What is "common iliac vein"

n. formed by the internal and external iliac veins; unites with its fellow from the opposite side of the body to form the inferior vena cava

In human anatomy, the common iliac veins are formed by the external iliac veins and internal iliac veins. The left and right common iliac veins come together in the abdomen at the level of the fifth lumbar vertebra, forming the inferior vena cava. They drain blood from the pelvis and lower limbs.

Both common iliac veins are accompanied along their course by common iliac arteries.