Blood from the superior portion of the rectum normally drains into the superior rectal vein and via the inferior mesenteric vein to the liver as part of the portal venous system. Blood from the middle and inferior portions of the rectum is drained via the middle and inferior rectal veins. In portal hypertension, venous resistance is increased within the portal venous system; when the pressure in the portal venous system increases above that of the systemic, blood is shunted through the portosystemic anastomoses. The shunting of blood and consequential increase of pressure through the collateral veins causes the<unk> ities.
Anorectal varices
Anal fissure
Gastric varices
Anal fistula
Anal cancer
Genital ulcer
Anal wink
Perianal hematoma