Studies on the Foetal Pelves and Observations on the Evolution of the Human Pelves

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"STUDIES ON THE FOETAL PELVES A HD OBSERVATIONS

ON THE EVOLUTION

OF

THE HUMAN PELVES."

Thesis Submitted to th e Glasgow U n iv ersity in. fu lfilm e n t of th e re g u la tio n s l a i d down fo r th e Ph.D. Degree i n Anatomy

By Mrs. SARAH J . SOURI, M.B.B.S., D.G.O. (nee Miss Sarah J . Paul)

7th A pril 1950

ProQuest N um ber: 13870186

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i.

P r e f a c e The ch ap ters which follow embody the r e s u lts o f work c a rrie d out during my s ta y a t Glasgow U n iv e rsity .

I was

fo rtu n a te enough, through the good o ffic e s o f my su p erio rs, and under th e au spices o f th e Government o f In d ia , to have the o p p o rtu n ity to o b tain a Fellow ship fo r t h i s p erio d . I wish to express my most g r a te f u l thanks to P ro fesso r GJi.Wyburn, M.B., D .S e., F .R .F .P .S .G ., F .R .S .E ., fo r h is magnanimous and ready h elp , and h is generous a ttitu d e dur­ ing t h i s p erio d . I am also g r e a tly indebted to Dr* P. B acsich, M.D., D.Sc. , F .R .S .E ., fo r h is continued h elp , which made i t p o ssib le fo r me to complete th is ta s k . His p a tie n t in s tru c tio n and h e lp fu l te c h n ic a l sugges­ tio n s , e s p e c ia lly in th e h is to lo g ic a l and em bryological asp e cts o f th e work, were in v alu ab le. I must also express my thanks to th e follow ing:

Dr.

Govan and Dr. S tru th e rs helped me to o b tain specimens from th e M aternity and C h ild ren 1s H o sp ita ls re sp e c tiv e ly .

Pro­

fe ss o r Yonge and Mr. Parsons granted me sp e c ia l peim ission to c a rry out s tu d ie s on th e prim ate pelves in the Zoology Department, Glasgow U n iv e rsity .

Dr. Archibald Young,

L e c tu re r in Anatcmy, perm itted me to d is s e c t the p elv ic flo o r of a green monkey which was in h is p o ssessio n .

Pro-

fe s s o r Thomas Walmsley o f the B e lfa st U n iv ersity le n t me th e em bryologies1 se c tio n s o f th e 100 mm. p elv ic region (human) through th e C hief o f t h i s Department. To a l l th e tech n ician s as w ell as the s e c re ta rie s in the Department I o ffe r thanks fo r th e i r w illin g a ssista n c e and t h e i r c h e e rfu l c o -o p eratio n . The su b ject fo r th e t h e s i s , being "S tudies on the F o etal P elves and O bservations on th e Evolution of the Human P e lv is ” has been chosen in consequence o f the sev eral problems which have been engaging my mind ever since I joined th e Anatomy Department in Madras in 1940.

Previous

to t h i s I was engaged in c l i n i c a l o b s te tr ic s and general p ra c tic e as a Government d o cto r and had met w ith innumerable cases of d i f f i c u l t d e liv e ry among the South Indian women. I t was during th ese years th a t I decided to make en q u iries in to the causes of th ese sev e ral d e fo rm itie s, c o n tra c tio n s and d isp ro p o rtio n s o f the female p e lv is .

When I was tr a n s ­

fe rre d to th e Anatomy Department I requested my C hief, Pro­ fe s s o r A.A. Ayer, to peim it me to c o lle c t female s k e le ta l p e lv ic m a te ria l to make a com parative and m orphological p elv im etric study of th e female p e lv is .

Through h is en­

couragement and under h is guidance I completed a th e s is on the "Anatomy o f th e P e lv is and th e Reproductive System in th e South Indian Woman in r e la tio n to Pregnancy, P a rtu r­ i t i o n and th e P o s t-n a t* l P erio d ", which was presented to

th e Madras U n iv e rsity as fu lfilm e n t o f th e f i r s t p a rt of th e M aster o f Science degree in Anatomy. In t h i s U n iv ersity I made a sim ila r req u est to my p re se n t C hief, P ro fesso r G.M. Wyburn, who has very kindly perm itted me to complete and present the th e s is to th is U n iv e rsity . The p resen t su b ject has been d e a lt w ith in four sep a rate e n q u irie s which are presented in t h i s work as fo u r d if f e r e n t c h a p te rs.

The f i r s t ch ap ter d e a ls w ith the

study o f 66 f o e ta l s k e le ta l pelves w ith regard to t h e i r sexual and m orphological c h a ra c te rs in th e li g h t o f the modern c la s s i f i c a ti o n of th e female p e lv is by Caldwell and Moloy. The second ch ap ter com prises a study o f th e develop­ ment of the human p e lv is in 7 embryos as seen in m icro­ scopic se c tio n s aid ed , by 3 wax model re c o n stru c tio n s of 23 mm., 42 mm., and 100 mm. C.R.L. specimens and 6 S p a ltih o ltz (A liz a rin stain ed ) specimens o f 51, 90, 105, 147, 180, 190 mm. fo e tu se s. The th ird ch ap ter d ea ls w ith the study o f the fa sc ia and v isc e ra of th e fo e ta l p e lv is . The fo u rth ch ap ter is an attem pt to study the evolu­ tio n of th e human p e lv is by ob servations on th e prim ate s k e le ta l p elv es. The o p p o rtu n ity has been taken o f p resen tin g the

e x tern al p elv im etric measurements o f 20 liv in g Kurumba women (a p re -d r a v id ia n tr ib e ) of the N ilg u ri Wynad d i s ­ t r i c t in South In d ia . Measurements taken on the s k e le ta l p elv ic m a te ria l o f 40 South In d ian Women obtained in th e Anatomy D epart­ ment o f th e Madras M edical College are a lso presented with t h e i r s t a t i s t i c a l fu n c tio n .

A MORPHOLOGICAL STUDY OP 6 4 FOETAL PELVES.

INTRODUCTION. The growth o f th e human p e lv is through i t s phylo­ g en etic and ontogenetic stag es has been analysed by various workers through d if f e r e n t p erio d s and in t h e i r d iffe re n t phases.

In 1876 Je h lin g (1) demonstrated th e presence

o f sexual c h a ra c te rs in th e f o e ta l p e lv is in 136 specimens. S ir A rthur Thomson (2) in 1899 confirmed the fin d in g s of Fehling th a t d iffe re n c e s in form and appearances are such as to enable th e observer to d iscrim in ate between th e p e lv is o f the male and the female as e a rly as th e th ird month or fo e ta l l i f e .

ULn t h i s in stan ce eig h t specimens

were examined. However, w ith th e advent o f modern scien c e, g re a t p ro g ress has been made in th e f i e ld o f o b s te tr ic s , espec­ i a l l y in th e s u b je c t of the female p e lv is .

Caldwell and

Moloy (3) have stan dardised th e com parative o b s te tric values o f the female p e lv is on a m orphological b a s is and from the stan dpoint o f th e se v e ra l mechanisms o f lab o u r. Recent in v e s tig a tio n s on th e s k e le ta l p e lv is c a rrie d out on th e Bantu and Bush specimens published by O.S. Heynes(4) (1944) have been evaluated and described on th e lin e s la id down by Caldwell and Moloy.

In my reoent study (5) o f

th e s k e le ta l m a te ria l or th e South Indian p e lv is the same

c l a s s i f i c a ti o n and grouping have been follow ed.

S c ie n tific

e n q u irie s in to th e growth or th e p e lv is in i t s various stag es are c a rrie d out w ith the so le purpose o f discovering any f a c ts which w ill throw l i g h t on th e way s

and means o f

helping n atu re to b u ild a p e lv is which w ill prove a sa fe gateway fo r human liv e s to e n te r th e world and a t once be p la s tio to re g ain i t s in te g r ity a f te r the puerperium .

Hence

a l l e n q u irie s in to th e study o f th e p e lv is , including the fo e ta l p e lv is , must be d ire c te d towards a uniform b a sis of e la s s lf lo a tlo n .

The p resen t work i s an endeavour to study

a s e r ie s of f o e ta l pelves o f known sex and age p erio d , ta k ­ ing in to account the various fa o to rs emphasised in th is c la s s i f i c a ti o n . Morton and Heyden (6) have been c o n trib u tin g a s e rie s o f a r t i c l e s in the American Journal o f O b s te tric s and Gyn­ aecology, on th e com parative study o f the female and male p e lv is in c h ild re n , in p u rsu it of th e e tio lo g y o f pelvic conform ation.

During t h i s d isc u ssio n they r e c a ll th e

o rig in a l v aluable work o arried out by S ir A rthur Thomson (7 ), b u t seem re lu c ta n t to accept h is conclusions on the sexual v a ria tio n s in th e f o e ta l p e lv is in view of th e small number o f speoimens examined. F.L . Reynolds 18), w ritin g on the measurement o f the p e lv is (bony g ird le ) in e a rly infancy, oomments th u s :"Komkow in 1894 oould find no sexual d iffe re n c e s in e x te rn a l

measurements.

A riens Rappers examined 53 fo e ta l pelves

and could fin d no sexual fe a tu re s in any p a rt of the pre­ n a ta l p erio d .

Yamamura examined 14o fo etu ses in Kyoto.

He does not b eliev e in the p re n atal d iffe re n c e s in the female p e lv is .

Morton could find few sexual d iffe re n c e s

in th e f o e ta l p e lv is .

This disagreem ent of l a t e r obser­

vers w ith e a r l i e r opinion seems to re-open th e q uestion of sex d iffe re n c e s in th e fo e ta l p e l v i s .n According to Havelock B ills (9), "The p e lv is conw titu te s the most undeniable, conspicuous and unchangeable of a l l th e bony human secondary sexual c h a ra c te r s ."

He

adds a ls o , th a t i t is a t once th e proof of high ev o lu tio n and the promise of capable m a te rn ity .

Hunter was the

f i r s t in v e s tig a to r to p o in t out th e se sexual v a r ia tio n s . Race, c o n s titu tio n , environment, hormones, n u tr itio n and occupation are some o f th e main fa c to rs which are said to in flu en ce the shape or the p e lv is .

An enquiry in to

the c h a r a c te r is tic fe a tu re s and d iffe re n c e s in the sexes o f a number of pelves obtained from a homogeneous so c ie ty may e lu c id a te some f a c ts regarding th e in h e rite d fa c to rs and sexual v a r ia tio n s in t h is p a r tic u la r group.

4

MATERIAL AND METHOD, Seventy specimens of f o e ta l pelves were obtained.

The

la rg e r number were c o lle c te d in the post-mortem room o f the M aternity H o sp ita l, Glasgow, w ith th e kind peim ission of th e P a th o lo g is t, Dr. Govan.

The pelves were removed en­

t i r e between the f i r t h lumbar v erte b ra (upper borderj and the two hip jo in ts on e ith e r s id e .

These belonged to bodies

o f new-born in fa n ts which were e ith e r s t i ll - b o r n o r had died a few days (under one week) a f t e r b i r t h .

A few younger

fo etu ses were obtained from th e fiabryology c o lle c tio n of the lo c a l Anatomy departm ent.

These were made a v a ila b le

by the kind peim ission o f Dr. B acsich, o f the Anatomy de­ partm ent. As soon as th e specimens were receiv ed , th e X-ray photographs were tak en .

F orthw ith the specimens were

deposited in 90 p er cent alo o h o l.

Each of th ese specimens

was then d is s e c te d to observe th e p e rito n e a l r e f le c tio n , the n ature o f attachm ent of th e p elv ic fa sc ia and the d is ­ p o s itio n o f the v is c e ra .

A fte r removing the s o ft p a rts

they were put in to 1 p er oent hydrochloric acid fo r 24-48 hours;

th en they were again cleaned and put in to 90 per

oent a lc o h o l.

L a te r they were cleaned w ith ch lo rid e o f

lim e, tr e a te d w ith 30 p er cent hydrogen peroxide, and again put in to 90 p er cent a lc o h o l. The pelves belong to d if f e r e n t age perio d s.

Hence

the C.R. len g th or each specimen was taken and the age period determined by th a t fa c to r as w ell as by o th e r gen­ e r a l c h a ra c te r is tic s *

In each case the sex was noted*

Measurements, in d ic e s, and o th e r o b se rra tlo n s haye been made to a sse ss the Talues of each p e lv is according to the sev eral fa c to rs in d icated in the Yarious c la s s if ic a tio n s la id down by Caldwell and Moloy*

Measurements hare been

taken by th e aid or a c cu rate d iv id e rs , c a lip e r s and c e n ti­ m eter scale*

The p o in ts selected to measure th e p a r t i ­

c u la r d ista n c e s correspond to the d e s c rip tio n o f the p a r t i ­ c u la r diam eters in standard textbooks*

A few methods,

however, were adopted to o b tain o e r ta in measurements* These a re given below* 1* The area o f each p elv is a t th e p elv ic brim was ob­ tain ed th u s sThe p e lv is was kept in sid e an epidiascope w ith the i n le t facin g upwards.

The area of the p e lv ic brim was

marked out on th e screen*

Next th e specimen was removed

and a graph paper in m illim e te r squares was re fle c te d on the screen over the f i r s t diagram*

The area was counted

out in square m illim e te rs and the diagram of the p elv ic brim removed.

The m ag n ificatio n on th e screen was kept

a t a oonstant le v e l by th e uniform d ista n c e of the e p id ia ­ scope from th e screen in each case*

Also the m agnifica­

tio n was read o f f as fo u r tim es the objeot in sid e th e

epidiascope by reading o f f th e graph paper by means of a cen tim eter sca le on th e screen*

By t h i s method the square

areas of each o f the pelxes was read o ff and calcu lated * 3* Measuring th e sub-pubic an g le* In diagram Ho*

i s shown an open cardboard box

placed upside down w ith two side fla p s which are fix ed to the ta b le by fa s te n e rs .

On the top o f the box a re c ta n ­

g u la r opening, ABCD, i s made*

Oxer the middle of th e

lin e AB, a t the point E which i s ju s t aboxe the fre e margin, a small p in w ith a b ra ss top i s fixed round which a loop o f tw ine, FG, i s passed*

One limb of the tw ine FG i s fix ed

o re r th e margin CD w ith an o th er pin4 The p oint of th e pubic arch of th e fo e ta l p elT is was placed a b u ttin g from underneath the po in t E*

The in n er

margin of the sid e of th e pubic arch was ad ju sted along the fixed limb EG.

The fre e limb o f the tw ine was moxed

to the opposite margin of the pubic arch and fixed tem p o rarily on the margin CD say by a p o in t H*

Angle EEG gare the

measurement o f the pubio angle* SCOPE OF INVESTIGATION* The specimens under o b serv atio n a re a mixed s e r ie s of f o e ta l pelxes belonging to both sexes and to d if f e r e n t age p erio d s from fo u r months upwards.

Hence an attem pt has

been made to study the growth of the p e lv is in it a various stag es of development, re g a rd le ss o f sex as w ell as in r e la tio n to sex c h a ra c te ris tic s * O bservations have been made aocording to th e c l a s s i ­ fic a tio n s la id down by Caldw ell and Moloy, a f t e r d iv id in g the pelves in to various groups* In an a r t i c l e w ritte n by Howard Moloy (10) on th e p elv ic model m anikins in Columbia U n iv e rsity , which are b u ild on the s k e le ta l specimens c o lle c te d by the l a t e Dr* Wingate, Todd Western Reserve U n iv e rsity , C leveland, and now a v a ila b le to th e Anatomy department of the same U niver­ s i ty , the au th o r reviews th e recen t c la s s i f i c a tio n s o f the female p e lv is as published o r ig in a lly in Gynecology and O b ste tric s (e d ite d by C arl Henry David, M.D., W.F. P r io r Co*, Inc*, Hagerstown, Md. T*

See C hapter 3: 15; p p .82-83).

The same c l a s s if ic a tio n is reproduced below.

The types

caused by d is e a s e , trauma and a ffe c tio n s o f th e spine and femur, have been omitted* Nonaal female growth types* 1. 2. 3* 4* 5. 6. 7. 8* 9• 10.

V ariatio n s a t the i n l e t *

True anthropoid ty p e. Anthropoid gynecoid ty p e. Anthropoid android* True gynecoid. Gynecoid an th ro p o id . Gynecoid android. Gynecoid f l a t . True and ro id . Andro id a nt hropo id • Android gynecoid.

9.

PlI.VK

I n i .M

in

W

\ \ I iK( ill)

11. Android f l a t . 12 . True p la ty p e llo id . 13. F la t gynecoid. 14. F la t android. V ariatio n s below th e i n l e t , 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12.

Side w a lls of th e pelY is: d iv erg e n t, s t r a ig h t , convergent. Sub-pubic angle: wide, m oderate, narrow. Pubic Bami: s tr a ig h t (Gothic - m ale). Pubic Symphysis: m asculine o r fem inine ty p e. I s c h ia l Spine: long, sharp, short or f l a t . Apex o f Saoro: s c ia tic notch - wide, narrow o r average• Base o f S a c ro -s c ia tic notch: w ide, average, narrow Number o f s a c ra l segments. S a c ra l C urvature (a) lo n g itu d in a l, s t r a i g h t, aver­ age, marked. (b) Lower p o rtio n : forward average - o r backward. S a c ra l In c lin a tio n : (a) upper p o rtio n : forward average backward. (b) Lower p o rtio n : forward average or backward. Terminal Sacrum: sharp, average o r b lu n t. L a te ra l Bore: d iv e rg e n t, s t r a i g h t , convergent.

General P elv io V a ria tio n s . 1. P elv ic s iz e : (a) la rg e , average, sm all. (b) pelvim etry measurements of c a rd in a l d iam eters. 2 . Symmetry or th e p e lv is : (a) symmetrical a t th e in le t o r lower p e lv is . (b) asym m etrical a t the i n l e t , mid o r lower p e lv is 3. P elv ic bones: heavy, average or l i g h t . From a survey of th e se c l a s s if i c a tio n s c e r ta in c le a r cut problems a r is e as reg ard s th e v ario u s stag es o f develop­ ment. 1.

The p o s te rio r segment o f each p e lv is forms th e mos

v alu ab le c r i t e r i o n in the c l a s s i f i c a ti o n of th e four c la s s ­ ic a l i n l e t s of th e female p e lv is , v iz . the gynecoid, the

android, th e anthropoid and th e p la ty p o llo id .

I s t h i s an

in h e rite d fa c to r induced by sex hormones, enzymes or o th e r organising chemical agents? 2. The a n te r io r segment also is an im portant c h a ra c te r­ i s t i c of each m ajor c la s s of p e lv is .

I s t h i s a f a c to r in ­

h e rite d during in tr a u te r in e l i f e o r acquired during the p o s tn a ta l, childhood and adolescent periods? 3 . The l a t e r a l bore of th e p e lv is as judged by th e base and apex o f the s a c ro s c ia tic notches i s found to possess fe a tu re s id e n tic a l w ith th e d e s c rip tio n of the p e lv is . Are th ese fe a tu re s a lso p re se n t a t b irth ? 4. The c a p a c ity of the c a v ity o f the p e lv is is d e te r­ mined by the depth of th e symphysis, the curvature of the sacrum, and th e slope o f th e sid e w a lls .

Are th ese fe a tu re s

tra c e a b le a t b i r t h as d if f e r e n t in th e sexes? 5. The mid plane o f th e p e lv is , passing through the in ­ f e r io r border of th e symphysis, the is c h ia l s p in e s, and th e diso between th e th ir d and fo u rth sa c ra l v e rte b ra e , i s of g re a t c l i n i c a l importance in th e a d u lt female p e lv is .

The

bu ild o f th e symphysis, the cu rv atu re of th e sacrum and the n atu re of the i s c h ia l spines w ill a f f e c t th e p lan e.

How f a r

is th e f o e ta l period re sp o n sib le f o r the fe a tu re s o f t h i s plane? 6. The o u tle t of th e p e lv is i s assessed by the in te r tu b e ra l diam eter, sub-pubic an g le, and th e a n te ro -p o s te rio r

diam eter.

Do th ese fe a tu re s p resen t any s ig n ific a n t sexual

c h a r a c te r is tic s a t b irth ? 7. T urner’ s c l a s s i f i c a ti o n o f the i n l e t o f the p e lv is as form ulated by th e p elv ic brim index i s o f sig n ific a n c e from an eth n o lo g ic a l sta n d p o in t.

I s t h i s r a c ia l fe a tu re

presen t a t b irth ? 8 . The g en eral assessm ent of th e p e lv is by the h e ig h tbreadth index i s o f an th ro p o lo g ical i n t e r e s t .

I s t h is an

in h e rite d fe a tu re which can be demonstrated a t b irth ? The above q u estio n n aire forms the b a s is upon which the work has been c a rrie d out on th e sev eral f o e ta l p elv es. OBSERVATIONS. S ix ty -fo u r specimens out of th e seventy have been c la s s if ie d in to groups according to the m orphological shapes o f the p o s te rio r segments of th e i n le ts of th e p elv es.

The

four o la s s ic a l d iv isio n s of th e i n le ts of th e p elv es, accord ing to the shapes of th e p o s te rio r segments, a re shown on the opposite page. The follow ing i s a ta b le showing the c l a s s i f i c a ti o n o f th e fo e ta l pelves o f both sexes in to th e fo u r main d iv is io n s :

S e ria l No* o f Male P e lv is Gynecoid Android

S e r ia l No«of Female j P e lv is [ T otal

4 6 ,6 7 ,4 8 ,5 3 ,5 1 ,5 5 ,60

3 ,8 ,1 8 ,2 8 ,7 0 ,3 0 ,3 1 ,! 33,42*57^66! j | 1 ,3 6 ,4 0 ,6 1 ,5 ,3 5 ,4 3 ,3 8 , 4 7 ,4 1 ,4 9 ,6 4 ,6 5 . 1 3 9 ,4 5 ,5 0 ,5 6 ,5 8 ,6 2 ,6 8 , 1! 69,63.

18 22

i

N il P laty p ello id N il 1 Anthropoid 2 ,1 2 ,2 3 ,2 5 ,9 ,1 0 ,1 5 ,1 6 , 1 1 ,1 3 ,1 4 ,1 7 ,2 9 ,3 2 , 2 6 ,3 7 ,2 7 ,5 4 ,5 9 . 34,4 4 ,1 9 ,2 0 ,5 2 . T otal , „. —

_____

■■

t; i j J 1 1 1

24 64

From the abore ta b le the percentage v alues o f each c l a s s i f i c a ti o n belonging to the d if f e r e n t sexes were a s e e rta in e d .

I t works out as follow s:

I ! Gynecoid i 18*9 Male | i 40.7 Female j i

Android 45.9 18.5

Anthropoid ] P la ty p e llo id I 1 ---35.2 1 40.8 —

1

100 100

4----------------------------------------- —

The se v e ra l values o f th e t o t a l as w ell as th e v ario u s fa c to rs of the t o t a l s tru c tu re of th e pelves were determined by the ap p ro p riate in d ic e s, measurements and observations* An attem pt has been made to a sse ss th e v alues o f th e nine to te n months* period p e lv is , i*e* above 300 mm* C«R#le n g th , according to th e sexes, w ith a p a r tic u la r enquiry in to the gynecoid type of p e lv is which i s the type n e a re st th e ob­ s t e t r i c id e a l.

E valu ation o f th e T otal S tru ctu re o f th e -Pelves*

O bservations on th e t o t a l s tru c tu re of th e pelves were made by an enquiry in to th e b re ad th -h eig h t index, th e depth height and th e i l i a c w id th -h eig h t index o f each pelvis* The b read th -h eig h t index of the d if f e r e n t groups o f p elv es: Male: Female: Gynecoid Female:

80.67 85.05 82.96

(av erag e). (av erag e). (av erag e).

Thus th e h eig h t o f th e female fo e ta l p e lv is is found to be g re a te r than th a t o f th e fo e ta l male p e lv is .

T h is t a l l i e s

w ith th e o b serv atio n s made by S ir A. Thomson (11) whose fin d in g s are re c a p itu la te d below: The b read th -h eig h t index:

85*6 in th e fem ale (av erag e). 82*4 in the male (average)*

In h is a r t i o l e on th e sexual d iffe re n c e s o f th e fo e ta l p elv es, S ir A rthur Thomson observes th a t th e height of the female p e lv is i s in p ro p o rtio n to i t s w idth.

He a lso says

th e b read th -h eig h t index of th e female is g r e a te r than the m ale.

In th e a d u lt i t is g r e a te r in the male th an the

fem ale,

so during growth the bread th o f the p e lv is i s con­

s ta n tly increasing* The depth-height index was c a lc u la te d and th e percen­ tag es worked out fo r th e two sexes a s w ell as the gynecoid type o f female p e lv is . Male: Female: Gynecoid Female:

The r e s u lt s were as follow s: 44*6 45.38 46*36

(av erag e). (av erag e). (a v erag e).

The r e s u lts do not show a p a ra lle lis m w ith the values of th e ad u lt p elv es, where one of the c h a r a c te r is tic fe a tu re s of the female p e lv is is th e shallow ness o f th e tru e p e lv is . The fa n ale s e rie s possess a com paratively g r e a te r depthh eig h t r a ti o th an th e m ale. The average w idth or the i l ia c c r e s t of the female p e lv is is 4.19 oms. and of th e male average fo r fu li-te z m p elv es 4.25 cms.

The percentage value of the ilia c -w id th -

height index works out to 69.75 th e m ale.

in the female and 70.03 in

S ir A rthur Thompson (12) obtained an average

measurement or 42 mm. in the male and 41.1 mm. in th e fem ale, fo r th e width o f th e i l i a c c r e s t in th e fo e tu se s examined by him.

The i l i a c w idth-height in d ic e s in t h i s

s e r ie s do not in d ic a te any sexual fe a tu re . The P elvic I n l e t . The p elvic i n le t foxms an e s s e n tia l fa c to r in the c l a s s i f i c a ti o n la id down by Caldwell and Moloy (1 3 ).

The

i n le t i s divided in to two main segments by th e g re a te s t tra n sv e rse diam eter of th e i n l e t .

The main c la s s i f i c a tio n

o f the p resen t s e rie s has been based on th e m orphological shape o f th e p o s te rio r segment o f th e p elv es.

The f u r th e r

d e s c rip tio n o r th e i n l e t o f th e p e lv is i s in d icated by th e shape of the a n te r io r segment of the p e lv is which is a lso described as gynecoid, an d ro id , anthropoid and p la ty p e llo id . The a n te r io r segments of the p re se n t s e rie s have been

examined and the percentage number of the c la s s ic a l shapes to the male, female and the gynecoid female groups ta b u la te d The ta b le or c l a s s i f i c a ti o n is given below: I

1

| Male i Female ] Gynecoid i

j i j i

? i I Gynecoid ! Android ! Anthropoid ! F la ty p e llo id r I j

51.3 2.6 35.1 55.5 | 44.5 27.2 72.8 | ■■■...... -■ ■1-------------------- ----- ------ ---------

10.8 -

I t is in te re s tin g to observe th a t th e android type of a n te r io r segments was seen in only one male type o f p e lv is . Most or the pelves possess a n te r io r segments which are e ith e r gynecoid o r anthropoid in shape.

This fe a tu re of

the a n te r io r segments is seen even in a cursory view o f the pelves during d is s e c tio n . Turner* s c l a s s i f i c a ti o n (14) o f the p elv ic i n l e t has not been replaced by th e p resen t c l a s s i f i c a ti o n as f a r as the an th ro p o lo g ical o b serv atio ns a re concerned,

tfo the

p e lv ic brim in d ic e s were c a lc u la te d in each o f th e fu li-tex m pelves and the t o t a l number was divided in to th e several groups, as follow s: D o lich o p ellic Male Female Gynecoid Female

43.2 51.8 63.6

i M e sa tip e llic ! P la ty p e llio ; 8.1 ! 48.7 22.2 | 26.1 9.2 j 27.2

D o lich o p ellic is considered as the type w ith a p elv ic

i i | | 1

brim index or over 95 p e r c e n t;

m e s a tip e llic as possessing

an index between 90 and 95 p er c e n t; and the p la ty p e llic as possessing an index under 90 p er c e n t. The d o lic h o p e llic type seems to be th e preponderant type in th e t o t a l s e r ie s .

This a lso p o in ts to the fa c t

th a t th e a n te ro p o s te rio r diam eter of th e i n l e t i s longer than th e tra n s v e rs e in many specimens.

The comparative in ­

crease in the breadth of th e p e lv is occurs only a f t e r the b i r th of the c h ild . m

The p la ty p e llic i n l e t s observed in th e male group can

be accounted fo r by th e fa c t th a t many o f the male pelves possess th e a n d ro id -p o s te rio r segment w ith a sh o rt p o s te rio r s a g i t t a l diam eter and a rounded a n te r io r segment.

In th e

a d u lt type o f p e lv is th e w h ite and yellow ra ces are endowed w ith the p la ty p e llic type of i n l e t , th e d ark er a b o rig in a l races being said to possess th e d o lic h o p e llic ty p e, and th e negroid ra ces a m e s a tip e llic type of p e lv ic i n l e t .

i,

The p elv ic brim area was c a lc u la te d in each p e lv is . The percentage values of each pelvic group are given below:

Area o f P elv ic Brim

I | 1 j j

Male 7

03 sq.cm s. H

Female

j Gynecoid Female . .. — ' t...... 1 7.33 sq.cm s. j 7.32 sq.cms. 1

Percentage values were a lso c a lc u la te d to discover th e r e la tiv e p ro p o rtio n of th e w idth of the sacrum and in t e r -

c r i s t a l w idth or the p e lv is as w ell as the r a ti o between the tra n sv e rse diam eter of the pelv ic brim and the i n te r c r i s t a l b read th . --------------------------------------------------i

| !

S acral WidthI n t e r c r i s t a l B readth Index.

T ransverse Diameter Br i a - I nt ere r i s t a 1 B readth.

42.35

45.94

42.37

46.76

i

Male

|

I

Female ! I

The above ta b le shows a s lig h t in cre ase in the width o f the sacrum but a g r e a te r in cre ase in the tra n sv e rse diam eter a t th e brim in th e female specimens as compared w ith t h e i r i n t e r c r i s t a l w id th .

These v alu es a re of sig n i­

fica n ce because in the a d u lt female th e r e la tio n s are s im ila r. The average v alu es of th e s a c ra l w idth and tran sv e rse diam eter a t th e brim a re given below: i 1 1 I i

In te rc ris ta l Width

Average S acral Width in S peci­ mens above C.R.L. 300 mm.

Average T ransverse Diameter Brim in Specimens above 300 mm. C .R.

! Male

7.5

cms.

3.24 cms.

3 .4 cms.

1 Female l........................

7.17 cms.

3.04 cms.

3.36 cms.

j

I t i s now c le a r th a t i t is the g r e a te r width of the i n t e r c r i s t a l d is ta n c e in th e male which produces th e le s s e r value o f the index between th e s a c ra l width and the in te r -

o r i s t a l diameter*

So between v alu es o f s a c ra l w idth,

tra n sv e rse diam eter and i n t e r c r i s t a l w idth, i t i s the d is ­ tance between th e c r e s ts o f the ilium which is s i g n i f i ­ c a n tly h ig h er in th e male as compared w ith the female* The L a te ra l Bore of th e P e lv is ( f o e t a l ) • The follow ing ta b u la tio n shows th e measurements and observ atio n s made on the se v e ra l fe a tu re s of th e l a t e r a l bore in both sexes* 11 ' ■' Measurement o f the base of the l e f t S. I! Sex S. Notch* ........ Male ■ Female _ ___

1*45

APEX OF SACROSCIATIC NOTCH: Wide | Moderate Narrow i ! 54.5% 45.9% i

7.1% ! 69.3% _______ 1___________

87.6% 1

The female specimens do not show a broader measurement of the base in th e s e r ie s ;

however, the apex shows a g re a te r

number of moderate curves over the ap ices of th e g re a te r s c ia tic notch. The C avity o f th e f o e ta l P e lv is , An attem pt was made to measure th e v e r tic a l le n g th o f the sacrum, the height o f th e symphysis, and a lso to des­ c rib e the n atu re o f th e is c h ia l spines and th e splay o f the sid e walls*

These fa c to rs c o n s titu te th e sev e ral fe a tu re s

which go to form th e p elv ic cavity*

Photograph o f specimen No.5. Male P lv . To note o o n fig u ra tio n and i n l e t .

L

Photograph o f Specimen No.57. Note c o n fig u ra tio n and in le t.

--------------------------------------- — ------------------------------------------------------- -----------------------------------------—



Photograph Specimen No.17 (en larg ed ) to show subpublc an g le.

18.

!

1

I 1 1 ............

1 I 1

! 1 i Male ! | Female j i Gynecoidj ! Female j

V e rtic a l Height o f Sacrum cms. 3.2 3.09 3.2

■ 1 .............. " “ j Height of Symphysis ! cms. 1 .3 1.14 1.12

! ! I -

| NATURE OF ISCHIAL SHINES: ! Blunt Moderate I Sharp or Average! .1if i 45.5# !55.5# Male • 59.2% | 40.8% Female j Gynecoid i 80.0% j80.0% Female !

-

j SPLA*!r o r SIDS WALLS: ?Diverg- Converg-' S tra ig h t | ing ing ! I 85.7% i 14.3% ! ' | 3.9% 46.1% i 50.0% 60.0% | 40.0% | -

In th e abore observ atio n s i t can be seen th a t th e height o f the sacrum in th e female s e r ie s is 0.12 cms. le s s than in th e m ale.

The gynecoid type o f th e female pelves

do not show a lower v alu e.

The height o f the symphysis

c le a r ly in d ic a te s a lower value fo r th e female which is in accordance w ith the le s s e r height of the symphysis in the a d u lt. The n atu re o f the is c h ia l spines i s more o f th e aver­ age type in the female and th e sh arp er type more p rev alen t in the male.

The anthropoid ty p e w ith th e b lu n t is c h ia l

spine is a b se n t. The sp la y or the sid e w a lls is s ig n if ic a n t in the male s e rie s where th e re is a g r e a te r percentage of the converg­ ing ty p e.

The female specimens show a small percentage

of th e d iv erg in g types and almost equal numbers of the

converging and s tr a ig h t ty p e s. The plane or th e m id-cavity o r the p e lv is passes through th e in f e r io r margin o f the symphysis pubis, the is c h ia l sp in es and th e p o in t between th e fo u rth and f i f t h s a c ra l v e rte b ra e .

Hence the in te ris c h io s p in a l diam eters

are measured in each s e r ie s and shown below:

]_______________________

In te r is c h io s p in a l Diam eter.______ ij

l

I |

Male Female Gynecoid

I j |

I_______________________________ i_______

2.23 2.27 2.34

] j i

______________________________________1

The fig u re s i l l u s t r a t e th e tendency to widening o f the in te ris o h io s p in a l diam eter in the female s e r ie s and an even g re a te r tendency in th e gynecoid s e r ie s . The O u tlet of th e P e lv is in the F o etu s. In th is p a rt o f th e work th e sub-pubic an g les, the n atu re o f the pubic arch and the len g th o f the in te rtu b e rous diam eter were a sse sse d .

] Male i Female jGynecoid

!...................... ” Sub-pubic i PUBIC AKCH: * VALUES: j In te rtu b e ra 1 •Angle ! Wide Moderate iNarrow ! Diameter i f 22.2* | 61.1* j 1.7 cms. 1.6.7* 55.9° 25.9* 29.6* ( 44.5* | 1.94 cms. 62.4° 21. cms. 66.6* ! 16.6* 16.8* 65.50 |

The readings are s ig n if ic a n t, y ield in g in the female a h ig h er fu n o tio n of th e pubic an g le, a higher p ro p o rtio n o f

l j I 1 J I {

Re k A

G Jf • B

2

1 F e m a le C he

A r tic u la r b a tt« rn $

/7Za/«

o f th e l/a te r a l

S u r fa c e ^ of

t h e . S a c r a w k e t e th e V e r t i c a l U i m h f r e a c h

th in ) o c r t i b t a in

b o th

js e x e $ .

to

th e

moderate and wide ty p e o f pubic arch es, and a c le a r in ­ crease in the in te r tu b e ra l d iam eter. The S a c ro -ilia c A rtic u la tio n , The l e f t s a c r o - ilia c jo in ts were d is a r tic u la te d in each p e lv is , a f t e r a l l th e c la s s ic a l measurements were tak en . In th e full-grow n fo etu ses th e ligam ents are q u ite strong and w ell-developed. In a l l specimens th e h o rizo n tal limb o f th e L-shaped a r ti c u l a r su rface over th e upper a n te r io r p a rt o f th e l a t e r a l surface o f the sacrum was placed over the upper p a rt of the f i r s t s a c ra l p ie c e .

The v e r tic a l limb showed v a r ia tio n s .

Only six out or th e 27 female specimens showed th e v e r tic a l limb lim ite d to the f i r s t two upper segments o f th e sacrum. In te n o f th e specimens th e v e r tic a l limbs descended to almost th e middle of the th ird segment, and in th e r e s t of the specimens th e v e r tic a l p a rt of th e a r t i c u l a r fa c e ts descended almost as f a r as th e lower border of th e th ir d s a c ra l segment.

In th ese cases th e lower p a rt of the v e r t i ­

c a l lim bs were comma-shaped, as shown in th e fig u re . In the male s e r ie s th e re i s not one specimen where the v e r tic a l limb i s lim ite d to th e upper two segments. o f them descend c le a rly to

Most

th e lower border of th e th ir d

and a few extend to between 2 j and 3 s a c ra l v e r te b ra e . So the sex fe a tu re o f the s a c r o - ilia c jo in t seems to be not a constant one, as f a r as th e a r t i c u l a r component o f

the sacrum i s concerned.

However, the higher evolutionary

fe a tu re which is more pronounced in the breadth and sh o rte r len g th o f the sacrum, is a ls o ex h ib ited in the a r t i c u l a r surface in th a t only th e female sacrum possesses the a r t i ­ c u la r component lim ite d to the upper two segments of th e bone.

However th is fe a tu re is seen only in a few of the

female s a c ra .

So even here the sexual v a r ia tio n i s marked

in only a few in d iv id u a ls .

The longer v e r tic a l a r ti c u l a r

surface over th e female sacrum i s a d e f in ite impediment to i t s m o b ility , an e s s e n tia l requirem ent in c h ild -b e a rin g . In th o se specimens where the s a c ra l a r t i c u l a r su rface descended to more than the second segment, the lower end was hooked o f f lik e a comma p o s te r io r ly .

Thus the a r ti c u l a r

su rface on the th ir d sa c ra l segment i s much narrowed and r e s t r ic te d to i t s p o s te rio r p a r t. The 22.2 per cent of female sacra (6 out o f 27) w ith the v e r tic a l p a rt of th e a r t i c u l a r su rfa ce lim ite d to the upper two p ieces compares favourably w ith the 20 p e r cent data observed by C.P.Y. Smout (15) and recorded in h is des­ c r ip tio n of th e sacrum in h is book on th e gynaecological anatomy o f the p e lv is . The d ista n c e between th e symphysis pubis and th e a c e ta ­ bulum does not show any sexual fe a tu re in the female as pronounced as in th e a d u lt.

I t i s probable th a t t h i s

fe a tu re is developed in the p re p u b ertal stag es w ith th e

attainm ent o f th e g en er a l breadth o f th e p e l v i s .

OBSERVATIONS ON THE DIFFERENT SERIES IN THE VARIOUS GROWTH PERIODS. One im portant fa c t emerging from t h is work i s the h ig h er r a ti o o r height to breadth in th e specimens under 200 mm. crown rump le n g th . The follow ing ta b le shows th e values: 1 1

1 I

1

!

!

'' j Male j Female i

" 1! j I j

i

HEIOHT-BREADTH INDEX: C.R. Length | C.R.Length | C.R.Length under 200 i under 300 i over 300 ! mm. mm. j mm. 1 86.36 j 85.1 | 80.66 -

j

1

90.57

85.05 __ 1______________ j

In the e a r l i e r stag es th e p e lv is f i r s t a tta in s a c e r­ t a in p ro p o rtio n o f th e h eig h t p e rta in in g to the human sp ecies. The b read th develops only g ra d u a lly in the l a t e r sta g e s. The h ig h er b re ad th -h eig h t r a t i o of th e female i s even h ig h er in the 200-300 mm. s ta g e s . e stin g stu d y .

The p elv ic index is a ls o an i n t e r ­

The a n te ro p o s te rio r len g th or the brim i s

the most marked fe a tu re in th e younger specimens as shown below. P elv ic Index Table ---------------- rUnder 200 mm. { Orer 200 mm. I Under 100 mm. C.R.L. C.R.L. ! C.R.L. ----------1 97.47 | 87.06 Male ] 101.9 97.83 j 96.90 female 1

As th e dimensions of th e p e lv is are la id down in the e a r l i e r stag es of fo e ta l growth, i t i s the h eig h t and the a n te ro p o s te rio r diam eters which are f i r s t determ ined.

The

upper ex trem ity , whioh has a g re a te r su rv iv a l value over th e lower, i s b e tte r developed a t b i r t h .

The lower ex­

trem ity w ith i t s g ir d le i s recognised a s com paratively le s s w ell developed.

I t is only as the c h ild begins to walk

th a t the lower e x tre m itie s a s s e rt t h e i r importance and com­ mence t h e i r advancing degree o f development.

The in te g r ity

o f the p e lv ic g ir d le has to keep pace w ith the in cre asin g fu n c tio n a l a c t i v i t y of th e lower e x tre m itie s and^ th e pro­ p o rtio n a l bread th o f the p e lv is is l i k e l y to in cre ase in th ese stag es as w ell as in the p re p u b e rta l p erio d . A few skiagrams a re attach ed to show the v a r ia tio n s between th e male and female fo e ta l p e lv is . I.

No.5 i s a f u ll- te im male ty p e .

The general converg­

ing type of th e a r c h ite c tu re is w ell-m arked.

The narrow

apex of th e g re a te r s c i a t i c notch i s very c le a r . No.46 i s a younger male specimen, 210. a c t e r i s t i e s are n o tic e a b le even in t h i s .

The male ohar^V c

I I . No.42 is a gynecoid ty p e of female specimen.

This

specimen shows a d e f in ite d iv erg en t to s tr a ig h t type o f a rc h ite c tu re and the broad apex o f th e g re a te r s c ia tic notch is c le a r . No.8 i s a younger female specimen also showing female fe a tu re s .

. '

Specimen N o.5 Male P e l v i s . F u l l - t e i m . convergence of Lower P e l v i s .

To n o te

Specimen No.42. Fediailie P e l v i s . F u l l - t e r m . d iv e rg e n c e o f Lower P e l v i s .

To n o te

An e a r l i e r Specimen o f t h e Male P e l v i s . Specimen No.46, 210 mm. C.R.L. To n o te co n v erg in g elem ents o f low er P e l v i s .

An e a r l i e r Specimen of th e Female P e l v i s . Specimen No.3, 2 5 0 mm. C . R . l . To n o te d iv e r g in g elem en ts o f lo w er P e l v i s .

CONCLUSION. The exam ination of t h i s s e rie s o f fo e ta l p elves r e ­ veals the fa c t th a t th e re a re d e f in ite v a r ia tio n s which occur in th e g en eral shape, c o n fig u ra tio n and c l a s s i c a l measurements as w ell as in the recognised index values or these v ario u s specimens. These d e f in ite v a r ia tio n s confoim to the d e s c rip tio n s la id down by Caldwell and Moloy (16) in t h e i r c la s s ic a l d iv is io n s o f th e female p e lv is .

The p o s te rio r segments o f

the i n l e t lying behind th e g re a te s t tra n sv e rse diam eter show the d if f e r e n t shapes conforming to the tenns Gynecoid, Android, and A nthropoid.

There was no ty p ic a l p la ty p e llo id

segment seen in th is s e r i e s .

A ll th e female specimens do

not possess the gynecoid p o s te rio r segment.

However 40*7

per cent o f the female p elv es possess the gynecoid p o s te rio r segment and hence a re c la s s if ie d as th e gynecoid ty p es of p e lv is .

This percentage agrees w ith 41.5 p er cent of

gynecoid type of p e lv is found among a d u lt American w hite women;

so the p o s te rio r segment does appear as th e in ­

h e rite d f a c to r . The expression o f th e female sex v a ria tio n s i s more gynaecoid c le a r ly marked in the specimens possessing th e /p o s te r io r segment.

Of the six female pelves in the t o t a l s e r ie s o f

64 which possess the v e r ti c a l component o f the s a c ra l a r t i ­ c u la r su rfa ce lim ite d to th e upper two segm ents, th re e

belong to th e gynecoid type o f female p elv es. I t i s an in te re s tin g fe a tu re th a t th e re is an i n t e r ­ m ingling o f the sexual fe a tu re s in th e se v e ra l p e lv e s. This observ atio n may very w ell be augmented by the remarks made by u reu lech and Thoms (17) who s ta te th u s:

"Our fin d in g s

in d ic a te th a t the p e lv ic in le t o f th e male is as v a ria b le in shape as th a t of th e fem ale.

I t i s evident th e re fo re

th a t in our type o r p o p u latio n th e re is no one type o f male o r female p e lv is ." The b read th -h eig h t in d ic e s of th e pelves in th e two sexes c le a r ly p o in t to th e fa o t th a t th e female p e lv is a tta in s a g re a te r p ro p o rtio n o f th e h eig h t as compared w ith i t s breadth in i t s f o e ta l sta g e s.

During th e p re p u b e rta l

stages i t s growth is concentrated on i t s breadthw ise dimen­ sio n s, so th a t th e b read th -h eig h t index in th e female is le s s in th e a d u lt than in th e male. i t i s seen th a t th e depth of th e fo e ta l p e lv is in comparison w ith i t s h eig h t i s g r e a te r in the female than in the m ale.

The h ig h er depth-height index (45.3) in th e

female aw compared w ith the male (44.6) s ig n if ie s a higher depth o f th e tru e p e lv is in th e female in th e f o e ta l sta g e , nowever the average depth o f th e female fo e ta l p e lv is is 2.75 cm s., and in th e male i t is 2.85 cms.

Schuman ob­

ta in e d the values o f 90 mm. in th e female and 101 mm. in th e male by measuring th e pubotuberous diam eters in the a d u lt. (1 8 ).

The slen d er a n te r io r segment or th e p e lv ic in le t is e it h e r oval or rounded in th e main during th e fo e ta l sta g e s, and the sexual fe a tu re i s developed in th e p rep u b ertal s ta g e s .

In r ic k e ts th e a n te r io r segment of th e p e lv is

ta k e s th e g re a te r share of th e p elv ic deform ity, th e bony mass overlying th e g r e a te r s c ia tic notch forming the l a t e r a l w all of th e p o s te rio r segment being le a s t a ffe c te d .

N ichol­

son has found by s t a t i s t i c s th a t the brim of th e p e lv is is g re a tly a ffe c te d by n u tr itio n . The p elv ic i n l e t , as judged by T u rn e r's c l a s s i f i c a ti o n p re se n ts a g re a te r percentage of th e D o lich o p ellie type which is due to th e g re a te r len g th o f the a n te ro p o s te rio r diam eter over th e tra n sv e rse dimension, which does not a t t a i n i t s f u l l dimensions u n t i l a d u lt age.

However, the

p la ty p e llo id types should p o in t to a r a c i a l s ig n ific a n c e . The w hite and yellow races are said to possess th e p la ty ­ p e llo id type of p e lv is ;

th e negroid races th e m e s a tip e llic ,

and the a b o rig in a l races th e d o lic h o p e llie ty p e . The g r e a te r measurement o f the p elv ic brim area in the female is s ig n if ic a n t. In co n sidering th e v alu es obtained w ith regard to the c a v ity o f th e p e lv is th e le s s e r dimension of th e v e r tic a l len g th of th e sacrum and th e diminished value of the h e ig h t of th e symphysis in th e female a re worthy o f obser­ v a tio n .

Thea p ice s of the g re a te r s c ia tic notches are

w ider in the female than in th e m ale. The h ig h er average v alu es of th e isch io tu b ero u s d ia ­ m eter in th e female specimens as w ell as the increased fu n ctio n of th e pubic angles in d ic a te a developm ental fe a ­ tu re o f the o u tle t of th e fe n a le type o r p e lv is in the fo e ta l sta g e .

The in te ris o h io s p in a l diam eter also shows

a s lig h tly h ig h er value in th e female than in th e m ale. Hence th e o u tle t o f th e p e lv is in the female is phylo­ g en etic a l l y f u r th e r removed from the narrower male ty p e . The v e r tic a l length or th e saorum is d e f in ite ly s h o rte r in the female.

The s h o rte r v e r tic a l limb of the s a c ra l

a r ti c u l a r s u rfa c e , being lim ite d to th e upper two s a c ra l segments, is a ls o another fe a tu re emphasising th e h ig h er evolution^of th e sk eleto n in th e fem ale.

However i t is

not a constant fe a tu re in th e female. The hooked p a tte rn of the lower end of th e v e r tic a l Hurt) of the s a c ra l a r t i c u l a r su rface in th e female of sp e c i­ mens where th e a r tic u la tio n ex tends to the th ir d p iece i s s ig n ific a n t of th e in term ed iate stage towards the process or a two p iece sa c ra l a r ti c u l a t i o n . One or the marked fe a tu re s in the o b serv atio n s i s th e interm ingling o r the b isex u al fe a tu re s in the g r e a te r number of specimens.

This may be explained by th e hypothesis th a t

the sex determ ining genes o f the chromosomal complex have to ca rry on t h e i r fu n c tio n in the substance of a zygote

which is b ip o te n tia l in i t s sexual components.

Also the

in te g r ity of th e female sex p o t e n t ia l ity is much d istu rb ed by the eo rtico -m e d u lla ry antagonism o f th e ovarian hormones. These s u b tle developmental v a ria tio n s are w ell recognised by modern o b s te tr ic ia n s . Munro K err s a y s :-

"There w ill however remain examples

of minor d efo rm ities o f r a c h itic and o th e r m a ln u tritio n a l o rig in and needless to say many due to e rro rs in develop­ ment o f a g e n e tic n atu re more obscure in o r i g i n ." (19). Havelock E l l i s b e lie v e s th a t sexual d iffe re n c e s may be a ttr ib u te d to sev e ral fa c to rs , such as t r a d i t i o n , en­ vironment and th e a c tu a l c o n s titu tio n of th e male and female organism and i t is hard to say what p a rt i s played by each fa c to r, in the normal development of th e sexes. (20). A ll fa c to rs c a lc u la te d to improve th e h e a lth o f a n atio n w ith the emphasis on the b io lo g ic a l s ta tu s o f woman as th e mother of th e n a tio n , are bound to endow the fu tu re feminine race w ith a p e lv is almost s im ila r to the o b s te trio id e a l.

29

R eferences, 1.

FEHLING, Die Form dies Bee kens beim Foetus und Neutergmen.

2.

ARTHUR THOMPSON. The sexual d iffe re n c e s in th e f o e ta l p e l r i s . J.A n at. & P h y sio l. . A p ril 1899.

3.

CALDWELL and MOLOY. Anatomical v a r ia tio n s in th e female p e lv is and th e ir e f f e c t in la b o u r,w ith a suggested c l a s s i f i c a ti o n . A m er.J.O bst. & Gynaec. . 1933, p .479.

4.

HEINES. A study of the Female P e lv is . O ct. 1944.

5.

T hesis subm itted to th e Madras U n iv e rsity fo r M .Sc., P a rt I .

6.

MORTON and HEIDEN. Development o f P e lv ic C onfigur­ a tio n . Amer.J.Gyn. & O bst. . 1942, £ 7 , 145-165.

7. ARTHUR THOMPSON.

J .Anatomy.

See 2 . above.

8 . REYNOLDS, E.L. The bony g ir d le in e a rly in fan cy . Amer.J. P h y sical A nthropology. D ec.1945, 3, 321-364. 9 . HAVELOCK ELLIS.

Man and Woman.

10. HOWARD MOLOY. N.Y. Aug. 1944. 11. ARTHUR THOMPSON.

Amer.J«Obst. & Gynaec. . 48.

See 2. above.

12. I b id . 13. CALDWELL and MOLOY. 28. p.482.

Am er.J.Obst .& G ynaec.. 1934,

14.

TURNER. "R ef." A m er.J.O bst. & Gynaec. . 45, p . 950. I n te r p r e ta tio n o f ra d io lo g ic pelvim etry N icholson. Role of n u t r i t io n in p e lv ic v a r ia tio n - H. Thoms. Also 54, 1947.

15.

SMOUT, C.F.V. G ynaecological and s u rg io a l anatomy. 2nd E d itio n , p .8 .

30.

16.

CALDWELL and MOLOY. Anatomical v a ria tio n s in th e female p e lv is . Amer.J.Obst .& Gynaec. . 1933, p,479.

17.

GREULECH and THOMS. A m er.J.O bst«& Gynaec. . 1947, v o l .54, No•1• THOMS, H erb ert. Role of N u tritio n in P elvic V aria­ tio n . (New Haven).

18.

SCHUMANN. Depth of P e lv is . v o l.28.

19.

MUNRO KERR. Border lin e p e lv is . Gynaec. . 1948.

20.

HAVELOCK ELLIS.

Amer.J.Obst.& Gynaec.

Man and Woman.

B r it.J .O b s t. &

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