heart and blood vessel disorders
Varicose Veins
Causes of Varicose Veins
The precise cause of varicose veins is unknown, but the main problem is probably a weakness in the walls of superficial veins (veins located just under the skin). This weakness may be inherited. Over time, the weakness causes the veins to lose their elasticity. Veins stretch and become longer and wider. To fit in the same space that they occupied before they stretched, the elongated veins become convoluted. They may appear as a snakelike bulge beneath the skin. Women may be more likely to develop varicose veins than men, and their initial occurrence may be during pregnancy. In addition, the following can contribute to the development of varicose veins in predisposed people: Prolonged standing Obesity Increasing age Arteries carry blood with oxygen and nutrients away from the heart to the rest of the body. Veins return blood to the heart from the rest of the body. Valves in the veins keep blood flowing upward toward the heart and stop the blood from flowing backward. In people with varicose veins, the widening of the veins causes the valve flaps (cusps or leaflets) to separate. When the person stands, the blood is pulled backward by gravity and is not stopped because the valve flaps are separated. Thus, blood flows backward, rapidly filling the veins and causing the thin-walled, convoluted veins to enlarge even more. Some of the connecting veins, which normally allow blood to flow only from the superficial veins into the deep veins, also enlarge. If they enlarge, their valve flaps also separate. Consequently, blood flows backward into the superficial veins when the muscles squeeze the deep veins, causing the superficial veins to stretch further. Many people with varicose veins also have Spider Veins , which are enlarged capillaries. 