The blood vessels of the rectum and anus, showing the distribution and anastomosis on the posterior surface near the termination of the gut. (Labeled as hemorrhoidal artery.)
In males, the middle rectal artery may give off branches to the prostate and the seminal vesicles, while in females it gives off branches to the vagina.
Additional images
Sigmoid colon and rectum, showing distribution of branches of inferior mesenteric artery and their anastomoses.