Varicose veins are swollen, bluish veins that bulge above the skin's surface. True varicose veins are also tortuous (TOHR-chew-uhs), meaning they wind in a snake-like pattern. The twisting shape occurs because varicose veins not only expand in width, as a normal vein might do after exercise, but also increase in length. When the varicose vein becomes longer than the leg, it begins to wind back and forth. Varicose veins are no longer able to carry blood up the legs and return it to the heart. Most of the blood falls backward, or refluxes (REE-fluhk-suhz), perhaps due to weak vein walls that stretch or valves which don't close off properly. Some people may inherit this condition, while in others, it may develop because of injury or prolonged standing. Though it's difficult to prevent varicose veins, you may be able to discourage their formation by maintaining a normal weight and periodically sitting with your legs elevated. Regular exercise and avoiding tight elastic may also help. If you already have varicose veins, there are several treatment options if they're causing problems. If not, a doctor might advise a watch and wait approach. Only a few varicose veins will result in severe conditions like vein inflammation or leg ulcers.