216 



SPECIAL ANATOMY OF THE SKELETON 



same point on the opposite; its average measurement is five inches in the male, 

 five and one-fourth inches in the female. The oblique diameter (diameter obliqua) 

 extends from the margin of the pelvis, corresponding to the iliopectineal eminence 



FIG. 170. Male pelvis (adult). 



on one side, to the sacroiliac articulation on the opposite side; its average measure- 

 ment is four and one-fourth inches in the male and five in the female. 



The cavity of the true pelvis is bounded in front by the symphysis pubis; behind, 

 by the concavity of the sacrum and coccyx, which, curving forward above and 



FIG. 171. Female pelvis (adult). 



below, contracts the inlet and outlet of the canal; and laterally it is bounded by 

 a broad, smooth, quadrangular surface of bone, corresponding to the inner surface 

 of the body of the ischium and that part of the ilium which is below the ilio- 



