What is a "great saphenous vein"?

A great saphenous vein is a major vein located in the lower extremities of the human body. It starts from the foot, runs along the inner side of the leg, and extends up to the groin area. It plays a vital role in venous circulation by carrying deoxygenated blood from the superficial tissues of the leg back to the deep veins. The great saphenous vein is often visible beneath the skin and can sometimes become varicose, causing swelling and discomfort.