Question

Superior rectal vein drains into?

• A. Inferior mesenteric vein
• B. External iliac vein
• C. Internal iliac vein
• D. Internal pudendal vein

Hint:

The superior rectal vein is the portal limb of the anorectal anastomosis.

Answer 1

The Correct Option is A

Step 1: The rectum has a portosystemic anastomosis. The upper part drains via the superior rectal vein, while the middle and lower parts drain via the middle and inferior rectal veins.

Step 2: The superior rectal vein drains into the inferior mesenteric vein, which belongs to the PORTAL venous system. This makes it the site of portosystemic anastomosis at the anorectal junction.

Step 3: The inferior rectal vein drains into the internal pudendal vein, and the middle rectal vein drains into the internal iliac vein - both of these belong to the SYSTEMIC (caval) system.

Step 4: Therefore the superior rectal vein drains into the inferior mesenteric vein, option (a). The external iliac vein has no role here.