In plastic surgery, excess tissue may be removed, or skin tissue from one part of the body may be added to another part where it is needed. When the skin is removed from one part of the body and grafted on to another part, usually only the top two layers are used. This is because the skin then has a better chance to "live" in its new location. New blood vessels form and circulation keeps the skin alive. When thicker layers of skin are grafted, as when someone has had a bad accident or severe burn, the chances of the new skin living are not as good. When it does, however, it is likely to look more natural.