APPLIED RADIOLOGICAL ANATOMY

Detailed explanation-1: -The middle and inferior rectal veins empty into the internal iliac vein and the inferior vena cava.

Detailed explanation-2: -The rectum has two drainage veins. The upper and middle thirds of the rectum drain primarily into the superior rectal vein and finally empty into the liver via the inferior mesenteric vein and portal vein. However, the lower third of the rectum drains into the middle rectal vein.

Detailed explanation-3: -The superior rectal vein (SRV) anastomoses with the middle and inferior rectal veins (IRV), which are, respectively, tributaries of the internal iliac and the pudendal veins.