380 DISEASES OF THE G ASTRO-INTESTINAL TRACT. 



pervious. By reason of the interference with its blood- 

 supply, if the constriction is not relieved, gangrene sooner 

 or later ensues. 



Volvulus is another frequent cause of intestinal obstruction. 

 There is either a twist of the bowel on its long axis, or, more 

 frequently, a loop of intestine is twisted around its mesenteric 

 attachment. The sigmoid flexure is the most frequent seat 

 of its occurrence. 



Intussusception, or invagination, is more frequent in chil- 

 dren than in adults, occurring usually at the ileo-csecal valve. 

 One part of the intestine slips over another, the length of the 

 invagination, which is nearly always downward, varying from 

 a few inches to several feet (Fig. 172). Thus the caecum and 



FIG. 172. 



J 



" I -*" ""- . _'; ,; ^.^"^ 



Ileo-csecal intussusception of minor degree. To the right is seen the appendix 

 vermiformis just about to be swallowed (Hutchinson). 



lower part of the ileum may be pushed into the colon until 

 the ileo-csecal valve even reaches the rectum. Gangrene and 

 a fatal peritonitis are the usual termination. 



Inflammations. 



Inflammatory processes may involve more or less the entire 

 length of the intestinal tract entero-oolitis or be more par- 

 ticularly limited to one of its subdivisions, suggesting the 

 terms duodenitis, colitis, ileo-colitis, typhlitis, proctitis, etc. 



Enteritis inflammation of the small intestine is an 



