The circulatory system consists of veins and arteries. Arteries are blood vessels that bring the fresh oxygenated blood full of nutrients from the heart to the rest of the body. Veins are vessels that transport blood without oxygen and nutrients back to the heart against gravity. In healthy leg veins, one-way valves allow blood to move only in one direction: upstream towards the heart. In order to do this, when you walk, your leg muscles squeeze the deep veins of your legs and feet pushing the non-oxygenated blood back to the heart. In your veins there are one-way valves that are placed about one inch apart that keep blood flowing in the right direction. When your leg muscles relax, the valves inside your veins close preventing the backward flow of blood back down the legs.
There are three types of veins in your legs: superficial veins, which lie close to the skin, deep veins, which lie in or beneath the muscles, and perforating veins, which connect the superficial to the deep veins. Deep veins bring the blood back to the major vein in your abdomen called the vena cava, which brings the blood straight to the heart.
Causes of Vein Disease
When a valve fails to function, the blood can begin to pool in your legs and cause a variety of health problems including swollen ankles, blood clots, leg pain, spider veins, varicose veins, and even ulcers. When your leg veins cannot bring enough blood back to the heart, the blood stays in your legs, causing various problems due to venous blood stasis.
If the blood does not move through deep veins, a condition called deep venous thrombosis may arise. If the valves in the superficial system of veins are not working properly, the condition is called superficial venous insufficiency.