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. 



THE LOWER MESEXTERIC ARTKRY, AND THE AORTA, seeu by turning aside the upper iueseijte:ic 



artery and the small intestine. (Tiedemann). 



a. Aorta. /. Upper ruesenteric. 



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 sifjmnid artery (d) is distributed to the sigmoid flexure, and 

 divides into offsets which anastomose above with the preceding colic, 

 and below with the tuemorrhoidal branch. Here, as in the rest of the 

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

 intestine. 



