162 ANATOMY FOR NURSES. [CHAP. XIV. 



The large intestine. The large intestine is about five feet 

 long, and from two and a half to one and a half inches wide ; 

 it extends from the ilium to the anus. It is divided into the 

 csecum, with the vermiform appendix, the colon, and the rectum. 

 The coBcum (ccecus, blind) is a large blind pouch at the com- 

 mencement of the large intestine. The small intestine opens 

 into the side wall of the large intestine about two and a half 

 inches above its the large intestine's commencement, the 

 caecum forming a cul-de-sac below the opening. Attached to 

 the lower end of the csecum is a narrow, 

 worm-like tube about the size of a lead- 

 pencil, the vermiform appendix. The 

 csecum and appendix lie just beneath 

 the front abdominal wall in the right 

 iliac region (vide Plate VII.). The open- 

 ing from the ilium into the large intes- 

 tine is provided with two large project- 

 ing lips of mucous membrane which 

 allow the passage of material into the 

 large intestine, but effectually prevent 

 the passage of material in the opposite 

 direction. These mucous folds form 

 what is known as the ilio-csecal valve. 



FIG. 100. C^CUM, SHOW- 

 ING ITS APPENDIX, ENTRANCE The colon may be subdivided into the 



vUTVc'aLmT^Tom 1 : ascending, transverse, and descending 

 mencement of colon; 3, en- colon, and the sigmoid flexure. The 

 E2 4. ^."^ ending portion runs up on the right 

 6, aperture of vermiform ap- side of the abdomen until it reaches 



rmappen. 



left, and is continued straight across the abdomen as the trans- 

 verse colon until, reaching the left side, it turns abruptly and 

 passes downwards as the descending colon. Reaching the left 

 iliac region on a level with the margin of the crest of the ilium, 

 it makes a curve like the letter S, hence its name of sigmoid 

 flexure, and finally ends in the rectum. The rectum is from 

 six to eight inches long ; it passes obliquely from the left until 

 it reaches the middle of the sacrum, then it follows the curve 

 of the sacrum and coccyx, and finally arches slightly backwards 

 to its termination at the anus. The anal opening is guarded 

 by two circular muscles called, respectively, the internal and 

 external sphincters. 



