VARICOSE VEINS

Normal venous system made up of two systems deep veins and superficial veins . These system are connected with perforators at various levels in thigh, around knee and legs. Both deep and superficial veins connected above thigh to form a single venous drainage system , at their junction there is a sapheno-femoral junction(SFJ) with a competent valve for unidirectional flow of the blood.

Ref Fig.  Blausen.com staff (29 August 2014). "Medical gallery of Blausen Medical 2014". 

Varicose veins disease occurs due to the chronic venous insufficiency due to one of the or combination of the 1. Incompetent SFJ , damage to the valve, 2. Incompetent Perforators or 3. Weakness of the vein due the damage to the venous valves. Varicose veins are the dilated tortuous veins. 

The most severe complication of the long standing varicose veins is non healing venous ulcer. Bleeding can occur from long standing. Venous ulcer are difficult to treat, but can be treated with best successful result with simultaneous treatment of the varicose veins.