~ 
UNIVERSITY 
Medical Magazine. 
rZcII: 
* "L ir**0 ,r ziiiL“^c2jrE*^c»r«s!f.?i.o!*'. «t» 
|iS'|rEE,EZ:;I 
mvmtrv^E^&iiK rxrM‘ 
REPRINTED FROM 
NOVEMBER, 1894 
THE INFLUENCE OF THE HABITUAL INCLINATION OF THE 
PELVIS IN THE ERECT POSTURE UPON THE SHAPE 
AND SIZE OF THE PELVIC CANAL. 
BARTON COOKE HIRST, M.D., 
Professor of Obstetrics in the University of Pennsylvania. THE INFEUENCE OF THE HABITUAE INCEINATION OF 
THE PEEVIS IN THE ERECT POSTURE UPON 
THE SHAPE AND SIZE OF THE 
PEEVIC CANAE. 
By Barton Cookk Hirst, M.D., 
Professor of Obstetrics in the University of Pennsylvania. 
From the last quarter of the eighteenth century, when Muller first 
called attention to it, the inclination of the pelvis received much atten- 
tion from obstetricians, until the observations of Naegele, Weber, and 
Meyer showed how the pelvic obliquity varied greatly, not only in 
different postures, but even in the erect posture, under the influence 
of abduction, adduction, and rotation of the thighs. Thus, in a single 
individual, the pelvic obliquity, normally about 450, can be practically 
obliterated in a squatting posture or can be increased to ioo° by strong 
abduction and rotation of the thighs. Because the pelvic inclination 
can be decreased or increased at will, it is generally argued that the 
pelvic obliquity is a negligible quantity in the act of childbirth. 
While this view is correct, it has led to a general neglect to consider 
the influence of the habitual inclination of the pelvis in the erect pos- 
ture upon the development of the pelvic bones and upon the evolution 
of the pelvic canal. 
If there is an exaggerated inclination of the pelvis in childhood, as 
in rachitis, dislocation of the femora, double club-foot, lordosis, etc., 
the direction in which the trunk weight is received by the sacrum 
increases the rotation forward of that bone upon its transverse axis, 
diminishing the antero-posterior diameter of the inlet and diminishing 
the depth of the pelvic canal. Further, the exaggerated pull of the 
rotative muscles of the thigh, put constantly upon the stretch, separates 
the tuberosities of the ischia more widely than common, and thus 
widens the pelvic outlet. 2 
Bartofi Cooke Hirst. 
On the other hand, if the pelvic inclination is much diminished, as 
in kyphosis from caries of the spine, rachitis, or certain forms of osteo- 
malacia, the top of the sacrum is pushed backward, so that this bone 
is lengthened and straightened, thus making the antero-posterior 
diameter of the inlet greater and increasing the depth of the pelvic 
canal. Further, the pull of the ilio-psoas muscles, put upon the stretch 
in the erect posture, drags the iliac bones apart, and by a compensatory 
movement approximates the ischia, thus diminishing the transverse 
diameter of the pelvic outlet. 
The habitual inclination of the pelvis in the erect posture is there- 
fore one of the chief factors in the production of the most important 
pelvic contractions. Consequently its effect upon the progress of labor 
should not be ignored. These general propositions are well illustrated 
by the cases figured in the plate. 
Figs, i, 2, 3, and 4 represent a young woman, aged 19, whose 
spinal extensor muscles became paralyzed as the result of an attack 
of measles when she was about 13 years of age. The unopposed pull 
of the ilio-psoas muscles produced the extreme lordosis that may be 
seen in the illustrations. The pelvic inlet in this case looked actually 
downward and the pelvic outlet directly backward. The external 
measurements were: iliac spines, twenty-two and a half centimetres; 
iliac crests, twenty-six centimetres ; external conjugate, fifteen and a 
half centimetres; tuberosities of the ischia, ten centimetres (a large 
measurement compared with the others). The extreme rotation'of 
the pelvis on its transverse axis carried the external genitals with 
it so that they looked almost directly backward. Coitus in the usual 
posture would have been impossible. The upper edge of the pubic 
hair was more than five centimetres above the upper edge of the 
symphysis, the skin of the lower abdomen being unable to follow the 
pelvis in its backward movement. No position which this girl could 
assume would have much diminished the pelvic obliquity, so that, 
were she in labor, the process would be seriously retarded by the pelvic 
obliquity itself as well as by the influence of this obliquity upon the 
development of the pelvis. 
Figs. 5, 6, and 7 represent an Italian woman, 25 years of age, who 
had had three children, all destroyed in labor. She had been in this 
country about seven years, and all her children had been born here; the 
first four and a half years ago. The osteomalacia, from which she suf- 
fered, had begun after the birth of the first child. In the last four years 
she has lost more than six inches in height, and now her trunk is so 
much shortened that the floating ribs are telescoped within the false 
pelvis. The spinal column has bent so far backward in the dorsal 
region that the same result is produced upon pelvic obliquity and, to a Fig. i. 
Fig. 2. 
Fig. 3. 
Fig. 4. 
Fig. 5. 
Fig. 6. 
Fig. 7. Influence of Habitual hiclination of Pelvis on Pelvic Canal. 
3 
degree, upon pelvic form as though there had been a true kyphosis 
since childhood. The external pelvic measurements were as follows : 
Iliac spines cm. 
Iliac crests “ 
Trochanters .... 29 “ 
External conjugate . . 17y2 “ 
Transverse of outlet “ 
Ensiform cartilage to symphysis “ 
Posterior superior spinous processes of ilia . 7 
The upper edge of the symphysis was a considerable distance 
above the upper edge of the pubic hair. The anterior wall of the 
pelvis was sensitive, and the bones yielded to pressure. 
The sacrum was twisted on its longitudinal diameter so that the 
right side of the bone was much more prominent than the left. On an 
internal examination, the pubic rami were so closely approximated that 
it was difficult to insert a finger between them. The sacral curve was 
exaggerated, as in rachitis, but the angulation was more pronounced. 
The pelvis, in short, presented a queer combination of the rachitic 
and the kyphotic types. 
I did an oophorectomy on this patient in the hope of arresting the 
progress of her disease, but unfortunately she became wildly maniacal 
after the operation, tossed about in'the most violent fashion, and at 
length pulled the stump on one side from its ligature and bled to death. 
It has been repeatedly asserted that deformed pelves are rare in 
this country, but this assertion, as regards our larger cities, is refuted 
by my own experience and by that of every one who takes the trouble 
to observe the pelves in his pregnant and parturient patients. 
During the past twelve months I have had under my care, in labor, 
two rachitic dwarfs, two women with obliquely contracted pelves, some 
half-dozen cases of rachitic pelvis and a larger number of generally 
contracted and of simple flat pelves.