middle rectal artery middle rectal artery the middle rectal artery is an artery in the pelvis that supplies blood to the rectum. middle rectal arterythe 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.)the arteries of the pelvis.detailssourceinternal iliac arteryveinmiddle rectal veinssuppliesrectum, seminal vesicle, vaginaidentifierslatinarteria rectalis media, arteria haemorrhoidalis mediata98a12.2.15.036ta24338fma18826anatomical terminology structure internal iliac artery, showing branches, including middle rectal artery the middle rectal artery usually arises from the internal iliac artery. it is distributed to the rectum above the pectinate line. it anastomoses with the inferior vesical artery, superior rectal artery, and inferior rectal artery. in males, the middle rectal artery may give off branches to the prostate and the seminal vesicles. in females, the middle rectal artery gives off branches to the vagina. function the middle rectal artery supplies the rectum above the pectinate line. additional images sigmoid colon and rectum, showing distribution of branches of inferior mesenteric artery and their anastomoses. middle rectal artery