258 



INTESTINAL DIGESTION. 



right iliac fossa, to the left iliac fossa, thus encircling the convoluted mass 

 formed by the small intestine, in the form of a horseshoe. From the caecum 



to the rectum, the canal is 

 known as the colon. The 

 first division of the colon, 

 called the ascending colon, 

 passes almost directly up- 

 ^ ward to the under surface 

 of the liver ; the canal here 

 turns at nearly a right an- 

 gle, passes across the upper 

 part of the abdomen and 

 is called the transverse co- 

 lon ; it then passes down- 

 ward at nearly a right an- 

 gle, forming the descend- 

 ing colon. The last divis- 

 ion of the colon, called the 

 sigmoid flexure, is situated 

 in the left iliac fossa and 

 is in the form of the italic 

 letter S. This terminates 

 in the rectum, which is not 

 straight, as its name would 

 imply, but presents at least 

 three distinct curvatures, 

 as follows : it passes first 

 in an oblique direction 

 from the left sacro-iliac 

 symphysis to the median 



FIG. 78. Stomach, pancreas, large intestine etc. (Sappey). , . , . 



1, anterior surface of the liver ; 2, gall-bladder ; 3, 3, section of lme Opposite the third 



the diaphragm ; 4, posterior surface of the stomach ; 5, lobus -ninnn ~4? +!- cio^^n . if 



Spigelii of the liver ; 6, cceliac axis ; 7, coronary artery of the Pi^Ce OI tne Sacrum , It 



stomach ; 8, splenic artery ; 9, spleen : 10, pancreas ; 11, supe- f npT1 r^oQpa rlnwnwarrl in 



rior mesenteric vessels ; 12, duodenum ; 13, upper extremity tnen P a SS6S downward in 



of the small intestine ; 14, lower end of the ileum ; 15, 15, mes- f np mprlian linp fnllnwino- 



entery ; 16, ccecum ; 17, appendix vermiformis ; 18, ascending l Lie ' 1V lia & 



colon ; 19, 19, transverse colon ; 20, descending colon ; 21, sig- fV, p ponpnvitv of thp saoriim 



moid flexure of the colon ; 22, rectum ; 23, urinary bladder. Heavily O. 



and coccyx ; and the lower 



portion, which is about an inch (2*54 centimetres) in length, turns backward 

 to terminate in the anus. 



The caecum, or caput coli, presents a rounded, dilated cavity continuous 

 with the colon above and communicating by a transverse slit with the ileum. 

 At its lower portion is a small, cylindrical tube, opening below and a little 

 posterior to the opening of the ileum, called the vermiform appendix. This 

 is covered with peritoneum and has a muscular and a mucous coat. It is 

 sometimes entirely free and is sometimes provided with a short fold of mes- 

 entery for a part of its length. The coats of the appendix are very thick. 

 The muscular coat consists of longitudinal fibres only. The mucous mem- 



