442 



DISSECTION OF THE ABDOMEN. 



eating with the superior mesenteric, assists to maintain the chain of anas- 

 tomosis along the intestinal tube. 



This vessel is of smaller size than the superior mesenteric, and arises 

 from the aorta, from one to two inches above the bifurcation. At first 

 the vessel descends on the aorta, and crosses the left common iliac artery, 

 as it courses to the pelvis to end in branches for the rectum (superior 

 haemorrhoidal). The following branches are furnished by it to the de- 

 scending colon and the sigmoid flexure. 







Fig. 144. 



.2 



"o 



o O 



<: G) 



THE LOWER MESENTERIC ARTKRT, AND THE AORTA, seen by turning aside the upper mesenteric 



artery and the small intestine. (Tiedemann). 



a. Aorta. /. Upper mesenteric. 



6. Inferior mesenteric artery. g. Renal. 



c. Left colic. h. Spermatic of the left side. 



d. Sigmoid, and e, Superior hsemorrhoidal 



branches. 



a. The left colic artery (c) ascends in front of the left kidney, and 

 divides into an ascending and a descending branch for the supply of the 

 descending colon : by the ascending offset it anastomoses with the middle 

 colic branch of the superior mesenteric. 



b. The sigmoid artery (d) is distributed to the sigmoid flexure, and 

 divides into offsets which anastomose above with tins preceding colic, 

 and below with the haemorrhoidal bi'anch. Here, as in the rest of the 

 intestinal tube, arches are formed by the arteries before they reach the 

 intestine. 



