The great saphenous vein is the major superficial vein of the medial leg and thigh. It is the longest vein in the human body, extending from the top of the foot to the upper thigh and groin. The great saphenous vein plays an important role in returning blood from the superficial tissues of the leg to the heart and is also used in several medical procedures due to its size and superficial location.
The great saphenous vein is a superficial vein that runs through the subcutaneous tissue layer deep to the dermis and superficial to the skeletal muscles of the foot and leg. It begins at the dorsal venous arch of the foot, a major superficial vein that drains blood from the toes and back of the foot. From the dorsal venous arch, the great saphenous vein passes anterior to the medial malleolus of the ankle and enters the medial side of the leg. As it ascends through the leg, it merges with many superficial veins of the leg before passing over the medial epicondyle of the femur at the knee and entering the thigh. Continuing through the thigh, the great saphenous vein turns anteriorly while merging with several more superficial veins. At the top of the thigh, it passes through the saphenous opening of the fascia lata and enters the deeper tissues of the upper thigh before merging into the femoral vein.
An extensive network of superficial veins connects to the great saphenous vein throughout its length. These veins collectively drain the superficial structures of the foot, medial leg, medial thigh, groin, and pelvic region. Many one-way venous valves help to move blood through the veins of the lower extremities against the pull of gravity. Blood passing through the veins of the leg is under very little pressure and so must be pumped toward the heart by the contraction of skeletal muscles in the leg. Venous valves help to trap blood between muscle contractions and prevent it from being pulled back down towards the feet by gravity.
The great saphenous vein is clinically significant for its use in coronary bypass surgery and in intravenous delivery of fluids. Because of its superficial location and the redundancy of veins in the leg, it can be harvested as a venous graft for coronary bypass surgery. During this surgery, the great saphenous vein is removed from the leg and sutured from the aorta to a coronary artery to bypass a blockage in the artery. The vein is either turned so that its venous valves permit proper blood flow or its valves are removed prior to being sutured in place. Another use for the great saphenous vein is in emergency cases where a patient is in shock and has suffered the collapse of more commonly used veins. In this case the great saphenous vein can be used to deliver fluids and blood to replenish the body.