SUPERIOR MESENTERIC 



559 



teric as that vessel emerges from tlie contiguous margins of the i)ancreas and 

 transverse duodenum or from its first intestinal Ijranch, and, crossing ])ehind the 

 superior mesenteric vein, courses upwards and to the right l)etween the head of 

 the pancreas and the duodenum, beneath the ascending layer of the transverse 

 meso-colon, to anastomose with the superior pancreatico-duodenal, which is given 

 off from the gastro-duodenal, and descends in a like situation beneath the ascend- 

 ing layer of the transverse meso-colon. 



(2) The middle colic, arising from the concavity of tlie superior mesenteric a 

 little below the pancreas, enters the transverse meso-colon, and divides into two 

 branches — one of which passes to the left and anastomoses with the ascending 



Fig. 366. — The Superior Mesenteric Artery and Vein. 

 (The colon is turned up, and the small iutestines are drawn over to the left side.) 



Left colic artery 



Superior nifseii- 

 teric artery and 

 vein 



Ileo-colic artery 



VERMIFORM 

 APPENDIX 



]'asa intestini 

 tenuis 



SMALL INTEST'NES 





branch of the left colic; the other, winding downwards and to the right, 

 anastomoses with the ascending branch of the right colic. 



(3) The right colic — sometimes given off as a common trunk either witli the 

 former branch or with the ileo-colic — passes to the right behind the peritoneum to 

 the back of the ascending colon, Avhere it divides into an ascending branch, Avhich 

 anastomoses with the descending branch of the middle colic, and a descending 

 branch which anastomoses with the ascending or colic branch of the ileo-colic. 



(4) The ileo-colic descends behind the peritoneum towards the caecum, where 

 it divides into a colic branch which tracks ui)wards beneath the peritoneum to 

 anastomose with the descending branch of the right colic; and into an ileac branch 

 which passes between the layers of the mesentery and anastomoses with the 

 termination of the superior mesenteric artery. 



