436 SPLANCHNOLOGY, OR ANATOMY OF THE VISCERA 



The cul-de-sac of Douglas (rectovaginal pouch) is the space in 

 front of the rectum and behind the cervix and upper fourth 

 of the vagina. It is formed by the peritoneum reflected over 

 the rectum to the vagina and uterus. In the male it is the 

 space formed between the rectum and bladder, and is called 

 the, rectovesical space, or pouch. 



The Arteries to the Colon. The ascending colon by the right 

 colic; the hepatic flexure, by the branches of the anastomosing 

 loop formed by the right and middle colic; the transverse colon, 

 by the branches of the anastomosing right, middle, and left 

 colic arteries; the splenic flexure, by the branches derived 

 from the anastomosing loop of the middle and left colic; the 

 descending colon is supplied by branches from the left colic; 

 the sigmoid flexure, by the sigmoid artery. The right and 

 middle colic arteries are derived from the superior mesenteric, 

 the left and sigmoid branches are from the inferior mesenteric 

 artery. The arteries to the rectum are the superior liemor- 

 rhoidal, a branch of the inferior mesenteric; the middle hemor- 

 rhoidal, a branch of the anterior division of the internal iliac, 

 and the inferior hemorrhoidal, from the internal pudic. 



The veins of the large intestines correspond to the arteries 

 and open into the portal vein, through the superior and inferior 

 mesenteric veins; the former joins with the splenic to form 

 the portal, the latter opens into the splenic vein. Veins of the 

 rectum drain, into the inferior mesenteric, by the superior 

 hemorrhoidal vein, the middle hemorrhoidal, into the internal 

 iliac, and the inferior hemorrhoidal into the internal pudic. 

 These veins form the hemorrhoidal plexus, which communi- 

 cates with the portal and systemic circulations, the former 

 by means of the inferior mesenteric, receiving the superior 

 hemorrhoidal, and the latter the middle and inferior hemor- 

 rhoidal opening into the internal iliac, and internal pudic 

 veins respectively. 



The lymphatics of the cecum, ascending and transverse 

 colon drain into the mesenteric nodes; the descending colon 

 and sigmoid flexure into the lumbar nodes. The rectal and 

 anal lymphatics drain into the preaortic nodes. The skin 

 around the margin of the anus is drained by the radicles which 

 pass into the superficial inguinal nodes. 



The nerves of the large bowel and rectum are derived from 

 the sympathetic system, the former through the superior 



