LESSER MESENTERIC ARTERY. 407 



GREAT MESENTERIC ARTERY. 



(Fjg. 155, 2.) 



The anterior or great mesenteric artery arises a little behind 

 the coeliac axis, and splits into left, right, and anterior divisions. 

 The left consists of a score or so of branch lets, which pass to the 

 mesentery, being arranged in a radiating -manner between its 

 folds, and inosculating with each other near the lesser curvature 

 of the small intestine, so forming arches, from which twigs 

 proceed to the intestine. The first of these branches anastomoses 

 with the duodenal branch of the hepatic. 



The right division divides into ileo-csecal, superior and inferior 

 csecal, and right colic arteries. The ileo-ccBcal passes in the 

 mesentery along the ileum, and inosculates with the last branch 

 of the left division. The superior or internal ccecal goes to the 

 upper, the inferior or external coical to the lower fissure of the 

 caecum ; as it crosses the junction of the colon and csecum, it 

 supplies the artery of the arch which winds partly round the 

 origin of the colon. The right colic supplies the first and second 

 portions of the large colon, inosculating with the left colic at 

 the pelvic flexure. 



The anterior division consists of the left colic or retrograde, 

 and a branch to the floating or single colon ; near its origin it 

 gives off a branch to the pancreas. The retrograde runs parallel 

 with the right colic, inosculating with it, and supplying 

 the third and fourth portions of the great colon. The artery 

 of the floating colon anastomoses with the posterior mesenteric 

 artery. 



LESSER MESENTERIC ARTERY. 



(Fig. 155. 5.) 



The posterior or lesser mesenteric artery originates at from 

 three to four inches behind the great mesenteric ; longer but less 

 capacious than the latter, it divides into thirteen or fourteen 

 branches, which supply the floating colon and rectum, one branch 

 anastomosing with the artery of the floating colon from the 

 anterior mesenteric. They lie in the folds of the colic mesentery, 

 and the first eight form arches as in the anterior mesentery, but 

 the rest, which chiefly supply the rectum, break up singly without 

 forming arches ; these are known as the hcemorrhoidal arteries. 



