Spider veins and varicose veins are a common disease
You will find detailed information in our vein dictionary
Connective tissue structure in the veins. When the leg veins transport oxygen-depleted blood back to the heart, they have to work against gravity. The veins contain valves to make sure that the blood flows in the right direction. The valves open when blood flows through towards the heart, but close when it starts to flow in the wrong way.
Therefore, the valves make sure that the blood can flow in only one direction – and that is towards the heart. With varicose veins or chronic venous insufficiency (CVI), the valves no longer function properly and are unable to close tightly (incompetent valves). Blood sometimes flows in the wrong direction back down the legs and pools in the veins there. Left untreated, it causes irreversible damage to the veins with subsequent complications.