316 



Arteries of 

 large gut. 



Ileo-colic 

 branch runs 

 to caecum. 



DISSECTION OF THE ABDOMEN. 



Right colic 

 branch sup- 



Slies ascend- 

 \g colon. 



Middle colic 

 branch 

 passes to 

 transverse 

 colon ; 



number and 

 arrange- 

 ment in 

 arches. 



Superior 



mesenteric 



vein. 



Mesenteric 

 glands ; 



lymphatics 



entering 



them. 



Meso-colic 

 glands. 



Dissection 

 of inferior 

 mesenteric 

 artery, 



and vein : 



The branches to the large intestine are three in number, ileo-colic, I 

 right colic, and middle colic arteries. 



c. The ileo-colic artery (e) arises from the right side of the trunk, I 

 and divides opposite the caecum into ascending and descending 

 branches. The ascending branch supplies the caecum and the 

 beginning of the ascending colon, and anastomoses with the right 

 colic artery ; while the descending branch joins in a loop with the 

 termination of the mesenteric trunk, and distributes offsets to the 

 lower end of the ileum. The ascending branch sends an artery 

 (appendicular) behind the termination of the ileum, which enters 

 the meso-appendix, and is distributed to the appendix. 



d. The right colic artery (d) is frequently conjoined at its origin 

 with the preceding. Near the ascending colon it divides into 

 ascending and descending branches, which anastomose with the 

 ileo-colic artery on the one side, and with the middle colic on the 

 other. 



e. The middle colic branch (c) springs from the upper part of the 

 artery, and entering between the layers of the transverse meso- 

 colon, divides into two branches ; the right one anastomoses with the 

 artery to the ascending colon, and the left with the left colic branch 

 of the inferior mesenteric artery (fig. 117, c). The intestinal twigs 

 are united in arches before entering the gut, like those to the small 

 intestine. 



The superior mesenteric vein (fig. 125, &, p. 334) is formed by the 

 union of branches from the intestine corresponding to the offsets of the 

 artery. The trunk passes beneath the pancreas on the right side of 

 the artery, and there joins the splenic vein to form the vena portae. 

 At the lower border of the pancreas it receives the right gastro- 

 epiplo'ic branch from the stomach. 



The MESENTERIC LYMPHATIC GLANDS are numerous between the 

 layers of the mesentery. An upper group lies by the side of the 

 artery, and contains the largest glands ; and a lower group, near the 

 intestine, is lodged in the intervascular spaces. The chyliferous 

 vessels of the small intestine, and the absorbents of the part of 

 the large intestine supplied by the superior mesenteric artery, pass 

 through the mesenteric glands in their course to the thoracic duct, 



Along the side of the ascending and the transverse colon are a few 

 other small lymphatic glands, meso-colic, which receive some absorb- 

 ents of the large intestine. 



Dissection (fig. 117). By drawing the small intestine over to the 

 right side, the dissector will observe the inferior mesenteric artery 

 on the front of the aorta, a little above the bifurcation. The peri- 

 toneum should be removed from its surface, and the branches 

 should be traced outwards to the remaining half of the large intes- 

 tine ; a part of the artery enters the pelvis, but this will be dis- 

 sected afterwards. On the artery and its branches the inferior 

 mesenteric plexus of nerves ramifies, and should be preserved, 

 especially near the origin of the vessel. 



The inferior mesenteric vein also is to be followed upwards 



