of the cervix is known as orbor vitae uteri. Folds of the anterior and posterior walls interlock and close the cervical canal. Lower two thirds of the cervical mucosa shows menstrual changes.

Female Genital Organs Communication:

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Uterine cavity has a communication lower down with the vagina and above with the peritoneal cavity through the uterine tubes, fimbria and their ostia which promotes pelvic infections in females. The difference between the male and the female peritoneal cavities lies in the fact that the female peritoneal cavity is not the closed cavity and has an access to the exterior, while the male peritoneal cavity is totally closed. This explains the higher incidence of pelvic infections in the female. Structure of the uterus: It presents three coats: 1. Serous, 2. Muscular, and 3. Mucous (Endometrium): It undergoes cyclical changes every month. Muscular coat is also known as myometrium which is thick in the middle of the body and thin at the fundus. It is thin where the uterine tubes join the uterine cavity. Muscular coat is arranged in three layers. The outer and inner longitudinal muscle coat continues with the uterine tubes and all the ligaments. Middle coat is thick and has longitudinal, oblique and transverse fibers around large blood vessels which act like living ligatures during uterine haemorrhage. Mucous membrane is lined with the ciliated columnar epithelium before puberty and gets non-ciliated in adults. It contains blood vessels and tubular uterine glands. Ligaments of the uterus: Ligaments of the uterus are the primary supports of the organ. Ligaments: They are divided into the true and the false. True ligaments (Figure 413): True ligaments are made of fibromuscular bands. False ligament : They are simply folds of peritoneum. They are as under:s 1. Anterior ligament: It is the fold of peritoneum running from the uterus to the urinary bladder. It covers the uterus only up to the level of internal os.

Figure 413 Showing ligaments of uterus

Broad Ligament (Figure 409):

2. Posterior ligament (Figure 412): It is the fold of peritoneum running from the back of the posterior fornix to the rectum. 3. Uterosacral ligament (Figure 415): They are the folds of the peritoneum running from the cervix to the front of the sacrum on either side of the rectum. They keep the uterus in position by pulling it towards the sacrum. It is the double fold of peritoneum which extends from the lateral border of the uterus to the lateral pelvic wall from medial to lateral side. Vertically, it extends from the uterine tube to the pelvic floor. Uterine tube lies in its free margin occupying the medial four fifth. The broad ligament between

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Figure 414 Showing uterus with tubes and ovaries, ligaments and epoophoron and paroophoron. Note the Gartner’s duct by the side of vagina and crossing of ureter by uterine artery near lateral vaginal fornix

Figure 415 Showing pelvic part of ureter in female

the lateral end of tube and the pelvic wall is known as infundibulopelvic ligament. Ovary is enclosed in the posterior layer of the broad ligament. The part of the broad ligament which attaches the ovary to the its posterior layer is known as meso-ovarium. Part of the broad ligament near the tube is known as meso-salphinx. Ligament of the ovary, round ligament of uterus, ovarian and, uterine vessels, epoophoron and the paroophoron are the contents of broad ligament. Ureter lies at the lower border of the broad ligament where it is crossed by the uterine artery from above near the lateral vaginal fornix.

TRUE LIGAMENTS Round Ligament (Figure 413 and 416A):

Clinical: Ligament Ovary:

The round ligament is 10 cm long and is attached to the uterus just below and in front of the attachment of the uterine tube. It runs along the lateral pelvic wall crossing the structure there, enters the deep inguinal ring and enter the inguinal canal. It comes out of the inguinal canal through the superficial inguinal ring and gets attached to the skin of the labium majus. Lymphatic from the portion of the uterus near the attachment of the tube run along the round ligament and go to the superficial inguinal group of lymph nodes. Cancer of the fundus of the uterus may spread to the superficial group of lymph nodes. The round ligament of the uterus is the remnant of the gubernaculum. It helps in maintaining the anteverted and the anteflexed positions of the uterus. In retroverted uterus the round ligament of uterus is shorten by plication. The ligament of ovary attaches the uterine pole of the ovary to the fundus of the uterus below and behind the attachment of uterine tube. It is the remnant of the proximal part of the gubernaculum.

Female Genital Organs Lateral Cervical Ligament (Mackenrodt’s Ligament) :

Supports of Uterus (Figure 416B):

Figure 416A Normal axis of the uterus is parallel to the axis of floor of pelvis

Figure 416B Showing true ligaments of cervix

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They are the strong fan-shaped ligaments, formed by the condensations of the endo-pelvic fascia. They act like a hammock (meaning of the word hammock is hanger bed of canvas or rope mesh. Medially, it is attached to the cervix and the adjoining part of the vagina and runs along the pelvic floor in company with the blood vessels. It is considered as one of the important factors in preventing the prolapse of the uterus. It gets laxed and elongated in prolapse of the uterus. Apart from these factors there are other factors which should be mentioned: 1. Pelvic diaphragm formed by levator ani muscle 2. Urogenital diphragm : Formed by the muscles of the deep perineal pouch, i.e. sphincter urethrae and the deep transverse perini muscles with covering dorsal ventral parts of the sphincter urethral muscle. 3. Perineal body 4. True ligaments, i.e. pubocervical, lateral cervical and utero-sacral. 5. Surrounding organs. 6. Intra-abdominal pressure Uterus undergoes changes in size and the position during pregnancy. As the result of hormones in pregnancy all the pelvic ligaments get laxed and lengthened. The six ligaments two pubocervical, two lateral cervical and two utero-sacral form the anchoring cross at the pelvic floor for the lower part of the uterus, i.e. cervix. It has a stabilizing effect on the lower part of the uterus which resists sagging down of the cervix through the vagina preventing prolapse of the uterus. The role of the pubo-cervical ligament is to pull the cervix anteriorly, role of the uterosacral ligament is to pull the cervix posteriorly while the lateral cervical ligament prevents its side to side displacement in the transverse axis and also act as the hammock. The natural tendency of the uterus anteverted and antiflexed, which is maintained or even accentuated by the tie rope like forward pull of the round ligament. In Fother-gill’s operation elongated supravaginal part of the cervix is removed (amputed), and the ligaments are tightened.

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Figure 417 Showing lymphatic drainage of uterus

Blood Supply of the Uterus (Figures 414 and 415):

Venous Drainage of the Uterus: Nerve Supply of the Uterus:

Age Changes in Uterus:

Uterus is mainly supplied by the uterine artery which is the branch of the anterior division of the internal iliac artery. It runs towards the cervix crosses the ureter above, 2.5 cm lateral to the cervix and enters the broad ligament. In the broad ligament it follows the lateral border of the uterus and turns laterally at the junction of the body of the uterus and the uterine tube to anastomose with the ovarian artery. Vertical course of the uterine artery is wavy which permits its expansion during pregnancy when the uterus becomes an abdominal organ. Uterine artery supplies the cervix, medial 2/3rd of the uterine tube, ovary, ureter and the vagina. Branches of the uterine artery lower down anastomose with the branches of the vaginal artery and form two trunks, infront and behind the vagina. They are known as azygos arteries of the vagina. Branches given to the uterus are known as vasa recti. Uterine artery gives circular, later cervical and azygos arteries of vagina. It drains into the uterine, ovarian and the vaginal veins, finally reaching the internal iliac veins. Near the meso-ovarian is the pampiniform plexus of veins. They can go varicose. Uterus is supplied by both the sympathetic and the parasympathetic nerves. It comes from the hypogastric and the ovarian plexuses. Sympathetic nerve supply comes from T12 to L1 segment of the spinal cord. Stimulation of the sympathetic promotes the contraction of the uterine muscles in addition to vaso-constriction of the arteries. Sacral 2, 3, 4 segments give parasympathetic nerve supply to the uterus. Stimulation of the parasympathetic nerve relaxes uterine muscles and causes vasodilatation. Sensation of pain from the body of the uterus run along the sympathetic nerves and the pain fibers from the cervix follow the parasympathetic nerves. For painless labour caudal block is given to block the pain fibers carrying to the S2, S3 and S4 segments. In infuntile uterus proportion of the cervix to the body is 2/3rd and 1/3rd. At the age of fourteen, the size of the uterus increases and it occupies the adult position with the appearance of the arbor-vitae uteri in the interior of the cervix. The size of the uterus enlarges in pregnancy due to hypertrophy of the muscle fibers and also due to the hyperplasia. After delivery uterus undergoes involution and returns to its non-pregnant status. Uterus atrophies and gets reduced in size in old age. The openings and the lips of the uterus are hardly visible.

Female Genital Organs Structure of Uterus:

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It has partial peritoneal covering. Main bulk of the wall of the uterus is formed by smooth thick muscle layer known as myometrium. Muscle fibres are cris-cross and spirally arranged surrounding the blood vessels which act as living ligature. There is no submucosa. Endometrium consists columnar cell, ciliated before menstruation. Uterine glands are simple unbranched coiled and long.

CLINICAL Prolapse of Uterus:

Axis of Uterus:

Copper T and Loop: Hysterosalphingography: Hysterectomy:

Caesarean Section:

Carcinoma of the Cervix:

D and C:

Passing of the uterus downwards into the vagina is known as uterine prolapse. It is the result of failure of various factors which form the uterine supports. Repeated pregnancies and trauma to the pelvic diaphragm (levator ani) are the main factors for the prolapse of the uterus. Tearing of the perineal body if not repaired properly, pre-desposes to the uterine prolapse. The axis of the body of the uterus runs along the axis of the inlet of the pelvis and the axis of vagina runs in line with the axis of the outlet. The position of the uterus, i.e. anteverted and antiflexed itself are the factor which resists prolapse of uterus. Insertion of copper T and a loop (Lipp’s) is being practiced as the methods of the family planning. Presence of foreign body in the uterine cavity does not allow implantation of the fertilised ovum. Visualisation of the interior of the uterus and its tube is done with the help of radiopaque material. It is known as hysterosalphingography. Hysterectomy means removal of uterus. It is of three types total, subtotal and pan-hysterectomy. Subtotal hysterectomy is hardly done, these days, while the pan-hysterectomy is done for the malignant conditions. Hysterectomy can be done through abdominal and the vaginal routes. During hysterectomy injury to the ureter is the most feared complication. If detect during operation it should be repaired. Detection of ureteric injury can be diagnosed by intravenous pyelography (IVP). Caesarean is more popular in these days than giving trial during the labour. Before surgery urinary bladder is emptied by passing a catheter. Abdomen is opened and the bladder is pushed down from the uterus which carries the peritoneum off the uterus. Transverse incision is given over the lower surface of the uterus and the incision is widened with fingers. To prevent bleeding from the cut edges of the uterine incision the angles of the incision are caught in the spong holding forceps and pulled up. The baby is delivered which is followed by extraction of the placenta with the membranes and the wound is closed in two layers. Begnine tumours of the body of the uterus are mostly fibroids. Carcinoma is more common than the carcinoma of the body of the uterus. As the lining of the external os of the cervix is covered with nonkeratinising stratified squamous epithelium the malignancy of the cervix is the squamous cell carcinoma. It spreads rapidly due to its reach lymphatic connections. D and C is the dilation and the curettage operation done for the endometrial pathology such as dysfunctional uterine bleeding and determination of ovulation. D and C is done for abortion under the MTP Act in the government approved clinics (MTP – Medical termination of pregnancy).

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Fibroids:

In fact they are leomyomas with good amount fibrous tissue. The can be small, large, single or multiple. Subserous fibroids grow in the broad ligament. Cervical fibroids are extraperitoneal and get fixed to the pelvis. They press on the bladder and dis places ureters. Fibroids in broad ligament at times cause polycythemia and hypoglycaemia. Both disappear after removal of tumour.

Vagina

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VAGINA

Clinical:

Figure 418 Showing vagina and bulb of vestibule, hymen and paraurethral gland

Vagina means sheath (Kolpos). It a fibromuscular canal lined by stratified squamous epithelium (non-keratinised). It is a female copulatory organ and yet devoid of glands. Pre-coital lubrication of the vagina is from the mucus secretion of the cervical glands. It can be said that the cervix is an oil-can of the vagina. It extends from the cleft between labia minora to the cervix. It lies behind the urinary bladder and in front of the rectum. Its anterior wall is shorter than the posterior. Anterior wall being 8 cm and the posterior 10 cm, interior of the vagina has longitudinal double column ridge running on the anterior and posterior walls running circumferentially from the columns are the folds. They are known as rugae. Vagina is able to distend during labour due to these rugae. Hymen: It is a delicate thin elastic membrane guarding vaginal entrance half hearted, as it has aperture or apertures obviously for the exit of menstrual blood, hymen is relatively avascular hence rupture causes little bleeding. 1. Epithelial cell of vaginal wall contain glycogen which is freed due breakdown of cells. Doderlins bacillus is normal resident of the vagina. Glycogen liberated by the cells is acted upon by Doderlin bacillus results in product lactic acid. Vaginal acidity given power of resistance to vagina against pyogenic organism (Acidity is a boon). 2. Non-rupture of hymen is not the proof or virginity. Coitus can be performed without rupture of hymen. It is the resistance of the edge of hymen felt with a finger. 3. Vesico-vaginal fistula–It has most destressing symptom, e.g. leaking of urine, soiling of clothes and offensive odour. Woman becomes a self and social dislike. Repair VVF (vesico-vaginal fistula should be done by an experienced surgeon better by a uro-surgeon. Cervix opens into the upper part of its anterior wall. Small pockets surround the intravaginal portion of cervix. They are known as fornices (i.e. anterior, posterior and two lateral). Posterior fornix is the deepest where the semen is deposited. Urethra is embedded in the anterior vaginal wall (Figure 418).

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Blood Supply of the Uterus and the Cervix: Blood Supply of Vagina:

Nerve Supply of the Uterus and Cervix: Nerve Supply of Vagina:

Lymphatic Drainage of the Vagina: Development of Vagina: Development of Uterus:

Posterior wall of the upper part of the vagina is covered with peritoneum. Peritoneum leaves the middle third of the santerior surface of the rectum and covers the upper part of the posterior wall of the vagina. In between the uterus infront and the rectum behind it forms the recto-uterine pouch. It is also known as pouch of Douglas. Lower part of the posterior wall of the vagina is related to the perineal body. Its middle part is related to the rectum behind separated by the fascia of Denonvilliers. Ureters are related to the lateral fornices of the vagina and during their further course they actually lie in front of the vagina. Two centimeters lateral to the lateral fornices the ureters are crossed by the uterine arteries from above at the lower border of the borad ligament. The left ureter is closer to the left lateral vaginal fornix, as the uterus has the tendency to tilt to the right. Uterus is supplied by the uterine and ovarian arteries. Uterine artery is a branch of internal iliac. Ovarian artery is the branch of the abdominal aorta. Uterine artery is known for its tortuous course. Both anastomose in the broad ligament. Veins drain into the internal iliac veins. It is supplied by vaginal, uterine, internal pudendal and middle rectal arteries. Veins go to the internal iliac vein. Branches of the uterine artery lower down anastomose with the branches of the vaginal artery and form two trunks, infront and behind the vagina. They are known as azygos trunks. Nerves come from the hypogastric and ovarian plexuses and also from the pelvic splanchnic nerves. Pain fibres mainly travel along the pelvic splanchnic nerves. It is innervated by the vaginal plexuses and the pelvic splanchnic nerves. Lymphatic drainage of uterus and the cervix: Lymph vessels are arranged into two sets: 1. Superficial, and 2. Deep. Lymph vessels from the cervix go to the internal iliac, external iliac and the sacral group. Lymph vessels from the upper part of the body of the uterus go to the aortic group along with the lymph vessels of the uterine tube. Lymph vessels from the lower part of the uterus go to the external iliac group. Lymph vessels from the area of the uterus near the attachment of the uterine tube drain into the superficial inguinal group along the round ligament of uterus. Cancer of the uterus may spread along this route and the superficial inguinal nodes may get involved. Portion of vagina below the hymen drains into the superficial inguinal lymph nodes. Lymph vessels from the rest of the vagina go to the external iliac group of lymph nodes. Vagina is formed by canalization of the vaginal plate. Its mucosa is endodermal in origin. It is mesodermal in origin and develops from fused part of the paramesonephric ducts. Mucosa of the uterus is mesodermal in origin Note: Different source of origin of mucosa of vagina and uterus makes the oestrogens to act differently on them. Congenital anomalies of uterus : 1. Absence of uterus 2. Uterus having septum (septate uterus) 3. Unicornuate uterus 4. Bicornuate uterus 5. Infantile uterus.

Uterine Tubes

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UTERINE TUBES

Function of the Uterine Tube:

Ampulla:

Isthmus:

Structure of the Tube: Blood Supply: Lymphatic Drainage: Development of Uterine Tubes:

Clinical :

Uterine tube is 10 cm long. It is enclosed in the free margin of the broad ligament. It opens into the peritoneal cavity laterally through the fimbrial ostia and into the uterine cavity medially through the uterine osteum. Uterine osteum is 1 mm in diameter. It presents four parts as under from lateral to the medial side. 1. Infundibulum, 2. Ampulla, 3. Isthmus, and 4. Intramural part, fibriae arise from the infundibulum and open into the peritoneal cavity. One of the fimbria is larger and lies in contact with ovary. It is known as ovarian fibria. It provides the site for the fertilization of the ovum in its ampullary part of the uterine tube. It nourishes the fertilized ovum which is carried for implantation to the uterine cavity. Similarly, it provides the path for the spermatozoa to reach the ovum. It is placed medial to the infundibulum. It forms lateral 2/3rd of the uterine tube. It is dialated and forms an arch over the upper pole of the ovary. Its length is about 6 to 7 cm and has a diameter of 4 mm. It lies medial to the ampulla, its length being 2 to 3 cm. Intramural part of the uterine tube lies in the uterine wall and has a length of 1 cm It opens at the superolateral angle of the uterine cavity. Course of the infundibulum and the ampulla is horizontal, it runs in the posterolateral direction. Ampulla is related to the anterior and the posterior borders of the ovary. It arches over the upper pole of the ovary. Ampulla is in contact with the medial surface of the ovary. Fertilisation of the ovum occurs in ampullary part of the uterine tube and it travels to the uterine cavity for implantation on the posterior wall near the fundus. The journey of the fertilized ovum from ampula to the uterine cavity is due to 1. Muscular contractions of tubal muscles, 2. Cilia, 3. Flow of fluid which is directed towards the uterine cavity, and 4. Negative pressure in the uterine cavity. It presents a serous coat, subserous coat, muscular coat, submucous coat and the mucous coat. Mucous coat is thrown into number of folds and is lined by ciliated columnar epithelium. By the ovarian and the uterine arteries. It goes to the aortic group of nodes along with the vessels from the ovary and the fundus of the uterus. Uterine tubes are mesodermal in origin and develop from para mesonephric ducts lying cranial to the utero-vaginal canal. Anomalies of uterine tubes: 1. Absence of tube on one or both sides, 2. Double tube, 3. Congenital narrowing or atresia. Inflammation of the uterine tube is known as salpingitis. Infection travels from the vulva and vagina through the uterus to the uterine tube. The tube gets filled with pus which trickles in the peritoneal cavity and causes

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Ectopic Pregnancy and Rupture:

pelvic peritonitis. Pelvic petitonitis leads to collection of pus in the pouch of Douglas and forms the pelvic abscess. Implantation of fertilized ovum in the tube is known as tubal pregnancy. Around during 3-4 months of pregnancy the tube cannot hold the products of conception due to the absence of desidua and eroding action of the trophoblast the tubal wall gets destroyed and leads to tubal ruptures. Blood pours in the pouch of Douglas. Blood reaches the upper part of the abdomen, giving rise to pain, tenderness and guarding of anterior abdominal wall. Irritation of the diaphragmatic peritoneum gives referred pain at the shoulder. Intra-peritoneal hemorrhage can be fatal in the ruptured ectopic. It can be confirmed by calpo puncture which shows presence of blood in the pelvic cavity (Pouch of Douglas).

FAMILY PLANNING Tubectomy:

Hysterosalphingography: Hysteroscopy: Laparoscopic Tubectomy:

Tubectomy is the standard method of family planning in which the uterine tubes are ligated at two places and the interveining portion of the tube is resected. This is known as tubectomy or tubal ligation. Care is taken not to excise a long segment of uterine tube as this makes the tubal ligation difficult in the future. The success rate of tubal reanastomosis is only 20%. Patency of the uterine cavity and the tube is visualised by injecting radiopaque material into the uterus, radiologically. It is done with the hysteroscope to examine the endometrium, polyp and the state of uterine ostia. It can be done with the help of laparoscope, after putting an air into the peritoneal cavity. Small loop of the tube clamped by siliastic yoon ring however, stainless steel rings are used in UK. Note: All scopies are good in good hands.

Ovary 693

OVARY Ovary :

Figure 419 Ovary in ovarian fossa and its boundaries

Figure 420 Ovary in broad ligament seen in sagittal section

Figure 421 Showing relations of right ovary

They are the female gonads situated in the true pelvic cavity on the lateral pelvic wall by the side of the uterus and below and behind the uterine tubes. Ovary is enclosed in the posterior layer of the broad ligament by the meso-ovarian. It is 3 cm long , 1.5 wide and 1 cm thick. It presents two surfaces, two borders and two poles. Anterior border is attached to the meso-ovarian. Its tubal pole is related to the external iliac vein and the suspensary ligament of the ovary. Posterior border is free and is related to the ureter and the internal iliac artery. Tubal end presents fimbria which are finger like processes arising from the infundibulum. Uterine end of the ovary is attached to the uterus by ligament of ovary. Lateral surface is related to obturator internus muscle, obturator fascia and the obturator vessels and the nerve. It is easier to remember all the relations, if one says, “Lateral surface of the ovary is related to all obturator, i.e. obturator muscle, obturator fascia, obturator vessels and nerve. Medial surface is related to ampullary part of the uterine tube (Figures 419 to 421).

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Position of the Ovary:

Blood Supply:

Venous Drainage: Lymphatic Drainage: Nerve Supply: Development of Ovary:

Histology:

Clinical:

Position of the ovary changes with the advancement of the pregnancy, as the uterus becomes an abdominal organ. After termination of the pregnancy uterus involutes and the ovary occupies normal place. However, it is not a static organ and is known for its wandering. Ovary is found prolapsed in the pouch of Douglas even in normal women. Ovarian artery the branch of abdominal aorta supplies the ovary. The origin of the ovarian artery is near the origin of the renal arteries. It enters the broad ligament through the infundibulopelvic ligament. Right ovarian vein drains into the inferior vena cava while the left drains into the left renal vein. Lymphatic of the ovary drain into the lateral and pre-aortic group of lymph nodes. It comes from the plexus (T10, and 11th thoracic spinal segments and come from the renal and aortic plexuses. It is mesodermal in origin and develops from the genital part of urogenital ridge on the posterior abdominal wall. Primordial germ cells comes from the wall of the yolk sac. Ovary develops in the lumbar region, descends in the pelvic cavity and stops there due to the attachment of the gubernaculum to the uterine cornu. The part of the gubernaculums between the ovary and uterine cornu is known as the ligament of the ovary. Peritoneal is modified over the surface of the ovary in the form of germinal epithelium. Under it lies the fibrous layer known as tunica albuginea. Cortex of the ovary presents grafffican follicles, corpus lutea and the corpus albicans. Lying inside the cortex is the medulla. In the cortex number of interstitial cells are seen during prenatal life. It must be remembered that these cells are present in the atretic follicles after puberty. However, the germinal epithelium disappears in adult and the tunica albuginea remains the sole fibrous cover. In old age ovaries get atrophied and the follicles disappears. 1. Ovarian cyst: They are of two types follicular and leuteal. 2. Krukenburg tumour: It is seen in the carcinoma of the breast and the carcinoma of the stomach. 3. Meig’s syndrome: It is associated with ascitis, pleura effusion and solid fibroma of the ovary. Removal of the ovarian fibroma curves the condition, e.g. effusion and ascitis both disappear. 4. Twisted ovarian cyst : It can be an emergency as ovarian pedical obstructs the blood supply and the venous drainage of the cyst. 5. Polycystic ovary syndrome (PCOS): Tunica albuginea is thick and there is failure of ovulation. Woman has menstrual disorders, hirsutism, amenorrhoea, balding and high levels of androgen. They are prone to develop carcinoma of breast and cardio-vascular diseases. Ovarian cyst can be of a very large size and at times becomes difficult to differentiate from the ascitis. Due to high intra-abdominal pressure, patient develops hiatus hernia and varicosities of the lower limb. Ectopic ovarian pregnancy is very rare however, it is recently reported from Australia, where the live birth has been recorded.

Urethra

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URETHRA Male Urethra:

The male urethra begins at the internal urethral orifice of the urinary bladder and ends at the external urinary meatus at the glans penis, which is the narrowest part of the male ureter. Its length is about 20 cm. During its course it runs downwards forwards and downwards (when the penis is dependent). It is divided into three parts the prostatic, membranous and the penile. Structure of the Urethra (Figure 422): 1. Outer coat is made of fibroelastic tissue with a few muscle fibres, 2. Submucous coat, 3. Mucous coat—Mucous coat has urethral lacunae the openings of which are directed anteriorly. If a urethral dilator enters the lacunar opening, the false passage is created. Submucous coat presents number of urethral glands known as periurethral glands. Infected periurethral glands form microabscesses around the urethra in gonorrhoea. Healing of the micro-abscess is followed by the urethral stricture.

Figure 422 Male urethra

Lining of Urethra:

Female Urethra:

Lining of Female Urethra:

Portion of the urethra above the ejaculatory duct is lined by the transitional epithelium. Terminal portion is lined by stratified squamous epithelium and the middle portion is lined by columnar epithelium. Terminal part of the urethra is dialated and is known as fossa navicularis which presents the lacuna magna in its roof. It is one and half inch (3.25 cm) in length. Due to its short length urinary infections are more common in female than in the male. It is wider than the male urethra. Anteriorly, it is related to the pubo-vasical ligaments and the symphysis pubis. Posteriorly, it is related to the vagina as it is embedded in the anterior wall of vagina itself. It is made of the three layers, i.e. muscular, submucous and mucous. Paraurethral ducts open at the margin of its external urethral opening. Urethra opens into the vestibule of the vagina little infront of the vaginal orifice. The female urethra is lined by the transitional epithelium. This part corresponds to the prostatic part of the urethra of male above the colliculus seminalis.

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Clinical:

During obstructed labour foetal head can compress the urethra against the symphysis pubis and causes its necrosis — leading to the formation of the urethro-vaginal fistula. Female urethra passes through the anterior vaginal wall. Old age, multiple pregnancies, sexual intercourse and the unhygenic habits lead to periurethral fibrosis. Urinary bladder does not get completely emptied and patient has an incomplete sense of evacuation. (Indian female urethritis — It can be treated by dilatation under local or general anaesthesia). Note on female urethra: There is no true sphincter for the female urethra. Urethra is highly encircled by the cross spiral muscles which help in closure of the urethral orifice. It can be compared to tight coiled spring. When the coiled spring is pulled up it losses resistance, and the urethra opens. When the detrusor of the bladder contract it pulls up the spiral fibres around the urethra resulting in opening of the urethra from above downwards. It is mainly due to the polarity of the bladder and urethra similar to that of the uterus.

Internal Iliac Artery

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INTERNAL ILIAC ARTERY It is one of the two terminal branches of the common iliac artery. It arises at the level of the lumbo-sacral disc and runs downwards up to the upper border of the greater sciatic foramen where it divides into the anterior and the posterior divisions. Relations of the Artery :

Anterior: Ureter in male and the ovary and fibriated end of the uterine tube in female. Medial: Peritoneum separating it from the terminal ileum on the right and the sigmoid on the left. Lateral: Obturator internus, external iliac vein and the obturator nerve (Figures 423A and B; and 424). Posteromedial: Internal iliac artery, internal iliac vein, the lumbo-sacral trunk and sacroiliac joint. Posterior: Sacrum, the sacroiliac joint, iternal iliac vein, lumbo-sacral trunk. Branches of the posterior division: Ilio-lumbar, lateral sacral, superior gluteal (SIL), S – Superior glueteal

Figure 423A Showing branches of the anterior and the posterior divisions of internal iliac arteries in male

Figure 423B Showing internal pudendal artery

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Figure 424 Showing course of internal pudendal artery and its branches

Anterior Division:

I – Ilio-lumbar, L- Lateral sacral. Branches from the anterior division: They are six in numbers. 1. Obliterated umbilical: It gives superior vesical and continues as lateral umbilical ligament. 2. Obturator artery. 3. Inferior vesical. 4. Middle rectal. 5. Inferior gluteal. 6. Internal pudendal. Aid to memory: It is difficult to remember the branches of the anterior division of the interior iliac artery serially. The following sentence if remembered becomes the key for the remembering the branches of the anterior division of the internal iliac artery. “O, O, IM, GENERAL PRACTITIONER”. O - Obliterated umbilical O - Obturator I - Inferior vesical M - Middle rectal G - Gluteal (inferior) P - Pudendal (internal) It is important to note that in female, the inferior vesical artery is absent. It is replaced by two arteries namely the uterine and the vaginal. Distribution of branches of internal iliac artery: 1. Obliterated Umbilical (Superior vesical artery): Obliterated umbilical artery gives branch to the urinary bladder known as superior vesical artery. Superior vesical artery in the male gives the artery of the vas. It reaches the testis along with the vas and anastomoses with the testicular artery. It also supplies the ureter. Superior vesical artery represents the proximal patent part of the umbilical artery. 2. Inferior vesical artery: Arises near the middle rectal artery. It supplies bladder, prostate, seminal vesical and the ureter. It may give the artery of the vas. 3. Middle rectal artery: Middle rectal artery arises with the interior vesical artery and supplies the muscular coat of the rectum. Middle rectal artery anastomoses with the superior and the inferior rectal arteries. It supplies the seminal vesical and the prostate.

Internal Iliac Artery Uterine Artery:

Vaginal Artery:

Obturator Artery:

Internal Pudendal Artery:

Clinical:

699

As it arises from the anterior division of the internal iliac artery, it runs medially on the levator ani muscle. About 2 cm from the cervix it crosses the ureter from above near the lateral vaginal fornix. Here it gives a branch to the ureter. It runs in the broad ligament along the lateral border of the uterus giving branches to the body of the uterus all along. At the junction of uterus and the tube it turns laterally to go towards the hilum of the ovary and anastomoses with the ovarian artery. It supplies the uterus, uterine tubes and the round ligament of uterus. Lower down it gives branches to the cervix and descends to form azygos arteries of the vagina by joining the vaginal arteries. There are two azygos arteries of the vagina one anterior and other posterior. Muscular branches to the uterine muscle are tortuous and are known as helicine arteries. They are double or triple and morphologically, it correspondes to the inferior vesical artery of the male as it arises from the anterior division of the internal iliac artery. It descends on the vagina and gives branches to the mucus membrane, vestibule of bulb, and to the part of the rectum. It helps in forming the azygos arteries of the vagina. It runs on the lateral pelvic wall up to the obturator foramen. It enters the obturator canal after living the pelvic cavity and divides into anterior and the posterior branches. In the pelvis it lies on the obturator muscle, obturator fascia laterally. Medially, it is crossed by the ureter and the vas deferens under the pelvic parietal peritoneum. The obturator artery gives branches in the pelvic fossa supplies the bone, iliacus muscle and anastomoses with the ilio-lumbar artery. It also gives a vesical branch which supplies the urinary bladder. Before living the pelvic cavity it gives the pubic branch which anastomoses with the pubic branch of the inferior epigastric artery on the pelvic surface of the body of pubis. In 30% of the cases the anastomosis is enlarged and forms the abnormal obturator artery. As it comes out of the pelvic cavity it divides into anterior and the posterior branches. Posterior branch follows the posterior margin of the obturator foramen and anastomoses with the anterior and also with the inferior gluteal artery. Acetabular branch comes from the posterior division which passes through the acetabular notch and supplies the ligamentum teres femoris. It is the smaller branch of the anterior division of the internal iliac artery than the inferior gluteal. The internal pudendal artery supplies the external genitalia. It is smaller in female. In pelvis the internal pudendal artery crosses the piriformis, sacral plexus and the inferior gluteal artery superficially. The internal pudendal artery gives the inferior rectual artery 4 cm above the ischial tuberosity. The inferior rectal artery leaves pudendal canal and supplies the skin and the musculature of the anal canal. Inferior rectal artery anastomoses with the similar branch of the opposite side and communicates with the superior, middle rectal arteries. It may form an anastomosis with the perineal arteries. Developmentally it is the umbilical artery of the foetus. It is required to be ligated in the management of postpartum haemorrhage.

BRANCHES OF THE INTERNAL PUDENDAL ARTERY Perineal Artery :

Perineal artery leaves the company of internal pudendal artery at the anterior end of the pudendal canal runs downwards and pierces the urogenital diaphragam. It supplies the bulbo-spongiosus and ischiocavernosus muscles. It gives transverse branch which passes medially

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Artery of the Bulb of Penis: Urethral Artery:

Deep artery of Penis: Dorsal Artery of the Penis:

Dorsal artery of the Clitoris:

Inferior Gluteal Artery: Branches of the Posterior Division of the Internal Iliac artery:

Figure 425 Schematic diagram showing course and relations of iliolumbar artery

below the superficial transverse perini muscle to anastomose the similar branch of the opposite side. It supplies the posterior part of the scrotum. Posterior scrotal arteries supply the skin of the scrotum and the dortus muscle. They usually arise from the perineal but may arise from the transverse branch. The artery of the bulb passes medially through the deep transverse perineal muscle and reaches the bulb of the penis after piercing the perineal membrane. It supplies the posterior part of corpus spongiosum and the bulbo-urethral gland. The urethral artery passes through the fascia of the urogenital diaphragms and enters the corpus spongiosum and reaches the glans penis. It is distributed to the urethra and the erectile tissue. The deep artery of the penis is one of the two terminal branches of the internal pudendal artery which enters the crus penis. It supplies the corpus cavernosum and the erectile tissue. The dorsal artery of the penis is one of the two terminal branches of the internal pudendal artery. It ascends between the crus penis and the symphysis pubis, enters the suspensary ligament of the penis and runs along the dorsum of the penis to reach the glans. At the glans it divides to give branches to the glans penis and the prepuce. Deep dorsal vein of the penis runs on the dorsum of the penis in the median plane. It is flanked by the dorsal artery and the dorsal nerve of the penis on either side, nerve being the lateral. Dorsal artery of the clitoris is one of the two terminal branches of the internal pudendal artery. In female the internal pudendal artery is smaller. However, its branches are similar including the posterior labial branches and the artery of the bulb. Deep artery of the clitoris supplies the corpus cavernosum and the glans and prepuce of the clitoris. Inferior gluteal artery is the larger terminal branch of the anterior division of the internal iliac artery which mainly supplies the gluteal region and the thigh. 1. Ilio-lumbar (Figure 425): Ilio-lumbar artery is the branch of the posterior division of the internal iliac artery. It goes laterally and upwards infront of the sacro-iliac joint and the lumbo-sacral trunk but behind the obturator nerve and the external iliac vessels. It reaches the medial border of the psoas major muscle and divides into the lumbar and the iliac branches.

Internal Iliac Artery

Superior Gluteal Artery:

701

The lumbar branch anastomose with the fourth lumbar artery. It gives muscular branches to the psoas major and the quadratus lumborum muscles. It gives a spinal branch which passes through the intervertebral foramen between L5 and S1 and supplies the cauda equina. The iliac branch passes under the iliacus muscle and the bone. It gives a nutrient branch to the ilium. Further its branches cross the iliac crest and anastomose with superior gluteal, circumflex iliac and the lateral femoral circumflex arteries. Clinical: In case of the fracture dislocation of the sacro-iliac joints, iliolumbar artery which forms an anterior relation of the joint gets torned and bleeds. The bleeding from the ilio-lumbar artery is in the retroperitoneal space and can be alarming and may cause the death. 2. Lateral sacral arteries: They are two the superior and the interior. Each divides into two and enter the anterior sacral foramina. They supply interior of the sacral canal and come out on the dorsum of the sacrum through the posterior sacral foramina. It is the largest branch of the internal iliac artery and supposed to be continuation of the posterior division. It runs backwards between the lumbo-sacral trunk and the 1st sacral ramus and leaves the pelvis through the greater sciatic foramina above the piriformis muscle. (Inferior branch of the superior gluteal artery anastomoses with the lateral femoral circumflex artery).

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INTERNAL ILIAC VEIN It is formed by the veins accompanying the branches of the internal iliac artery except the iliolumbar vein which joins the common iliac vein on either side. It runs from the upper margin of the greater sciatic foramen to join the external iliac vein to form the common iliac vein in front of the sacroiliac joint. Veins from the pelvic venous plexus like bladder, prostate, ureter vagina and the rectum join the internal iliac vein. (In short it drains the venous blood from all the pelvic organs) (Figure 426). Figure 426 Showing tributaries internal iliac vein in male

Sacral Plexus

703

SACRAL PLEXUS Sacral plexus is formed by the parts of the lumbar 4th, 5th and sacral 1st, 2nd, 3rd and 4th. The plexus lies in front of the piriformis muscle behind the parietal layer of the pelvic fascia, internal iliac vessels and its branches, namely the lateral sacral, inferior gluteal and the internal pudendal. The rectum forms the important anterior relation of the sacral plexus (Figure 427). Following are the branches given by the plexus: 1. The superior gluteal nerve (L4, 5 and S1). 2. Inferior gluteal nerve (L5, S1 and 2). 3. The nerve to quadratus femoris (L4, 5 and S1). 4. The nerve to obturator internus (L5, S1 and 2). 5. The posterior cutaneous nerve of thigh (S1, 2 and 3). 6. The sciatic nerve (L4, 5, S1 and 2 and 3). 7. The pudendal nerve (S2 and 3 and 4). 8. Branches to the piriformis (S2 and 3). 9. The pelvic splanchnic (S2 and 3 or S3 and 4). 10. The perforating cutaneous nerve (S2 and 3). Figure 427 Showing sacral plexus

Clinical:

Sciatic nerve is the thickest nerve of the body which is provided with the tough fascial sheath. It has two components the common peroneal and the tibial. Sciatic nerve is supplied by the branch of the inferior gluteal artery known as arteria nervi ischidia. During amputation of the thigh the above artery is likely to bleed profusely. Pain along the distribution of the sciatic nerve is known as sciatica. Sciatica is not a disease but a symptom. There are three T’s which can compress the sciatic nerve. T - Trauma T - Tumour T - Tuberculosis

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Note on Development of Vertebral Column:

Clinical: Occygeal Plexus:

Pelvic Position of the Sympathetic Chain:

Paraxial mesoderm is placed by the side of neural tube. It gets divided into the sclerotome and the dermomyotome. Dermomyotome forms the muscles of the back while the sclerotome which is placed medially surrounds the neural tube on both the sides and forms the vertebra. Nonunion of the posterior arch of the vertebral canal is known as spina bifida. When only the meninges herniate through the gap under the skin it is known as meningocoel. In case of the presence of the spinal cord in the herniated part is known as meningomyelocoele. Spina bifida is associated with stenosis of the aqueduct of the mid-brain which causes hydrocephalus. (Dilatation of the ventricals of the brain.) Involvement of the sacral plexus in advanced carcinoma of the rectum gives severe pain along the distribution of the nerves. Part of the fourth sacral, fifth sacral and the occygeal nerve form this plexus. It lies in front of the coccygeus muscle and give branches to the levator ani, coccygeus and the sphincter ani externus. It lies on the anterior surface of the sacrum and medial to the anterior sacral formina. Normally it has four ganglia. Right and the left sympathetic chains unite in front of the coccyx to form, the ganglion impar.

Joints of the Pelvis

705

JOINTS OF THE PELVIS SACRO-ILIAC JOINT Classification: Synovial and of plane variety. Bones taking part: Auricular surfaces of the sacrum and the ilium. Ligaments : Anterior and the posterior sacro-iliac and the interosseous sacroiliac ligaments. Relations: Anterior: Anterior relations are abdominal and pelvic. 1. Abdominal: Psoas major and iliacus muscles, femoral nerve, obturator nerve and the ilio-Iumbar artery are the anterior relations. 2. Pelvic-relation: Lumb-sacral trunk, first sacral nerve, upper part of piriformis muscle, internal iliac vein and the posterior division of the internal iliac artery. Superior gluteal artery as it passes between the lumbosacral trunk and the first sacral nerve lies in front of the joint. Relation of the nerves are important as they are likely to get involved in traumatic dislocation of the joint. Posterior relations : 1. Sacrospinalis muscle, 2. Gluteus maximus muscle.

CLINICAL Tuberculosis of Sacro-iliac Joint:

Sacro-iliac Strain:

Sacro-iliac joint is placed in the middle and transmits 50% weight of the body. Even if the head or the toe moves there is bound to be some movement in the joint. In case of tuberculosis of the sacro-iliac joint, instead of giving plaster from head to toe, joint is opened from behind and the sacrum and the ilium, are fixed with the help of bony piece (Orthrodesis). Rest to the part is the principle in the treatment of tuberculosis. During pregnancy the ligaments of the sacro-iliac joints become lax, which affects the locking mechanism of the sacro-iliac joint. After delivery the locking mechanism returns and the ligaments get tightened. However, this occurs in the position adopted during the pregnancy. Failure of locking of the sacro-iliac joint puts strain on the ligaments resulting in sacro-iliac sub-luxsation. As a result the ligaments are subjected to the strain and patient complains of pain in the sacro-iliac joint, which can be unilateral or bilateral. Symphysis pubis: This is a secondary cartilaginous type of joint. Bones taking part: These are the symphyseal surfaces of pubic bones. The surfaces are covered with the hyaline cartilage and are connected by the fibrocartilaginous disc. Ligaments: 1. Anterior, 2. Posterior, 3. Superior, and 4. Inferior pubic ligaments.

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Sacral Canal :

Caudal Block:

Sacral canal is the triangular canal wider in its upper part and it narrower in the lower. It opens through the sacral hiatus. Dural sheath of the spinal cord ends at the spine of second sacral vertebra. Filum terminale runs from the cones medularis, pierces the dural sheath, comes out of the sacral hiatus and gets attached to the dorsum of the first piece of the coccyx. The extradural space in the sacral canal is called as the epidural space. Caudal block anesthesia is given through the sacral hiatus into the epidural space for painless labour. Following are the contents of the sacral canal : 1. Lower limit of the dura and archnoid, 2. Roots of the 5 sacral nerves and first coccygeal nerve, 3. Filum terminale, 4. Blood vessels and fat. Dura and the archnoid end at the second sacral spine. Structures which come out of the sacral hiatus are: 1. Filum terminale, 2. Fifth sacral nerve, and 3. First coccygeal nerve. Note: Why not remember as CSF C- for coccygeal, S- for sacral, and the F- for Filum. Anaesthetic agent can be injected in the epidural space of the sacral canal through the sacral hiatus for painless labour, which is not popular this days.

Muscles of the Back

707

MUSCLES OF THE BACK Erector Spinae (Sacrospinals) (Figures 428 and 429):

Following are the muscles of the back: Erector spinae muscle is placed in the groove on the sides of the vertebral column. It is under cover of the lumbar fascia, serratus posterior inferior below and the rhomboid and the splenius muscles above. In the sacral region it is tendinous. This muscle forms the fleshy mass in the lumbar region where its surface identification is evident. Lateral border of this muscle is marked by the groove which can be seen on the surface. It runs upwards and crosses the ribs at their angles. It arises from the back of the sacrum, spines of the lumbar and the 11th and the 12th thoracic vertebrae. It arises from the supraspinus ligaments, iliac crest and the sacrotuberous ligaments. Its upper part is arranged into three different columns. They are the lateral, intermediate and the medial. Lateral group is further divided into three, namely the iliocostalis lumborum, iliocostalis thoracis and the iliocostalis cervicis. Intermediate group is divisible into three columns, namely the longissimus thoracic, cervicis and the capitis. The medial group is also arranged in three columns, namely the spinalis thoracis, cervicis and the capitis.

Figure 428 Lumbar fascia

Figure 429 Showing lumbar fascia

Nerve Supply: Actions: Clinical:

Dorsal rami of the lower cervical, the thoracic and the upper lumbar nerves supply the muscle. Sacro-spinalis is an extensors of the vertebral column. They do play a role in lateral flexion of the column. Physiotherapy for the intervertebral disc prolapse includes extension exercises of the muscles of the back.

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LUMBAR FASCIA

Clinical:

The deep fascia in the lumbar region is known as the lumbar fascia. It is thick tough and fibrous in nature. Lumbar fascia is arranged into three layers. The anterior, middle and the posterior. The posterior layer is attached to the spinous process of the lumbar and sacral vertebrae and to the supraspinous ligaments. The middle layer is attached, to the tips of the transverse processes of the lumbar vertebrae and to the inter-transverse ligaments. It is attached to the iliac crest below and the lower border of the 12th rib and the lumbocostal ligaments above. The anterior layer covers the quadratus lumborum muscle and is attached medially to the anterior surface of the transverse processes of the lumbar vertebrae. It is attached below to the ilo-lumbar ligament and the adjoining part of the iliac crest. Higher up it forms the lateral lumbocostal arch. The middle and the posterior layers unite at the lateral border of the sacrospinalis muscle. The fused layers join the anterior layer at the lateral border of the quadratus lumborum muscle gives origin to the transversus abdominis muscle. Between the posterior and middle layers lies in the sacrospinalis muscle, while the anterior and the middle layers enclose the quadratus lumboram muscle. Between the lateral border of sacrospinalis and the 12th rib is the renal angle. The bulging of the perinephric abscess is noted first, at the renal angle. In pyelonephritis renal angle is tender.

Surface Marking of Important Structures 709

SURFACE MARKING OF IMPORTANT STRUCTURES Stomach Cardiac Orifice: Pyloric Orifice: Lesser Curvature:

Greater Curvature:

Kidney:

Ureters:

Spleen:

Portal Vein:

Left 7th coastal cartilage 2.5 cm from the median plane. Draw two short parallel lines 2 cm apart sloping downwards and to left. A point on transpyloric plane 1.25 cm to right side from median plane. Draw two short parallel lines 2 cm apart from this point inclining upwards and to right side. J shaped line extending from right margin of cardiac orifice to upper margin of cardiac orifice to upper margin of pyloric orifice. Most dependent part of line lies just below transpyloric plane. A point on the left 5th intercostal space slightly below and medial to the left nipple. A mid-point of junction between 9th and 10th costal cartilage. Draw a curved line extending upwards and to left – from left margin of cardiac orifice to lower margin of pyloric orifice. 1. Take a point 5 cm lateral to the mid-line on transpyloric plane. 2. Draw a curved line 2.5 cm with medial concavity for right kidney line extends downwards and for left kidney it extends upwards. 3. Take a point 4 cm above the upper end of curved line and 2.5 cm lateral to median plane. 4. Take a point 4 cm below the lower end of curved line and 7.5 cm from the median plane. 5. Take a point 5 cm lateral to 1st point or transpyloric plane. - Join the hilar concavity with adjacent 3rd and 4th points with the convexity directed medially. - Finally join the 3rd and 4th points by a line with outward convexity which passes through 5th point. 1. Draw the concavity of hilum of kidney. 2. A point 5 cm below the transpyloric plane and same distance lateral to mid line. 3. A line joining mid-inguinal point and a point 1.2 cm below and to the left of umbilicus. Take a point at the upper 1/3rd and lower 2/3rd of this line. 4. A point on the pubic tubercle. Spleen from posterior aspect 1. Point 4 cm lateral to 10th thoracic spine. 2. A point on 10th Rib on Mid-axillary line. 3. Join these points by avoiding lines overlapping 9th and 11th Rib superiorly and inferiorly respectively. Kidney posteriorly (Morris parallelogram): 1. 2 horizontal lines passing through T11 and L3 spines. 2. 2 vertical lines 2.5 cm and 9 cm apart. The areas mapped between these lines is called as Morris parallelogram. Mark a point on the transpyloric plane 1.2 cm to the right of the median plane. Draw a broad line from this point to the right and upwards having 8 cm length.

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CLINICAL PICTURES Figure 430 Laparoscopic view of gallbladder

Figure 431 Showing omphalocele

Figure 432 Showing hypospadius

Clinical Pictures Figure 433 Showing laparoscopic removal of appendix

Figure 434 Showing Intravenous pyelography

Figure 435 Showing barium swallow of oesophagus

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Figure 436 Showing barium picture of large intestine

Figure 437 Showing kidneys in ultrasonography

Figure 438 oesophageal varices

Clinical Pictures Figure 439 Showing gallbladder and common bile duct in ultrasonography

Figure 440 Gastric mucosal folds

Figure 441 Carcinoma penis

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Figure 442 Exstrophy of bladder (Ectopia vesicae)

Figure 443 Laparoscopic view of normal uterus and ovary

Figure 444 Horse shoe kidney

Clinical Pictures Figure 445 Coronary angiography showing left coronary artery

Figure 446 Coronary angiography showing right coronary artery

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Index

i

INDEX A

C

Abdomen 522 divisions 522, 523 surface landmarks 522 Abdominal aorta 636 branches 637 paired 638 unpaired 637 Abdominal cavity greater sac 558 lesser sac 559 Aberrant renal arteries 609 Abnormal obturator artery 540 Achalasia cardia 474 Acute pancreatitis 596 Acute retention of urine 671 Addison’s hypocorticism 612 Agenesis 425 Amoebic liver abscess 580 Ampulla of Vater 589 Anal canal 500, 660 musculature 661 Anal fissure 663 Anal triangle 495 Aneurysm 457, 638 Annular pancreas 592, 596 Anorectal ring 662, 664 Aortic knuckle 454 Aortic orifice 440 Appendicitis 658 Arch of Rolan 635 Artery of the penis 509 Artificial kidney 610 Ascending colon 630 Atresia 474, 549 Atrial myxomas 440 Azoospermia 557 Azygos vein 480

Caecostomy 626 Caesarean section 687 Callot’s triangle 585 Cancer of the apex of the lung 424 Cantlie’s line 574 Caput medusae 525 Carcinoma bladder 672 gallbladder 585 liver 580 oesophagus 474 rectum 658 scrotum 517 caecum 626 cervix 687 colon 635 duodenum 592 head of the pancreas 596 penis 514, 713 stomach 567 Cardiac pain 447 Cardiac plexuses 449 Cardiac sphincter 476, 647 Cardiomyopathy 443 Cardiopulmonary resuscitation 447 Cathartic colon 633 Cauda equine 371 Caudal block 706 Caval-caval shunt 642 Cervical rib 364 Cholecystitis 584 Cholecystography 584 Choledocal cysts 585 Cholelithiasis 584 Chronic pancreatitis 596 Chylothorax 404 Cirrhosis 579 Cisterna chyli 644 Coarctation of aorta 457, 458, 464 Coccydynia 372 Coccyx 372 Coecal recesses 629 Coeliac ganglion 644 Collateral venous circulation 641 Colonoscopy 635 Compression test 365 Congenital megaureter 619 Congenital pyloric stenosis 549 Constrictive pericarditis 429 Copper T and loop 687 Coronary arteries 443, 715 branches 445 left 445 right 443

B Barium swallow of oesophagus 711 Barrel chest 424 Barret’s oesophagus 474 Bartholin’s cysts 521 Bartholin’s gland 519, 521 Batson’s plexus 670 Bile duct 583 Bleeding per rectum 658 Boerhaave syndrome 474 Bowari’s operation 618 Brachiocephalic vein 485 Bronchi 414 Bronchiectasis 424 Brunner’s gland 500 Bulbo-spongiosus 506, 519

Coronary bypass surgery 446 Coronary sinus 448 Costo-vertebral joints 491, 492 Courvoisier’s law 585 Cremaster muscle 532 Cremasteric reflex 532 Crow’s feet 562 Crus of the penis 507 Curling’s ulcer 590 Cystic duct 583 Cystic vein 599 Cystitis 671 Cystocele 672 Cystoscopy 672

D D and C 687 Deep circumflex iliac artery 540 Deep crural arch 536 Deep inguinal ring 537 Deep perineal pouch 508 Descending colon 631 Development of lungs 425 Dextrocardia 451 Di George syndrome 487 Diaphragm 645 intraperitoneal spaces 648 openings 645 aortic 645 oesophageal 645 opening of the inferior vena cava 646 openings of surgical importance 646 vertebro-costal triangle 646 Diseases of heart 446 Divarication of the recti 535, 546 Diverticulitis 635 Diverticulosis 635 Diverticulum of the urinary bladder 672 Double ureter 618 Duodenal cap 590 Duodenum 587 histology 590, 591 peritoneal recess 591 peritoneal relation 587 first part 588 fourth part 589 second part 588 third part 589 radiological appearance 590 Dysphagia lusoria 474 Dyspnoea 382 Dysurea 676

ii Kadasne’s Textbook of Anatomy (Clinically Oriented) E Eaton-Lambert syndrome 424 Ectopia cordis 451 Ectopia vesicae 671, 714 Ectopic pregnancy 692 Ectopic testis 554 Elephantiasis 480 Embolism 623, 638 Empyema 404 Epididymis 557 Epididymo-orchitis 557 Epigastric artery 539, 540, 541 Exomphalos 544

F Family planning 692 Fascia lunata 496 Colles 502, 503 Denonvillier 664, 656, 676 Scarpa 526 Waldeyr 658 transversalis 536 Female perineum 519 Female urethra 520 Femoral canal 544 Fertilized ovum 682 Fibroids 688 Fissures of the lung 422 Fistula in ano 664 Floating ribs 361 Foetal circulation 459 Foramen Morgagni 646 Winslow 561 Formation of bands 549 Fournier’s gangrene 517 Fracture of penis 514 Functions of colon 629 Functions of the peritoneum 560

G Gallbladder 582 anomalies 586 development 585 function 582 structure 582 Gallstone 584 Ganglio-neuroma 394 Gartner’s duct 682 Gastric mucosal folds 713 Gastric vein 599 Genitalia of the female 520 Goodsall’s rule 664 Grey Turner’s sign 596

H Haemorrhoids 663 Haemothorax 404 Hasselbach’s triangle 538

Heart anatomy 431 AV node 442 base 433 borders 431 conducting system 442 diaphragmatic surface 433 fibrous base 441 left atrio-ventricular orifice 439 left ventricle 438 ligamentum arteriosum 438 moderator band 435 functions 436 musculature of the atria 442 posterior relations 433 pulmonary opening 437 pulmonary trunk 437 pulmonary valve 437 right atrioventricular opening 437 right atrium 433, 434 right pulmonary artery 438 right ventricle 435 sternocostal surface 431, 432 structure 441 Hemiazygos vein 481 Hepatitis 580 Hernia 542 direct inguinal 544 epigastric 545 femoral 544 gluteal 545 hiatus 474, 646 inguinal 542 lumbar 545 obturator 545 paraumbilical 545 sciatic 545 spigelian 545 umbilical 544, 545 Herniation of bladder 672 Herniotomy 545 Hiatus of Schwalbe 499 Hidradenitis suppurativa 664 Hilar dance 459 Hilum 607 Hirsprung’s disease 633 Holden’s line 526 Horse shoe kidney 609, 714 Hurricane tumour 556 Hyaline membrane disease 424 Hydatid cyst 579 Hydatid of Morgagni 556 Hydrocele 517 Hydronephrosis 618 Hydro-pneumothorax 404 Hymen 689 Hypernephroma 611 Hypospadias 518, 710 Hysterectomy 687 Hysterosalphingography 687, 692 Hysteroscopy 692

I Iliac crest 522 Iliac veins 640 Iliocaecal tuberculosis 626 Imperforate anus 549 Indian female uretheritis 520 Inferior vena cava 484, 639 relation 639 tributaries 640 Inguinal canal 538 Inguinal ligament 522 Inguinal triangle 538 Intercostal artery 462 Intercostal vein 482 Intercostobrachial nerve 386 Internal herniation 623 Internal iliac artery 697 Internal iliac vein 702 Internal pudendal artery 699 artery of the bulb of penis 700 deep artery of penis 700 dorsal artery of the clitoris 700 dorsal artery of the penis 700 iliac artery 700 inferior gluteal artery 700 perineal artery 699 superior gluteal artery 701 urethral artery 700 Internal thoracic mammary artery 387, 388 Interventricular septum 441 Intervertebral joints 491 Intrapulmonary bronchus 419 Intravenous pyelography 711 Intussuseption 623 Inverted testis 553 Ischio-rectal abscess 499 Ischio-rectal fossa boundaries 496 contents 499

J Joints of the pelvis 705 Juxtamedullary apparatus 608

K Kidneys 605 capsules 605 congenital anomalies 609 development 608 fixation 605 relation 606 Kissing ulcer 566 Krukenberg’s tumours 567 Kupffer’s cells 579 Kyphosis 425

L Lacunar or Gimernat’s ligament 530

Index Lamina 365 Laparoscopic gallbladder 710 Laparoscopic removal of appendix 711 Laparoscopic tubectomy 692 Large intestine 629 Laryngeal nerve 417 Leriche syndrome 638 Levator ani muscles 655 Ligament of Sir Astley Cooper 530 Ligaments of Tritz 589 Ligamentum arteriosum 458 Linea alba 522 Linea semilunaris 522 Litter’s hernia 623 Liver 573 development 579, 581 functions 573 histology 578 lobes 574 lymphatic drainage 578 peritoneal coverings 577 peritoneal reflections 576 porta hepatis 577 segmental anatomy 577 supports of liver 576 surface 574 Lord’s operation 517 Lumbar canal stenosis 371 Lumbar fascia 708 Lumbar plexus 643 Lung abscess 424 Lungs anatomy 406 border 406 bronchial arteries 411 bronchopulmonary segments 408, 409 costal surface 406 lobes and fissures 408 medial surface 406, 407 mediastinal surface 408 phrenic nerve 411

M Mackenrodt’s ligament 685 Male urethra 511 Mal-rotation of the colon 626 Mayo’s operation 545 McBurney’s point 629 Meatal stenosis 514 Meckel’s diverticulum 525, 622, 623 Mediastinal compression syndrome 395 Mediastinitis 395 Mediastinoscopy 395 Mediastinum 388 anterior mediastinum 393 divisions 389 horizontal section 389 mediastinal shift 395

middle mediastinum 393 posterior mediastinum 394 sagittal section 390 superior mediastinum 390, 391, 392 Megacolon 633 Melanoma of the anal canal 664 Mellory-Weiss syndrome 474 Membranous part of urethra 508 Mesenteric tear 623 Mesenteric vein 599 Mitral stenosis 440 Mobile kidney 610 Murphy’s sign 584 Muscles of the anterior abdominal wall 529 Muscles of the back 707 Myasthenia gravis 487 Myocardial infarction 446 Myocardial ischemia 446 Myocardium 443 Myopathy 424

N Navicular fossa 512 Necrosis 579 Nephrectomy 611 Nerve of Kuntz 490 Nerve of Laterjet 562 Neurofibroma 394 Nezelop’s syndrome 488

O Obturator artery 699 Obturator test 628 Oesophageal varices 712 Oesophagus 466 antero-posterior curvature 467 Ba-swallow-X-ray 472 blood supply 469 development 472 lymphatic drainage 471 oesophageal plexus 469 oesophageal sphincter 473 peristaltic waves 472 relation 468 story of ABC 472 structure 471 venous drainage 471 Omphalocele 710 Orbor vitae uteri 682 Orchidectomy 556 Orchioplexy 554 Organ of Giraldes 557 Ovary 693

P Paget’s disease 514 Pancoast’s syndrome 424

iii

Pancreas 593 histology 595 posterior relations 593 relations of the body 594 Pancreaticamagna 595 Paradox of the testicular tumours 556 Pararectal nodes of Gerota 657 Paraumbilical vein 525 Part of articulated skeleton 362 Patent ductus arteriosus 457 Payer’s patches 621, 622 Pectineal ligament 530 Pedicle 365 Pelvic colon 631 Pelvis 649 anatomy 373 diagonal conjugate 377 male and the female pelvis 374, 376 pelvic cavity 376 pelvic injuries 377 muscles of the pelvic walls 651 coccygeus 651 levator ani muscle 652 obturator fascia 652 obturator internus 651 pelvic fascia 653 piriformis 651 sphincter urethrae muscle 652 visceral pelvic fascia 653 muscular lining of the cavity 650 types 377 Penile erection 514 Penis 511 blood supply 513 body 512 development of 515 erection 513 mechanism 514 ligaments 513 transverse section 511 Peptic ulcer 566 Perianal haematoma 664 Pericardium 426 attachment of the second 428 fibrous 427 ligament of the left vena cava 428 pericardial effusion 429 serous 427 transverse sinus 427 Perineal membrane 503 Perineal muscle 510 Perineum 494 Peyronie’s disease 514 Phagocytic cells 418 Pheochromocytoma 613 Piles 662 in pregnancy 663

iv

Kadasne’s Textbook of Anatomy (Clinically Oriented)

Pleura 399 abscess 404 cavity 399 costo-diaphragmatic recess 403 role 403 effusion 403 layers 399 parts 399 cervical 399 costal 400 costo-diaphragmatic 400 costo-mediastinal line 400 mediastinal 400 Pneumonectomy 409 Pneumothorax 404 Portal hypertension 600 Portal vein 598 Posterior abdominal wall 602 muscles 602 iliacus muscle 604 psoas major 602 quadratus lumborum 603 Pott’s anastomosis 451 Pringel’s maneuver 561, 569 Prolapse rectum 658 intervertebral disc 365 uterus 687 Prostate 673 age changes in prostate 676 blood supply 674 development 676 female homologues of prostate 676 lymphatic drainage histology 675 prostatic part 674 prostatic utricle 674 surface 673 venous drainage 674 Pruritus ani 665 Pseudo-pancreatic cyst 596 Psoas abscess 603 Pubic crests 362, 522 Pudendal canal 497 Pulmonary fibrosis 424 Pulmonary ligament 407, 420 Pulmonary substance 418 Pyloric stenosis 561 Pyothorax 404 Pyramidalis 535

Q Quadrilateral spine 366

R Ramsted’s operation 561 Rectal injuries 658 Rectum 653 blood supply 656

flexures 653 lymphatic drainage 657 mucosal folds 654 peritoneal relations 653 structure 656 Rectus sheath 534 Redudent colon 633 Referred pain 526, 527 Renal angle 609 Renal circulation 607 Renal pain 610 Renal stones 610 Renal transplant 609 Respiratory bronchiole 419 Retractile testis 554 Retrocaecal appendix 628 Retrocaval ureter 619 Retroperitoneal tumours 604 Reversal of blood flow 366 Roots of the lungs 420 Rupture of the urinary bladder 671

S Sacral canal 706 Sacral index 372 Sacral plexus 703 Sacro-iliac joint 705 Sacrum 370 Saint’s triad 585 Scrotum 515 blood supply 516 layers 516 Seat-belt syndrome 623 Seminal vesicles 679 Sequestration of lung 425 Sessile hydatid of Morgagni 557 Sibson’s fascia 363, 400, 406 Sigmoidoscopy 635 Sign of dance 623 Silent appendix 628 Sister Josephs nodules 567 Small intestine 620 contents of the mesentery 620 root of mesentery 620 vascular pattern of mesentery 621 Space of Discii 579 Space of Mall 579 Spermatic cord 550 Sphincter urethrae 508 Spina bifida 371 Spinal shock 670 Spleen 569 anomalies ballances sign 571 enlargement 572 hypersplenism 572 Keher’s sign 572 rupture 571 splenic infarction 571 splenic puncture 572

functions 569 peritoneal covering 570 Splenic flexor 635 Splenic portography 600 Splenic vein 599 Spondylolisthesis 371 Stenosis 549 Sternal angle of Louis 361, 367 Sternal puncture 369 Sternebrae 367 Sternoclavicular joint 367 Sterno-costalis muscle 385 Sternotomy 369 Sternum 361, 366 Stomach 560 capacity 560 development 565 gastro-phrenic ligament 562 gastrosplenic ligaments 562 greater omentum 562 lesser omentum 561 malignancy 567 parts 560 peritoneal covering 563 peritoneal folds 561 posterior gastric nerve 563 structure 565 Subcostal arch 361, 522 Superficial fascia 526 Superficial inguinal ring 531 Superficial pouch 504 perineal 519 Superior vena cava 482 development 484 obstruction 483 Supra-renal gland 612 Surgical incisions of the anterior abdominal wall 546 Sympathetic chain 489 Symphysis 367 Symphysis pubis 362 Synostosis 368 Synovial joints 491

T Tendon of the infundibulum 441 Testis 551 anomalies 553 appendix 551 development 552 histology 552 Tetralogy of Fallot 451 Thoracic aorta 453 arch of aorta 454 ascending aorta 453 descending 453, 460 development 456 histology 455 Thoracic duct 477 development 479 interesting story 479 structure 479

Index tributaries 478 valves 478 Thorax 379 boundaries of the thoracic cage 381 functions 379 internal thoracic mammary artery 386 mechanism of respiration 381 muscles 383 shape 379 thoracic wall 383 Thymoma 487 Thymus 486 birth 486 function 487 relations 486 shape 486 Tortion of the testis 555 Trachea 413 blood supply 414 relations 413 structure 413 Tracheaoesophageal fistula 472, 474 Transverse colon 630 Transversus abdominis 533 Traumatic asphyxia 447 Traumatic rupture of female urethra 520 Trichobazar 568 Triscupid valve 437 Troisiers’s sign 567 Tubectomy 692 Tubercle 522 Tumors pleura 404 testis 556

Typical lumbar vertebra 366 Typical rib 364 Typical thoracic vertebra 365, 366

v

fundus 680 ligaments 683 supports 685 uterine cavity 681

U

V

Umbilical calculus 524 Umbilicus 522, 524 Ureter 615 anomalies 618 constrictions 615 development 618 histology 617 pelvis 615 relations 615 Ureterocele 619 Uretero-ureteric anastomosis 618 Urethra 695 Urethritis 520 Urinary bladder 666 anamolies 671 base 667 cavity 667 development 671 ligaments 669 nerve supply 670 position 666 relations 666 shape 666 structure 669 Urogenital triangle 502 Uterine artery 699 Uterine tubes 691 Uterus 680 cervix 682

Vagina 689 Vaginal artery 699 Vagotomy 566 Vagus nerve in thorax 415 Valves of Houston 654, 658 Vas defferens 677 Vein of Marshal 449 Veins of the superior mediastinum 485 Vertebral foramen 365 Vesical calculus 672 Vitello-intestinal duct 525 Volvulus of caecum 626 von Recklinghausen’s disease 394

W Waldeyer’s fascia 656, 664 Wilms’ tumour 611

X Xiphisternum 522 Xiphoid process 361

Z Zollinger-Ellison syndrome 596 Zygosis 592