ILIAC FOSSA (EXTRA-PERITONEAL). 189 



to direct the faeces out of the body, but not on into their 

 proper channel. 



SUEGICAL ANATOMY OF THE ILIAC FOSSA 

 (EXTRA-PEK1TONEAL). 



The iliac fossa forms the inner aspect of the region 

 just described, and is of great surgical interest. From 

 within outwards the structures successively met with 

 are, the peritoneum, the subperitoneal fat and cellular 

 tissue, which contains a large amount of fat, allowing 

 the peritoneum to be readily stripped off, in ligature 

 of the vessels, the common and external iliac arteries 

 and their veins, the fascia iliaca, which is a continuation 

 of the fascia transversalis, and has attachments to the 

 crest of the ilium, Poupart's ligament, and vertebral 

 column. Beneath the fascia are the circumflex ilii ar- 

 tery and veins, the iliacus and psoas muscles, in the 

 substance of which is the anterior crural nerve ; upon 

 the former muscle are seen the external cutaneous and 

 the ilio-inguinal, and upon the latter the genito-crural 

 nerves, and the nutrient vessels derived from the ilio- 

 1 urn bar. 



The chief points of surgical importance refer to liga- 

 ture of the vessels, the common and external iliac arte- 

 ries, and abscesses. 



The Common Iliac. The course taken by this vessel, 

 with regard to the surface of the body, is from a point 

 to the left of the umbilicus, and in a line with the iliac 

 crests and the centre of Poupart's ligament. After the 

 intestines and peritoneum have been raised, it will be 

 seen that the aorta bifurcates, or does generally, on the 

 left side of the fourth lumbar vertebra, consequently the 



