Definition of Varicose veins:

Varicose veins are swollen, twisted, painful veins that have filled with an abnormal collection of blood.

Causes, incidence, and risk factors:

In normal veins, valves in the vein keep blood moving forward toward the heart. With varicose veins, the valves do not function properly, allowing blood to remain in the vein. Pooling of blood in a vein causes it to enlarge.

This process usually occurs in the veins of the legs, although it may occur elsewhere. Varicose veins are common, affecting mostly women.

Causes include congenitally defective valves, thrombophlebitis, and pregnancy. Prolonged standing and increased pressure within the abdomen may increase susceptibility to the development of varicose veins or aggravate the condition.

Primary varicose veins occur because of congenitally defective valves, or without a known cause. Secondary varicose veins occur because of another condition, such as occurs when a pregnant woman develops varicose veins.