Varicose veins, are swollen, gnarled, tangled, twisted, enlarged and discolored veins. They are easily visible through the skin.
A healthy vein allows blood to flow in one direction through one-way valves. A varicose vein is caused when one or more of these valves weaken and allow blood to flow backwards, or pool. The walls of the veins become stretched, losing elasticity as the blood accumulates. The appearance of the veins becomes enlarged and bulge due to trapped blood.
The furthest veins from the heart are often the most susceptible. Because gravity and weight make it more difficult for blood to flow back to the heart, varicose veins are most common in the legs.