242 



OSTEOLOGY 



I 



The size of the pelvis varies not only in the two sexes, but also in different 

 members of the same sex, and does not appear to be influenced in any way by the 

 height of the individual. Women of short stature, as a rule, have broad pelves. 

 Occasionally the pelvis is equally contracted in all its dimensions, so much so 

 that all its diameters measure 12.5 mm. less than the average, and this even in 

 well-formed women of average height. The principal divergences, however, are 

 found at the superior aperture, and affect the relation of the antero-posterior 

 to the transverse diameter. Thus the superior aperture may be elliptical either 

 in a transverse or an antero-posterior direction, the transverse diameter in the 

 former, and the antero-posterior in the latter, greatly exceeding the other diameters; 

 in other instances it is almost circular. 



FIG. 242. Female pelvis. 



In the fetus, and for several years after birth, the pelvis is smaller in proportion 

 than in the adult, and the projection of the sacrovertebral angle less marked. 

 The characteristic differences between the male and female pelvis are distinctly 

 indicated as early as the fourth month of fetal life. 



Abnormalities. There is arrest of development in the bones of the pelvis in cases of extro- 

 version of the bladder; the anterior part of the pelvic girdle is deficient, the superior rami of 

 the pubes are imperfectly developed, and the symphysis is absent. "The pubic bones are sepa- 

 rated to the extent of from two to four inches, the superior rami shortened and directed forward, 

 and the obturator foramen diminished in size, narrowed, and turned outward. The iliac bones 

 are straightened out more than normal. The sacrum is very peculiar. The lateral curve, instead 

 of being concave, is flattened out or even convex, with the iliosacral facets turned more outward 

 than normal, while the vertical curve is straightened." 1 



The Femur (Thigh Bone). 



The femur (Figs. 244, 245), the longest and strongest bone in the skeleton, is 

 almost perfectly cylindrical in the greater part of its extent. In the erect posture 

 it is not vertical, being separated above from its fellow by a considerable interval, 

 which corresponds to the breadth of the pelvis, but inclining gradually downward 

 and medialward, so as to approach its fellow toward its lower part, for the purpose 

 of bringing the knee-joint near the line of gravity of the body. The degree of this 

 inclination varies in different persons, and is greater in the female than in the male, 



1 Wood, Heath's Dictionary of Practical Surgery, i, 426. 



