Plastic surgery involves the repair, reconstruction, or replacement of physical defects acquired at birth or by accident. This includes the skin, musculoskeletal system, hand, extremities, cranio and maxillofacial structures, breast, trunk and external genitalia. It makes use of aesthetic surgical principles not only to enhance undesirable qualities but in all reconstructive procedures as well. To reach this level of expertise much more training and experience is required, over being a general surgeon. A general surgeon will only be able to operate on more superficial levels and procedures that do not involve true reconstruction. General surgeons will only offer a small amount of cosmetic procedures based on the training they have had on that particular procedure.