440 



DISSECTION OF THE ABDOMEN. 



the splenic vein ; and as it descends to the mesentery it is placed in front 

 of the duodenum and the left renal vein. This vessel is surrounded by 

 the mesenteric plexus of nerves, and is accompanied by the vein of the 

 same name. 



Branches. Whilst the vessel is covered by the pancreas it gives a small 

 branch to that body and the duodenum. Its other branches are intestinal: 

 those from the left or convex side of the vessel (rami intestinales) are fur- 

 nished to the jejunum and ileum ; and those from the opposite side supply 

 the colon, and are named colic arteries. 



Fig. 143. 



SUPERIOR MESENTERIC ARTERY AND ITS BRANCHES (Tiedemann). 



a. Superior mesenteric. d. Right colic. 



b. Inferior pancreatico-duodenal. e. Ileo-colic. 



c. Middle colic. /. Intestinal branches to the jejunum and ilenm. 



a. The pancreatico-duodenal branch (inferior) is of small size (fig. 143, 

 b) ; after giving twigs to the pancreas, it runs to the right along the con- 

 cavity of the duodenum, and anastomoses with the other duodenal branch 

 (p. 448). 



b. The intestinal branches for the jejunum and ileum (fig. 143, f) are 

 about twelve in number, and pass from the left side of the artery between 

 the layers of the mesentery. About two inches from their origin the 

 branches bifurcate, and the resulting pieces unite with similar offsets from 

 the collateral arteries, so as to form a series of arches. From the con- 

 vexity of the arches other branches take origin, which divide and unite 

 as before. This process is repeated four or five times between the origin 



