OF THE PELVIS. 21 



for the psoas and iliac muscles; the ileo-pectineal eminence, for the 

 insertion of the lesser psoas; a triangular surface, smooth, inclined 

 forwards, and concealed by the pectinalis muscle; the crest; then the 

 spine of the pubis; and, lastly, the angle of the pubis. 



21. On its posterior edge, in proceeding from above doAvnwards, 

 is seen the posterior superior spine of the ilium; a small irregular 

 notch; the postero-inferior spine of the ilium, which articulates with 

 the sacrum; the great ischiatic notch; the ischiatic spine; the small 

 ischiatic notch, and the most posterior portion of the tuberosity of the 

 ischium. 



22. At birth, the coxal bone is composed of three distinct pieces: 

 one superior, the ilium, which constitutes the hip and the two iliac 

 fossa; one inferior, the ischium, which supports the weight of the 

 body when seated; the third, anterior, the pubis, to which are ap- 

 pended, as it were, the organs of generation. It is in the cotyloid 

 cavity, at the ileo-pectineal eminence, and in the middle of the ischio- 

 pubal ramus, that these three bones at length are blended into one 

 about the period of puberty; but there are commonly added in child- 

 hood, a plate for the crest of the ilium, one for the tuberosity of the 

 ischium, another point of ossification for the antero-inferior spine, 

 and a fourth for the spine of the pubis; which sometimes do not 

 coalesce with the principal pieces until a very late period. 



SECTION 2. 

 Of the Articulations, or Symphyses of the Pelvis. 



23. There are three principal articulations of the pelvis: one for 

 the two pubes in front, and two for the bones of the ilium and the 

 sacrum behind. 



24. At the anterior or median symphysis, the bones are kept in 

 contact by a fibro-cartilaginous substance called the interpubal liga- 

 ment, and whose thickness is far from being uniform at every point 

 of the kind of ring or oval circle which it represents. Its thickness, 

 which is very considerable on the upper part, a little less so in front, 

 and much less so behind, becomes suddenly much greater below, 

 where the fibrous body assumes the name of sub-pubal or triangular 

 ligament. In the centre, the articular surfaces are separated by a 

 very thin plate of cartilage, which in early life, and even in a good 

 many adult women, is moistened by a small quantity of synovial 

 fluid. 



A portion of the periosteum lines the posterior surface, a fibrous 

 lamina of the same material is observed in front, and these two layers 



3* 



