MODEL RELEASED. Varicose vein surgery. Close-up of a surgical tool being used in an operation to remove varicose veins from a patient's legs. The varicose vein has been dissected from the surrounding tissue, and is now being pulled out of the leg by the surgeon's hand and a pair of forceps. Varicose veins form due to defective valves in veins, usually those of the legs. As blood is circulated around the legs, these valves prevent it from sinking to the feet. As the valves stop working, blood pools downwards, distending the veins. Surgical removal is carried out in severe cases, allowing the blood to flow through other veins instead. Photographed in the UK.