While Flap Surgery is fairly similar to a skin graft, they have utter differences. In skin grafts, only the top two layers of skin are used, however, in flap surgery for wounds, a blood supply is left intact when moved from the donor site. This procudure is most often used in plastic or reconstructive surgery. Some of the most common uses include amputation of a limb, or in severe trauma such as jaw reconstruction, or breast reconstruction following a mastectomy. In these situations, and many others, the areas are too large for use of a skin graft. By using a flap, it allows the wound to close more quickly, and prevents introduction of bacteria and germs that may lead to infection. In addition, it provides more precise filling of the areas requiring coverage. Finally, not only does a flap promote quicker healing, but it also protects the underlying tissue, such as bones, nerves, cartilage etc., and may even improve function of the affected area.