If these valves are weak or destroyed, blood can circulation backward and pool during the veins, triggering the veins to stretch or twist. At times varicose veins appear to be cords in just the skin. Any vein may become varicose. But varicose veins are commonest inside the legs and toes https://www.sgvascularctr.com/what-surgery-is-available-for-varicose-veins/