VISCEEAL BEANCHES OF THE ABDOMINAL AOETA. 



931 



part of the duodenum ; opposite the latter it enters the root of the mesentery, 

 in which it continues to descend, curving obliquely from above downwards and to 

 the right, to the right iliac fossa, and crossing, in this part of its course, obliquely 

 in front of the aorta, the lower part of the inferior vena cava, the right ureter, and 

 the right psoas major muscle. At its origin it lies posterior to the neck of the 

 pancreas and the splenic vein ; where it passes in front of the duodenum it is crossed 



Mesocolon transversum 



Colon transversum 



Intestinum 



iejunum 



A. mesenterica 



superior 



Aa. jejunales 



ileocolica -' 



i .uterior ileocsecal 

 branch - 



jsterior ileo-csecal 

 (. branch r 



\. appendicularis .- 



L^ Ileum 



FIG. 772. THE SUPERIOR MESENTERIC ARTERY AND ITS BRANCHES. 



Note the difference in the number and arrangement of the loops formed by the 

 jejunal branches as contrasted with the ileal branches. 



anteriorly by the transverse colon ; and in the lower part of its extent it is behind 

 the coils of small intestine. 



Branches. It gives off numerous branches which supply the duodenum and the 

 pancreas in part, the whole of the small intestine below the duodenum, and the large 

 intestine nearly as far as the left colic flexure. 



The branches are as follows : 



(a) The intestinal branches to the small intestine, varying from ten to sixteen in 



60 a 





