Insufficiency

Impaired function, weak function, or loss of function. Venous insufficiency occurs when the valves in the veins are incompetent (leaky) – that is to say, they no longer close tightly and not all the venous blood is directed solely towards the heart. Blood refluxes through the incompetent valves and pools in the legs, causing the affected veins to dilate (balloon out). Varicose veins develop.