338 SPERMATIC ARTERIES. 



The branches of the superior Mesenteric Artery are 



Vasa intestini tenuis, 

 Ileo-colica, 

 Colica dextra, 

 Colica media. 



The Vasa intestini tenuis arise from the convexity of the superior 

 mesenteric artery. They vary from fifteen to twenty in number, and 

 are distributed to the small intestine from the duodenum to the termi- 

 nation of the ileum. In their course between the layers of the 

 mesentery, they form a series of arches by the inosculation of their 

 larger branches ; from these are developed secondary arches, and from 

 the latter a third series of arches, from which the branches arise which 

 are distributed to the coats of the intestine. From the middle 

 branches a fourth and sometimes even a fifth series of arches is pro- 

 duced. By means of these arches a direct communication is establish- 

 ed between all the branches given off from the convexity of the 

 superior mesenteric artery; the superior branches moreover supply the 

 pancreas and duodenum, and inosculate with the pancreatico-duodena- 

 lis; and the inferior with the ileo-colica. 



The Ileo-colic artery is the last branch given off from the concavity 

 of the superior mesenteric. It descends to the right iliac fossa, and 

 divides into branches which communicate and form arches, from which 

 branches are distributed to the termination of the ileum, the caecum, 

 and the commencement of the colon. This artery inosculates on the 

 one hand with the last branches of the vasa intestini tenuis, and on the 

 other with the colica dextra. 



The Colica dextra arises from about the middle of the concavity of 

 the superior mesenteric, and divides into branches which form arches, 

 and are distributed to the ascending colon. Its descending branches 

 inosculate with the ileo-colica, and the ascending with the colica 

 media. 



The Colica media arises from the upper part of the concavity of the 

 superior mesenteric, and passes forwards between the layers of the 

 transverse mesocolon, where it forms arches, and is distributed to the 

 transverse colon. It inosculates on the right with the colica dextra ; 

 and on the left with the colica sinistra, a branch of the inferior mesen- 

 teric artery. 



The SPERMATIC ARTERIES are two small vessels which arise from 

 the front of the aorta below the superior mesenteric ; from this origin 

 each artery passes obliquely outwards, and accompanies the corre- 

 sponding ureter along the front of the psoas muscle to the border of the 

 pelvis, where it is in relation with the external iliac artery. It is then di- 

 rected outwards to the internal abdominal ring, and follows the course of 

 the spermatic cord along the spermatic canal and through the scrotum 

 to the testicle, to which it is distributed. The right spermatic artery 



