THE VISCERAL BRANCHES. 



803 



It passes downward and to the left, beneath the peritoneum and resting upon the 

 left psoas muscle, and, after having crossed the left common iliac, it terminates upon 

 the upper portion of the rectum, this terminal portion being called the superior hem- 

 orrhoidal artery. 



Branches.— («) The left colic artery (a. colica sinistra) arises shortly below the origin of 

 the artery and passes upward and to the left. It divides into an ascending and a descending 

 branch, the former of which passes between the two layers of the transverse mesocolon to inos- 

 culate with the middle colic branch of the superior mesenteric, while the descending branch, 

 entering the sigmoid mesocolon, anastomoses with the sigmoid arteries. From the arches thus 

 formed branches pass to the left portion of the transverse colon and to the whole of the descend- 

 ing colon. 



{b) The sigmoid branches (aa. sigmoideae ), two or three in number, are given off as the 

 inferior mesenteric crosses the left common iliac. They run downward and to the left over the 



Gastric artery 



Fig. 723. 



Transverse colon, turned upward 



Cceliac axis 



Hepatic artery 



Superior mesenteric artery 



Renal veins 



Inferior vena cava 



Middle colic 



Right colic 



Abdominal aorta 



Ileo-colic artery 

 Colic branch. 



Common iliac arterie: 

 Common iliac veins — .^ J- 



Appendicular artery 



Vermiform appendix 

 Middle hemorrhoidal 

 branches of 

 internal iliac 



Termination of 



ileum, cut 



Part of transverse 

 mesocolon 



Splenic artery. 



Parcreatica magna 



Inferior pancre- 

 atico-duodenal 

 artery 



Left kidney 



Inferior mesenteric artery 

 ■Left colic 

 Descending colon 

 -Sigmoid artery 



-Sigmoid flexure 



Superior hemorrhoidal artery 

 (on posterior surface of rectum) 



Anterior surface of rectum 



Superior and inferior mesenteric arteries; small intestine has been removed. 

 • 



left psoas muscle and, passing between the two layers of the sigmoid mesocolon, give off as- 

 cending and descending branches which anastomose with one another and with the left colic 

 and superior hemorrhoidal arteries, forming with them arches from which branches pass to the 

 sigmoid colon. 



(<:) The superior hemorrhoidal artery (a. haemorrhoidalis superior) is the terminal portion 

 of the inferior mesenteric. It descends into the pelvis lying between the folds of the mesentery 

 of the pelvic portion of the colon, and at the junction of the colon and rectum divides into two 

 branches which continue down the sides of the rectum, supplying that viscus and making anas- 

 tomoses with the middle hemorrhoidal from the internal iliac and with the inferior hemorrhoidal 

 from the internal pudic. 



