varicose vein, superficial vessel that is abnormally lengthened, twisted, or dilated, seen most often on the legs and thighs. Varicose veins develop spontaneously, and are usually attributed to a hereditary weakness of the vein; the valves in the vein that keep the blood circulating upward toward the heart are usually incompetent. Increased pressure from long standing or exertion, or internal factors such as pregnancy, or lessened support by the tissues surrounding the veins that occurs with aging and obesity causes the weakened veins to dilate. Mild varicosities often cause no discomfort. Persons with more severe cases may develop swelling of the legs, ankles, and feet, and local eczema or ulcers. Mild varicosities may be treated with rest, elevation of the legs, and the use of elastic bandages or stockings. In severe cases surgical treatment may be necessary. Traditional surgery involves tying off and removing a vein segment. Varicose veins may now also be treated without removing them through an endoscopic surgical procedure that uses the heat produced by radio waves or a laser to seal off the veins. Varicose veins that occur around the rectum are called hemorrhoids, and those that form in the scrotum are called varicoceles.