Fossa Ovalis

Greater Saphenous Vein

The union of the dorsal vein of the great toe and the dorsal venous arch of the foot forms the Greater Saphenous vein. It ascends anterior to the medial malleolus, passes posterior to the medial condyle of the femur, anastomoses with the small saphenous vein, transverses the saphenous opening (Fossa Ovalis) in the fascia lata, and then enters into the femoral vein. It drains the skin and the superficial fascia of the medial foot and let, the skin and superficial fascia of most of the thigh, the lower abdominal wall, and the perineal region. This vein has ten to twelve valves, which are usually located inferior to the perforating veins. This prevents reflux of the blood distally and allows the blood to overcome the force of gravity as it passes to the heart.

This vein is frequently used as graft material in coronary bypass surgery because it is readily accessible, sufficient distance occurs between the tributaries and perforating veins so that usable lengths can be harvested, and its wall contains a higher percentage of muscular and elastic fibers than other superficial veins. To be used, the vein is reversed so that the valves do not obstruct blood flow in the graft. Removal of this vein rarely produces a significant change in circulation effectiveness.