What does the Great Saphenous Vein do?
As with all veins, the function of the Great Saphenous Vein (GSV) is to return venous blood to the heart. Arterial blood contains nutrients and oxygen which are supplied to all living tissues in the body. When the tissues have metabolised the oxygen and nutrients, they produce waste products such as carbon dioxide, water and other waste products like urea. These waste products need to be removed from the healthy tissue and it is the venous blood that carries them away.
The venous blood takes these waste products to the lungs where the carbon dioxide is breathed out and to the kidneys where the urea and other wastes are excreted.
The Great Saphenous Vein (GSV) is the main truncal vein of the lower leg and, as such, drains blood from the inner part of the foot, the skin and fat of the front and inner aspect of the lower leg, and the skin and fat of the inner part of the thigh. The Small Saphenous Vein (SSV) drains venous blood from the outer side of the foot, the skin and fat of the back and outside of the lower leg but as it connects with the deep vein (popliteal vein) at the back of the knee, it has no function of venous drainage in the thigh.
Therefore venous blood from the skin and fat of the front and outside of the thigh is drained by another vein called the Anterior Accessory Saphenous Vein (AASV) which joins the Great Saphenous Vein (GSV) at the groin and the posterior (is this inner or outer?) part of the thigh is drained by the Posterior Accessory Saphenous Vein (PASV) which also drains into the Great Saphenous Vein (GSV).
The tributaries drain blood into the Great Saphenous Vein (GSV) which then pumps the blood up this venous trunk and into the deep system at the groin. The junction of the Great Saphenous Vein (GSV) and the deep vein it feeds into, the Common Femoral Vein (CFV), is very important in varicose vein surgery and is called the Sapheno-Femoral Junction (SFJ).