Varicose veins are veins on the leg which are large, twisted, and ropelike, and can cause pain, swelling, or itching.
They are an extreme form of telangiectasia, or spider veins.
They occur in 25-30% of the western population.
Male and females are equally affected. 1 in 8 teenagers develop early signs of "leaking valves".
Varicose veins result due to insufficiency of the valves in the communicating veins.
These are veins which link the superficial and deep veins of the lower limb.
Normally, blood flows from the superficial to the deep veins, facilitating return of blood to the heart.
However, when the valve becomes defective, blood is forced into the superficial veins by the action of the muscle pump (which normally aids return of blood to the heart by compressing the deep veins).