428 DISSECTION OF THE ABDOMEN. 



iliac fasciae lining the interior of the abdominal cavity, with the sheath on 

 the femoral vessels to which they give origin at Poupart's ligament. 



The peritoneum lines the inner surface of the abdominal wall, without 

 having any aperture for the escape of the intestine ; and its thinness and 

 weakness are apparent now it is detached. 



The subperitoneal fat extends as a continuous layer beneath the perito- 

 neum, but is thickest and most fibrous at the lower part of the abdomen, 

 where the iliac vessels pass under Poupart's ligament. At that spot it 

 extends over the upper opening of the membranous sheaths around the 

 vessels; and internal to the vein, it covers t,he space of the crural ring, as 

 well as a lymphatic gland which occupies that space. 



Where this layer stretches over the crural ring it is named by M. Clo- 

 quet septum crarale ; and it is described by him as being concave towards 

 the abdomen, and convex towards the thigh. An inguinal gland is gen- 

 erally attached to its under surface. 



The fascia transversalis has been before noticed (p. 417). At Pou- 

 part's ligament it joins the iliac fascia, outside the situation of the large 

 iliac artery (fig. 141) ; but internal to that spot it is continued downwards 

 to the thigh in front of the femoral vessels, and forms the anterior part of 

 the crural sheath. 



The iliac fascia covers the iliacus muscle, and lies beneath the iliac 

 vessels. At Poupart's ligament its disposition is similar to that of the 

 transversalis fascia; for, external to the iliac vessels, it joins the fascia 

 transversalis along the line of the ligament ; but opposite the vessels it is 

 prolonged into the posterior part of the crural sheath. 



Fig. Ml. 



Muscles : 



A. Iliacus covered by the iliac fascia. 

 B Rectus. 



c. Transversalis, covered by the trans s er- 

 salis fascia. 



D. Crural ring. 



E. Giinbernat's ligament. 

 Vessels : 



a. Iliac artery. 

 6. Iliac vein. 



c. Epigastric branch. 



d. Circumflex iliac. 



e. Obturator, with its nerve. 



/. Small branch joining obturatar and epi- 

 gastric arteries. 

 VIKW OP THE PARTS COXCKRNED IN FEMOKAL HERNIA (Quain's plates). 



The crural sheath is a loose membranous tube, which incloses the femo- 

 ral vessels as they enter the thigh, and is obtained from the fascia; lining 

 the abdomen. Its anterior half is continuous with the fascia transversalis, 

 and its posterior is derived from the fascia iliaca. The sheath is not en- 

 tirely filled by the vessels, for a space (crural ring) exists on the inner 

 side of the vein, through which the intestine descends in femoral hernia. 



The crural ring (fig. 141, D ) is referred to also in the dissection of the 

 thigh, but its boundaries are better seen in the abdomen. It is the inter- 

 val in the sheath, at the inner side of the femoral vein, which is about 

 half an inch wide, and is filled by a lymphatic gland. Bounding it inter- 

 nally, are Giinbernat's ligament, E, and the conjoined tendon; and limit- 



