DISSECTION OP THE ABDOMEN. 297 



pelvic cavity, the bowel forms in the iliac or hypogastric region a second 

 flexure — the pelvic flexure, the angle of which marks the point of separa- 

 tion between the 2nd and 3rd portions. The 1st and 2nd portions of the 

 double colon have extensive contact with the abdominal wall, and they 

 conceal the other two divisions of the bowel, which lie above them (in the 

 natural standing posture). 



The 3rd division, beginning at the pelvic flexure, extends forwards 

 along the left side of the abdomen, through the same areas as the 2nd 

 portion, being closely bound to it, and lying immediately above it. On 

 reaching the epigastric region, a third flexure is formed, in contact with 

 the diaphragm, liver, and stomach, and from these relations named the 

 diaphragmatic or gastro-hepatic flexure. This will be brought into view 

 by grasping and pulling backwards the siiprasternal flexure, above which 

 it lies. 



The 4th portion begins at the angle of the diaphragmatic flexure, and 

 passes backwards on the right side of the cavity, lying above the 1st 

 division, and closely bound to it. On reaching the inner side of the 

 crook of the caecum, to which it is adherent, it suddenly becomes much 

 reduced in calibre, and is continued as the small or floating colon. 



The pelvic flexure of the colon should now be seized and carried for- 

 wards, so as to place the bowel in the position shown in Plate 41, It will 

 now be observed that the bowel is quite unattached except at its beginning 

 and termination, where it adheres to the pancreas and the crook of the 

 csecum. In this disposition the suprasternal and diaphragmatic flexures 

 are obliterated, and the 1st and 4th portions are seen to be closely 

 adherent to one another, and, in like manner, the 2nd and 3rd portions, 

 except just at the pelvic flexure, where, in the angle of the flexure, a small 

 space is bridged over by a racket-shaped piece of peritoneum. It will be 

 noticed also that the intestine varies greatly in calibre at different 

 points. Its greatest diameter is in its 4th portion, and its smallest 

 about the centre of the 3rd. This narrow portion of the intestine is 

 fui-ther distinguished from the rest by being not puckered, but plain, 

 when distended. 



The Small or Floating Colon succeeds the double colon. It is much 

 narroAver than that bowel, indeed it does not greatly exceed in calibre 

 the small intestine, from which, however, its coils are readily distin- 

 guished by their puckered appearance. In a medium-sized animal it is 

 aboi\t ten feet in length. It is disposed within the abdomen after the 

 manner of the small intestine, being suspended at the free edge of a de- 

 pendency of the peritoneum, termed the vieso-colon or colic mesentery. It 

 has a convoluted disposition, and occupies the left lumbar and iliac 

 regions. Its last coil passes into the pelvic cavity, and is continued as 

 the rectum. 



The Rectum is the terminal portion of the intestine, and is about two 



