[3] The left external iliac vein remains medial to the artery along its whole path.

The right external iliac vein is medial to the artery, but as it ascends, it runs posterior to it.

Although less common than May-Thurner syndrome, it is being progressively documented due to modern imaging methods.

Compression of the left external iliac vein by the right common iliac artery or left hypogastric artery can occur as it crosses over the vein into the pelvis.

[5] Failure to develop or agenesis of the external iliac vein has been described in association with Klippel–Trenaunay syndrome.