The heart pumps blood, with oxygen and nutrients, through the arteries to all the cells in the body. The veins bring the blood back to the heart to be recirculated. Because when you sit or stand, your legs are lower than the rest of body, leg veins have to work against gravity. The leg veins have one way valves that, when functioning properly, allow the blood to flow from the lower leg to the upper leg. There are two systems of veins in your leg, deep veins, and superficial veins. The deep veins are beneath the muscle, they are more critical for circulation, because 90 percent of the blood return, from the legs to the heart, flows through the deep veins. The superficial veins are above the muscle, these are responsible for 10% of the blood returning to the heart, from the legs. These valves also allow the blood to flow from the superficial veins to the deep veins, through veins called perforator veins. Perforator veins provide a path, allowing one-way flow, from the superficial veins, to the deep veins.
Names of Veins: Deep Veins, Femoral vein, Popliteal vein
The femoral vein is the deep vein, in the thigh, which empties the blood from the leg veins. The popliteal vein is the deep vein behind the knee, which empties the blood from the veins below the knee in the back of the calf, into the femoral vein. It is located beneath the muscles and behind the knee, where the knee bends.
Superficial veins: Greater Saphenous Vein, Lesser Saphenous Vein
These veins exist either near the surface or beneath the surface but above the muscle. Just because a vein is beneath the surface, it isn’t necessarily a deep vein. A vein can still be a superficial vein, if it is beneath the surface but above the muscle.
The Greater Saphenous Vein is a superficial vein. It originates near the ankle and extends up the leg and empties into the femoral vein. There is also a lesser saphenous vein, which is a superficial vein and lies in the posterior calf. It extends up the back of the calf and empties into the popliteal vein, the deep vein beneath the muscles under the crease behind the knee.
The heart is the pump for the arteries, to bring blood to the legs. The pump for the leg veins to bring back to the heart are the muscles in the calf. As a person walks, the calf muscles contracts. This squeezes the vein and propels the blood in the leg, because the valves in the veins only allow blood to flow one way.