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The leg vein pump
In normal life, ALL of the valves
in all of the veins of the leg work normally AND the leg is able to move normally.
Moving normally means that the ankle,
knee and hip joints are all working and the nerves and muscles are
functioning properly, so that the patient can walk normally.
Anything stopping normal movement,
particularly walking, stops the leg pump from working.
When the movement is normal and the valves are
all working, the blood is pumped up both deep and superficial veins during muscles contraction.
Such muscle contraction happens when the foot pushes downwards against the
floor during walking. This is demonstrated in the animated diagram then
the leg is PUMPING. When the leg RELAXES,
such as when i is being swung forwards to take the next step and all of
the weight is on the other leg, the pumping stops and the blood starts to flow
backwards down both deep and superficial vein systems. This backflow is
due to gravity acting on the blood.
This back-flow of blood causes the
valves to snap shut, stopping the blood from flowing back down the
leg, making sure the circulation is a one-way system.
This is how the leg vein pump works
normally.
Now we will look at what happens to the leg when the valves fail. |
