Venous insufficiency involves one or more veins.
The valves in the veins usually channel the flow of blood toward the heart. When these valves are damaged, blood leaks and pools in the legs and feet. Chronic venous insufficiency is a prolonged condition of incompetent venous circulation. It occurs because of partial vein blockage or venous valve leakage. Chronic venous insufficiency can cause discoloration of the skin of the ankles in addition to the above symptoms.