The great saphenous vein (also known as long saphenous vein, latin: vena saphena magna) is a large superficial, subcutaneous vein of the leg.
The great saphenous vein originates from the union of the dorsal vein of the great toe and dorsal venous network of the foot, more precisely, from the medial marginal vein. The great saphenous vein ascends along the medial side of the lower leg together with the saphenous nerve. Later it runs to the medial side of the anterior region of the thigh to reach the saphenous opening, then pierces the cribriform fascia and joins with the femoral vein.
The main tributaries of the great saphenous vein in the thigh region are: the superficial epigastric vein, the superficial iliac circumflex vein, the external pudendal veins and the accessory saphenous vein.
The great saphenous vein collects deoxygenated (venous) blood from the medial side of the foot, as well as the medial and anterior side of the lower leg.