338 THE ABDOMEN AND PELVIS 



colic near the left flexure of the colon. As the artery lies 

 somewhat to the right of the middle line, openings in the 

 transverse meso-colon are made on the left side (p. 301). 



- The lymph vessels of that portion of the large intestine 

 which is supplied by the superior mesenteric artery mainly 

 follow the course of the chief blood-vessels. The lymph glands 

 are divided by Jamieson and Dobson into four groups, (i) 

 The epi-colic lymph glands are situated on the wall of the gut. 

 (2) The para-colic lymph glands lie on the medial side of the 

 ascending colon behind the posterior parietal peritoneum ; and 

 above the transverse colon, between the two layers of its 

 mesentery. (3) The intermediate lymph glands are associated 

 with the ileo-colic, right, and middle colic vessels. (4) The 

 central group lies along the superior mesenteric vessels (Fig. 106). 



Efferents pass from the epi-colic to the para-colic lymph 

 glands, from the para-colic to the intermediate group, and from 

 the intermediate to the central group. Some efferents from 

 the bowel and epi-colic lymph glands pass directly to the 

 intermediate group, and, on this account, the latter must be 

 removed together with the bowel and the para-colic lymph 

 glands in malignant disease (p. 339). In removing retro- 

 peritoneal lymph glands, the peritoneum which covers them 

 must also be taken away. This leaves a part of the posterior 

 abdominal wall bare, and the surrounding peritoneum requires 

 to be undermined before it can be drawn together over the 

 denuded area. 



Removal of Caecum and Ascending Colon. The parts 

 dealt with in this operation are more or less fixed in position, 

 and their blood and lymph vessels lie behind the posterior 

 parietal peritoneum. For these reasons the resection of the 

 ascending colon presents more difficulty than the removal of 

 a part of the small intestine, where the gut is freely movable 

 and its blood and lymph vessels are easily controlled as they 

 lie in the mesentery. 



The extent of malignant or tuberculous disease in the ileo- 

 csecal region may be so limited that only a comparatively small 

 piece of the gut requires to be removed. If, however, the right 

 colic (hepatic) flexure is not freely movable, some difficulty may 

 be experienced in approximating the two cut ends in the subse- 

 quent anastomosis. Under these circumstances it is advantageous 

 to remove the flexure in addition to the diseased area, and the 

 more movable transverse colon can then be united to the ileum. 



