Varicose veins are veins beneath the skin of the legs, which are expanded, blocked and twisted. They are very common and do not cause medical problems in most people. There are two main systems of veins in the legs:
The leg muscles firmly press the deep veins during walking, carrying most of the blood back up the legs to the heart.
These occur below the skin which can form varicose veins.All of these veins are one-way valves to ensure that the blood flows towards the heart. Failure of these valves allows blood to flow backwards down the veins and results in pressure and pain when standing. This excess pressure leads to expansion of the veins so that they do not close properly. Blood then flows towards the legs along these veins and causes varicose veins to develop. High pressure in these veins also is the reason for the development of spider veins and discoloured areas which look like bruises.