How Does Vein Disease Occur?

Veins are blood vessels that return blood to the heart from the body.  To counter the effects of gravity, the veins contain one-way valves which open to allow blood to flow to the heart and close to prevent the backflow of blood to the body.  When the valves do not function properly or if the vein is damaged and prevents the valves from closing, blood can begin to collect in the vein and cause a variety of vein complications.