LIGAMENTS OF THE PELVIS. 277 



verge, and are inserted into the spinous process of the ischium, 

 by embracing it. The fibres constituting its base-, have their 

 fasciculi separated by cellular adipose matter and by vessels, 

 and are also intermingled with the fibres of the coccygeus mus- 

 cle, and of the posterior sacro-sciatic ligament. 



The two sacro-sciatic ligaments supply, in some degree, the 

 place of bone, and form a part of the inferior lateral parietes of 

 the pelvis. They convert the sciatic notch into a foramen, or, 

 rather, form with it two foramina; the upper and larger of 

 which transmits the pyriformis muscle, the sciatic nerve, and 

 the gluteal blood vessels; while the lower, placed between 

 the insertion of the two ligaments, transmits the obturator in- 

 ternus muscle, and brings the internal pudic artery into the 

 pelvis. 



The Obturator Ligament (Membrana Obturatoria) is extend- 

 ed across the foramen thyroideum, so as to close it up, with 

 the exception of a foramen at its upper part, for transmitting 

 the obturator vessels and nerves. It is a thin, but strong mem- 

 brane, having its fasciculi of fibres passing in various -directions, 

 and arising from the margin of the foramen. It affords origin 

 to many of the fibres of the obturator muscles. Sometimes 

 portions of it are defective. 



The Articulation of the Pubes is formed between the bodies 

 of the two ossa pubis. It consists principally in a fibro-carti- 

 laginous matter, which has a strong resemblance to that of the 

 vertebras. When the bones are torn apart by bending them 

 forwards, the fibrous arrangement becomes very apparent, and 

 is seen to consist in concentric lamella?, the fibres of which cross 

 one another. Sometimes in the male, but most frequently in 

 the female, the posterior third of the articulation is deprived of 

 these fibres, in place of which we find, in the middle of the 

 cartilage, a small longitudinal cavity, the surface of which is 

 smeared with a kind of mucosity. There is no central pulpy 

 matter in this articulation, as there is between the vertebras. On 

 its posterior surface it often makes a ridge projecting into the 

 cavity of the pelvis. From frequent observations made in our 

 dissecting-rooms, I have no doubt that this articulation is al- 

 ways very much relaxed in the parturient and pregnant female, 



VOL. I. 24 



