The internal iliac vein (latin: vena iliaca interna) is a large blood vessel formed by several veins above the greater sciatic foramen.
The internal iliac vein arises at the level of the greater sciatic foramen, runs behind the internal iliac artery, collecting the visceral and parietal tributaries from the pelvic cavity. The internal iliac vein ascends along the lateral wall of the pelvis, reaches the linea terminalis and at the level of the sacroiliac joint joins the external iliac vein, forming the common iliac vein.
On its way, the internal iliac vein collects the following veins: the gluteal, internal pudendal, obturator, lateral sacral, middle rectal, vesical, uterine and vaginal veins.
The internal iliac vein collect venous blood from the pelvic viscera, the walls of the pelvis, the gluteal region and the perineum.