Variant formation of left common iliac vein by the confluence of four veins.

Common iliac vein variations are relatively rare compared to the variations of external and internal iliac veins. A rare pattern of formation of common iliac vein by the confluence of four veins is being reported here. The left common iliac vein was formed by the union of left external iliac vein, internal iliac vein, iliolumbar vein and a common trunk formed by the obturator and vesical veins. External iliac vein and obturator veins were connected by a communicating vein. Both external and common iliac veins were respectively medial to the external and common iliac arteries. Knowledge of this variant formation of common iliac vein could be useful to radiologists, gynecologists and orthopedic surgeons.