318 SURGICAL APPLIED ANATOMY. [Chap. xvi. 



only open below where the fascia passes with its 

 muscle into the thigh. This opening being at the 

 most dependent part of the space, it follows that the 

 psoas or iliac abscess very commonly points on the 

 upper part of the thigh, just to the outer side of the 

 femoral vessels. An abscess in the iliac fossa, although 

 most likely to reach the thigh, might mount up to the 

 superior attachments of the fascia, and point at the iliac 

 crest, or at the outer part of Poupart's ligament. Or it 

 may disregard the inner attachments of the fascia and 

 gravitate into the pelvis. If the patient should occupy 

 for long the recumbent posture, there is no reason why 

 it should not extend upwards along the psoas muscle. 



The term iliac abscess, however, is often applied to 

 collections that are not within the space formed by the 

 iliac fascia, but that are situated rather in the subserotis 

 connective tissue. This tissue is very extensive in the 

 iliac fossae, and favours the formation of large purulent 

 collections. Kcenig's experiments of injecting fluid 

 into this subserous space show that an abscess so 

 placed may spread in any direction by simply dissect- 

 ing off the peritoneum. Clinically, however, such col- 

 lections are greatly limited by gravity. They are apt to 

 remain in the iliac fossa, bulging out the abdominal 

 wall just above Poupart's ligament, and occupying the 

 angle formed by the union of the iliac and transver- 

 salis fasciae. In some cases they are disposed to 

 extend into the pelvis. 



The abscess, when in the subserous tissue, is 

 brought in close contact with certain of the viscera, 

 especially with the caecum and sigmoid flexure, and 

 into these portions of the colon it may open. Thus, I 

 have seen a case of iliac abscess, due to pelvic necrosis, 

 that opened into the sigmoid flexure, and at the same 

 time discharged through sinuses about the eroin. Jn 



^ * 



this case some pus passed by the anus, while on the 

 other hand some faecal matter escaped by the groin. 



