SPERMATIC ARTERIES. 303 



The Vasa intestini tennis 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 

 termination 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 produced. By means of these arches a direct communication is 

 established between all the branches given off from the convexity of 

 the superior mesenteric artery ; the superior branches moreover sup- 

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

 duodenalis; and the inferior with the ileo-colica. 



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

 vity 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 

 ca3cum, and the commencement of the colon. This artery inoscu- 

 lates 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 infe- 

 rior mesenteric 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 directed 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 lies in front of the vena cava, and both ves- 

 sels are accompanied by their corresponding veins and by the sper- 

 matic plexuses of nerves. 



The spermatic arteries in the female descend into the pelvis and 

 pass between the two layers of the broad ligaments of the uterus, to 

 be distributed to the ovaries, Fallopian tubes, and round ligaments; 

 along the latter they are continued to the inguinal canal and labium 

 at each side. 



They inosculate with the uterine arteries.' 





