Veins that supply the pelvis are – internal iliac, superior rectal, median sacral and ovarian veins, and pelvic venous plexuses.
The internal iliac vein runs upward lateral to the internal iliac artery and joins the external iliac vein to form the common iliac vein. Its tributaries correspond to the branches of the internal iliac artery except umbilical and lumbar veins which drain, respectively, into the portal and common iliac veins.
Note that the superior gluteal vein is the largest tributary of the internal iliac vein except during pregnancy when the uterine veins exceed its size greatly.
The median sacral veins accompany the median sacral artery and terminate in the left common iliac vein.
The ovarian vein forms just below the pelvic inlet by the condensation of the pampiniform plexus around the ovarian artery.
On the right side it drains into the inferior vena cava and on the left side into the left renal vein.