The superficial veins of the lower limb contain unidirectional valves to enable the return of blood to the deep system towards the heart against gravity. These valves are bicuspid and are found at various locations along the veins. There are on average 6 valves in the GSV, more located below the knee than above with the most proximal valve located 2-3 cm below the SFJ. In the SSV the valves are closer together and located more evenly along the vein. The deep venous system of the leg also contains valves, with more located distally than proximally. The most proximal valve in the Femoral vein lies just below the SFJ. Major perforating veins have 1-3 valves, usually located below the level of the fascia with valves that direct blood towards the deep veins. Small perforating veins are valveless[8].
