THE LARGE INTESTINE 269 



lengthwise with the bowel, measuring from J to 4 

 inches in length. Usually ten to sixty are present. 

 They are found mostly in the ileum. Peyer's patches 

 are highly inflamed in typhoid fever, and ulcerate, 

 giving rise to hemorrhage and perforation of the bowel 

 in severe attacks of the disease. (See Fig. 83, page 

 204, for blood-supply of the small intestines.) 



THE LARGE INTESTINE 



The large intestine is that part of the alimentary 

 canal which extends from the end of the ileum to the 

 anus; it is about 5| feet long. It commences by a 

 dilated part, the cecum, in the right iliac fossa, ascends 

 to the under surface of the liver, then runs transversely 

 across the abdomen to the vicinity of the spleen, 

 descends to the left iliac fossa, and forms the sigmoid 

 flexure, and finally passes along back of the pelvis to 

 end at the anus. 



The Cecum. The cecum is the large cul-de-sac 

 which is the beginning of the large intestine, and is 

 about 3 inches broad and 2 J inches long. It is variously 

 situated, being found upon and external to the psoas; 

 upon the iliacus muscle it lies internal, on the pelvic 

 brim, or entirely within the pelvis. In any of these 

 positions it is entirely surrounded by peritoneum. 



The vermiform appendix comes off from the inner 

 and back part of the cecum, near its lower end, and 

 extends upward and inward behind it. This is a 

 piece of gut of the diameter of a goose-quill, varying 

 from 3 to 6 inches in length, curved upon itself, and 

 ending in a blind extremity. It tapers gradually to 

 its end, which is blunt, is completely invested by the 

 peritoneum, which forms for it a mesentery (meso- 

 appendix), and at its connection with the cecum is 

 guarded by an imperfect valve (valve of Gerlach) . This 

 is not always constant. 



The ileocecal valve guards the opening of the small 



