The Intestines. 225 



The ileo-c cecal valve projects into the lumen of the 

 large bowel, and is a narrow slit formed by two trans- 

 verse bands. Its formation and direction favor the pass- 

 age of the contents of the ileum into the caecum, but pre- 

 vent backflow from the latter. The ascending colon, 

 about eight inches long, passes up through the right lum- 

 bar and hypochondriac regions and terminates at the under 

 surface of the liver, a little external to the gall bladder, at 

 which point it bends forwards, and to the left, as the 

 hepatic flexure. Relations : It lies in front of the quad- 

 ratus lumborum, the second part of the duodenum and the 

 right kidney, and is surrounded, as a rule, on the front 

 and sides only, by peritoneum, though in twenty-six out of 

 one hundred subjects examined by Treves there was a 

 meso-colon present. The transverse colon, about twenty 

 inches in length, passes across the abdomen from the he- 

 patic flexure on the right, towards the spleen, on the left. 

 It gradually ascends as it nears the spleen until the splenic 

 end is on a higher level than the hepatic end and at the same 

 time it is deeper placed in the abdomen, so that the left ex- 

 tremity of the transverse colon is about one inch nearer to 

 the posterior wall than the right extremity. The trans- 

 verse colon is the most movable part of the large intes- 

 tine, and, since it is longer than the body is wide, the ex- 

 tra length is accommodated by this portion of the bowel 

 looping downwards and forwards. Relations : It lies be- 

 neath the liver, the gall bladder, the greater curvature of 

 the stomach and the spleen ; is above the small intestines 

 and behind the abdominal walls, with the great omentum 

 hanging down from it, so as to cover, more or less, the in- 

 testines, thus protecting them by its heat-retaining proper- 

 ties, although Greig Smith states that it very rarely con- 

 forms to this description, being often coiled up or folded 

 on itself. The cavity of the great omentum is obliterated, as 



