Normal Veins: HowThey Work

When standing, blood flows to the legs due to the pumping action of the heart and the force of gravity. In order for blood to return back to the heart, against the force of gravity, there must be a pumping mechanism in the legs.



This leg pump is made up of:

 

1. Muscle movement of the legs
2. Valves in the veins of the legs
    

In a normal person the ‘pumping’ action is generated through movement of the muscles in the legs. The blood is literally ‘squashed’ against the valves inside the veins which open in the direction of the heart.

When the muscle movement stops, the valves close shut preventing the blood from flowing back down the vein.

The prevention of this back flow by the valves is the key to how veins maintain blood flow back towards the heart. When the valves are working the vein is said to be competent.