External iliac vein

At a glance

English

External iliac vein

Latin (TA2)

Vena iliaca externa

System

Vein

Region

Trunk

Side

Paired, left and right

About the external iliac vein

The external iliac vein carries blood from the lower limb into the abdomen. It begins behind the inguinal ligament as the upward continuation of the femoral vein and follows the pelvic brim upwards and backwards. In front of the sacroiliac joint it meets the internal iliac vein, and the two together form the common iliac vein. Along its whole length it keeps close company with the external iliac artery.

Its position relative to that artery differs a little between sides. On the left the vein stays on the medial side of the artery all the way. On the right it starts medial to the artery and, as it climbs, slips round to lie behind it. Psoas major lies lateral to the vein except where the artery comes between them. The vein is crossed on its way by the ureter and by the internal iliac artery as they head towards the midline; in women the ovarian vessels and the round ligament also cross it, and in men the ductus deferens. It may have a single valve, though often there is none.

Its main tributaries arise just above the inguinal ligament: the inferior epigastric vein, which ascends in the anterior abdominal wall, and the deep iliac circumflex vein, which follows the iliac crest. A pubic vein linking it with the obturator vein is also common.

Like the common iliac vein, the external iliac vein can be squeezed where an artery crosses it. On the left, the internal iliac artery or the right common iliac artery may press on it as they pass into the pelvis, and the right vein can be affected in a similar way. These compressions are less common than the classic May-Thurner pattern but are increasingly seen on modern scans, and they can favour deep venous thrombosis. Absence or underdevelopment of the vein has been reported with Klippel-Trenaunay syndrome. The vein also serves as an access route for catheters and filters passed up from the groin.

Course and drainage

Begins at

Continues the femoral vein behind the inguinal ligament.

Drains into

Joins the internal iliac vein in front of the sacroiliac joint to form the common iliac vein.

Drains

Drains the lower limb, via the femoral vein, together with the lower anterior abdominal wall through the inferior epigastric and deep circumflex iliac veins.