240 ANATOMY OF THE RABBIT 



Trace the branches of the superior mesenteric artery as follows: 



(a) The middle colic artery (a. colica media), a small vessel 

 (frequently two) arising from the left wall and passing to- 

 the transverse colon. 



(6) The inferior pancreaticoduodenal artery (p. 236) arises at 

 the same level, but from the right wall. 



(c) The ileocaecocolic artery (a. ileocaecocolica), a large 

 branch, equalling in size the superior mesenteric trunk, is. 

 distributed to the terminal portion of the ileum, the caecum 

 (including the vermiform process), and the ascending colon. 

 Its branches are arranged in two series, a proximal group 

 being given off near the point of origin of the main vessel, 

 and a distal group, including the terminal portion of the 

 vessel, at about two inches from the point of origin. 



The proximal branches of the ileocaecocolic artery include: 



(1) Small branches to the third, fourth, and fifth limbs of 

 the ascending colon, each anastomosing with its 

 neighbours, and the last with the middle colic arter}'. 



(2) The appendicular artery (a. appendicularis) to the 

 vermiform process. This vessel also gives off several 

 short branches to the immediately adjacent part of the 

 ileum and a longer branch, arising from the appendicular 

 near its point of origin, passes along the ileum to 

 anastomose with an intestinal branch of the superior 

 mesenteric trunk (top of p. 241). 



(3) An anterior ileocaecal artery to the terminal fourth 

 (anterior part of the third limb) of the caecum proper 

 and related portion of the ileum. 



(4) An anterior right colic artery to the flexure uniting the 

 first and second limbs of the ascending colon. 



(5) A posterior right colic artery to the second limb of the 

 ascending colon. This vessel anastomoses with (4) 

 and with the special branch to the third limb (1). 



The distal branches of the ileocaecocolic artery include: 



(6) A posterior ileocaecal artery to the middle portion of 



