Veins of rectum and Anal canal Anterior view Inferior vena cava Inferior mesenteric vein (to portal vein via splenic Common iliac veins Rectosigmoid vein Mddle sacral vein Intemal iliac vein Extemal iliac vein Superior rectal vein(bifurcation)- Obturator vein Communication between Superior vesical and uterine veins intemal and perimuscular rectal plexuses Mddle rectal vein Intemal pudendal Perimuscular rectal plexus Vaginal vein Intemal rectal plexu Inferor vesical vein Communication between Intemal pudendal vein in intemal and extemal udendal ( Alcock's) canal venous plexuses Etemal rectal plexus Inferior rectal vein