Saphenous Vein

What is the saphenous vein?

The saphenous vein is a large superficial vein located in the leg. It starts at the groin and extends all the way to the ankle. This is called the greater saphenous vein. There is another slightly smaller vein and it starts just behind the knee and runs to the ankle. This is called the lesser saphenous vein.

In the groin the greater saphenous vein joins the major vein (femoral vein) of the leg which goes to the heart.

The saphenous vein drains blood from the superficial tissues of the leg to the groin. From the groin, the saphenous vein enters the deeper circulation and transfers blood to the femoral vein. This junction at the groin (saphenofemoral junction) is the cause of more than 90% of varicose veins. Any pressure in the groin can easily traumatize the valves in the saphenous vein at the junction and can lead to obstruction of the vein. When the vein is obstructed at the groin, it creates a back flow of blood, which leads to pooling of the blood in the leg. A classic example of a condition which does this is pregnancy.

Does the saphenous vein have branches?

Yes, the saphenous vein has numerous branches along its entire length. In the lower leg the smaller branches of the saphenous vein (collaterals) join the deep vein in the leg. When the blood starts to pool in the saphenous vein, the pressure is easily transferred to the branches, which then appear as bulging discs (varicosities).



What are important features of the saphenous vein?

The size of the saphenous is very variable in different individuals. Some have a large saphenous vein and others have a small saphenous vein. In some individuals the saphenous vein runs along the entire length of the leg. In others it divides at the groin and one branch runs on top of the thigh and the other runs on the side of the thigh. Both of these branches can be affected and become varicosed.



Does the saphenous vein have valves?

Yes, valves are "one way door-like" structures and do exist in the saphenous vein. The valves permit blood to flow one-way and close off to prevent blood from going in a reverse fashion. When these valves are damaged or defective, pooling of blood does result in the legs.

What is saphenous vein useful for?

The saphenous vein is important for:

IV cannulation: In some individuals (particularly infants, elderly and those involved in trauma); there are no veins in the arm for IV access. In these individuals, the IV is placed in the saphenous vein. The IV may be placed near the ankle or in the groin. This can be life saving in individuals with no other IV access.

Cardiac bypass: The saphenous vein is one of the most important veins for open heart surgery. It is used in more than 90% of all bypass surgeries. Without the saphenous vein, open heart surgery would indeed be very difficult.

Vascular surgery: The saphenous vein is the most important vein used by vascular surgeons for bypass. It is better than any plastic or prosthetic graft. It is very useful for bypass in the legs and arms. The saphenous vein is an excellent graft for almost every type of vascular procedure.

What disorders are associated with saphenous veins?

Varicose veins: Without the saphenous vein, there would be no varicosities in the leg. Varicose veins occur in the saphenous vein more than any other vein in the body. The saphenous vein is very superficial and prone to injury. It is also very thinned walled and does not tolerate high pressures. Any condition that causes high pressures in the vein can lead to varicose veins. Varicose veins of both the lesser and greater saphenous veins are common. The varicose veins of the greater saphenous are typically seen on the inside of the thigh and lower leg. When the lesser saphenous vein is involved, the varicosities are seen at the back of the lower leg.

Phlebitis: Anytime a blood clot occurs in a vein, it can initiate an inflammatory reaction known as phlebitis. Phlebitis of the saphenous vein is extremely common. The condition is benign and usually resolves within a few weeks.



Final Point

The saphenous vein is involved in 99% of all the varicose veins seen in females. It is a fragile vein and easily traumatized. Any condition that causes high pressures in this vein causes the valves to pull apart and leads to engorgement of the saphenous vein. This is what we call a varicose vein. In time, the blood is unable to move along the vein and remains static; leading to formation of blood clots and phlebitis. As the condition progresses, the pooled blood collects in the branches of the saphenous vein and leads to development of varicosities.