Common iliac vein
Vena iliaca communis
Each common iliac vein forms in front of the sacroiliac joint, where the external and internal iliac veins join. The two common iliac veins unite at L5, just right of the midline, to form the inferior vena cava.
Overview
Because the IVC lies to the right of the midline, the two common iliac veins differ. The right common iliac vein is short and almost vertical. The left common iliac vein is longer and more oblique, and it passes behind the right common iliac artery. There the artery can press it against the body of L5. Only the left common iliac vein receives the median sacral vein. Neither vein has valves.
Anatomy
- Tributaries
The external and internal iliac veins (which form it), the iliolumbar veins, sometimes the lateral sacral veins, and the median sacral vein (left only).
Function
- Drain the lower limbs, pelvis and pelvic organs into the IVC.
Clinical significance
May–Thurner syndrome
In May–Thurner syndrome (iliac vein compression syndrome), the right common iliac artery compresses the left common iliac vein against L5. The constant compression scars the vein wall. This is one reason why deep vein thromboses of the iliac and femoral veins occur more often in the left leg. It is treated with venous stenting after the clot has been removed.
Compiled from standard anatomy and physiology references — see the Cardiovascular System sources. For education only; not medical advice.