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A MANUAL OF ANATOMY 



side, and it terminates near the ileo-caecal junction in the last 

 ramus intestini tenuis, which anastomoses with the ileal branch 

 of the ileo-colic artery. The vessel is surrounded by a tough sheath 

 formed by the superior mesenteric sympathetic plexus. 



Branches — Left Branches. — These are called the rami intestini 

 tenuis, and are at least twelve in number. They pass downwards 



Fig. 312. — The Superior Mesenteric Artery and its Branches 

 (after Tiedemann). 



1. Superior Mesenteric Artery 



2. Rami Intestini Tenuis 



3. Ileo-colic 



4. Right Colic 



5. Middle Colic 



6. Inferior Pancreatico-diiodenal 



7. Duodenum 



8. Jejunum 



9. Ileum 



10. Caecum 



11. Ascending Colon 



12. Transverse Colon 



and to the left between the two layers of the mesentery proper, and 

 supply the jejunum and ileum. After a course of about 2 inches 

 each divides into two branches, which by their junction with con- 

 tiguous branches give rise to primary arches. From the convexities 

 of these arches small branches are given off, which act in a similar 

 manner, and give rise to secondary arches. This disposition of 

 arteries goes on so as to form tertiary, quaternary, and even 



