May-Thurner syndrome

May-Thurner syndrome is deep vein thrombosis of the iliofemoral vein due to compression of the left common iliac vein by overlying right common iliac artery.

In contrast to the right common iliac vein, which ascends almost vertically to the inferior vena cava, the left common iliac vein takes a more transverse course. Along this course, it underlies the right common iliac artery, which may compress it against the lumbar spine.