Definition of Saphenous vein

Saphenous vein: The saphenous veins -- there are two, the great and the small saphenous veins - serve as the principal veins running superficially (near the surface) up the leg.

The great saphenous vein (also called the large saphenous vein) goes from the foot all the way up to the saphenous opening, an oval aperture in the broad fascia of the thigh, a fibrous membrane through which the vein passes.

The small saphenous vein runs behind the outer malleolus (the protuberance on the outside of the ankle joint), comes up the back of the leg and joins the popliteal vein in the space behind the knee (the popliteal space).