THE 8l'Pn.\UKXAL ARTERIES. 



615 



sigmoid flexure of the colon, and divides into branches which supply that part of 

 the intestine, anastomosing above with the colica sinistra, and below with the 

 superior hteniorrhoidal artery. This vessel is sometimes replaced by three or four 

 small branches. 



The superior haemorrhoidal artery, the continuation of the inferior mesenteric, 

 descends into the pelvis between the layers of the meso-rectum, crossing, in its 



Middle 7we 

 Inferior hxmorrhoidaL' 



TIG. 371. The inferior mesenteric and its branches. 



course, the ureter and left common iliac vessels. It divides into two branches, 

 which descend one on each side of the rectum, and about five inches from the anus 

 break up into several small branches, which are distributed between the mucous 

 and muscular coats of that tube, nearly as far as its lower end, anastomosing 

 with each other, with the middle haemorrhoidal arteries, branches of the internal 

 iliac, and with the inferior haemorrhoidal branches of the internal pudic. 



The Suprarenal Arteries. 



The suprarenal arteries ( Fig. 367) (middle suprarenal) are two small vessels 

 which arise, one on each side of the aorta, opposite the superior mesenteric artery. 

 They pass obliquely upward and outward, over the crura of the Diaphragm, to 

 the under surface of the suprarenal capsules, to which they are distributed, anasto- 

 mosing with capsular branches from the phrenic and renal arteries. In the adult 

 these arteries are of small size ; in the foetus they are as large as the renal arteries. 



