LIGAMENTS OF THE PELVIS. 275 



dnterius) is placed on the forepart of the latter bone ; runs its 

 whole length, and arises from the inferior extremity of the sa- 

 crum. Its fibres are rather indistinct, from their being blended 

 with fat : on the lateral margins of the coccyx they are rather 

 better marked. 



The Posterior Coceygeal Ligament, (Lig. Sacro-coccygeum 

 Posterius,) as its name implies, is placed on the back part of the 

 coccyx. It arises from the inferior margin of the spinal canal 

 of the sacrum, arid forms a sort of membranous expansion, 

 which passes the first bone of the coccyx, and is inserted into 

 the second. There are also a few other ligamentous fibres con- 

 necting the bones of the coccyx. 



The Ilio Lumbar ligament (Lig. llio Lumbare) arises from 

 the transverse process of the last lumbar vertebra, and from its 

 inferior oblique process, and going outwards is inserted for two 

 inches into the crista of the ilium. It is often blended with 

 adipose matter, which separates it into several fasciculi. Cal- 

 dani describes it as two ligaments, making a distinction between 

 the one part from the transverse, and the other from the ob- 

 lique process. 



The Sacro-Iliac Articulation is formed by the corresponding 

 surfaces of the sacrum and ilium. Each bone is incrusted with 

 its own cartilage, the one on the sacrum being somewhat more 

 thick. Their surfaces are slightly rough, and between them 

 exists a thick yellow fluid in a very small quantity, which lu- 

 bricates them, and is more abundant in early life. 



The Sacro- Spinous Ligament (Lig. Sacro Spinosum) is 

 placed superficially on this articulation behind. It is very 

 strong, flat, long, and perpendicular. It consists of two lamince, 

 of which the more superficial arises from the posterior supe- 

 rior spinous process of the ilium, and is inserted into the fourth 

 transverse process of the sacrum. The deep-seated lamina 

 arises from the same point, and is inserted into the third trans- 

 verse process of the sacrum. Bichat describes, connected with 

 the inferior margin of this ligament, a fasciculus, which comes 

 from the posterior inferior spinous process of the ilium. 



