Varicose veins are abnormally enlarged (more than 3mm while standing), tortuous, superficial veins. They occur most commonly in the lower legs but can occur anywhere. They are part of a spectrum of chronic venous disorders of the lower leg.

Varicose veins are very common and can occur in up to 30% of the population. The exact cause of varicose veins is unknown. A number of factors including abnormalities of the vein wall, inflammation and increased pressure in the vein play a role. Increased pressure is mostly due to malfunction of the valves and reflux, inadequate calf muscle pump function and occasionally due to proximal obstruction due to thrombosis or compression by a tumour or major artery.