124 



Anatomy of Skeleton 



Notice also that, when the pelvis is in position, the vertical plane of the anterior 

 superior spines is only just behind that of the symphysis in men, and just in front of 

 it in women, owing to the slightly greater obliquity of pelvis in them. 



Further details of pelvic structure, including other minor sexual characters, will 

 be better considered in connection with the innominate bones, while certain others 

 have already been discussed under the Sacrum ; but before returning to the os inno- 

 minatum it may be pointed out here that the distinction between male and female 

 pelvis can be made as early as the third or fourth month of development, and it can 



FIG. 102. Outlines drawn from a series of average measurements of male and 

 female bones and superimposed for comparison. The male outline is inter- 

 rupted. It can be seen that the female pelvis is broader and deeper, while 

 the false pelvis is not so wide as in the male, nor its crest so prominent ; the 

 male crest is also more curved and turned in front, but this last character 

 is not usually so marked as it appears in this imaginary outline. It must not be 

 forgotten that the female false pelvis is relatively wider than it seems in the 

 diagram, because of shorter stature. 



be stated that the appearance of the pubic arch (Fig. 100) is the best and most reliable 

 test of sex in the bony pelvis. 



Detailed Consideration of Os Innominatum. 



The general " build " of the bone is associated with the transference of weight 

 Irom the vertebral column to the heads of the femora. The bone can be placed in the 

 position it occupies in the complete pelvis by holding it so that the plane of its sym- 

 physial articular surface is sagittal, while the cotyloid notch is opening directly down- 

 wards : when held thus it can be seen that the os innominatum admits of division 

 into two parts that lie in different planes. The upper and back portion looks in general 



