A burn injury is essentially an injury to the epidermal and dermal layers of the skin. While the epidermis is rapidly and efficiently repaired in humans, the dermis heals poorly if at all. In burns where most of the dermis is not injured (superficial partial thickness burns), the burn heals rapidly with a cosmetically and functionally acceptable scar. In burns where most or all of the dermis is dead (deep partial thickness or full thickness burns), healing is slow (if at all) and the scarring is severe.

Skin grafting for burns consists of repairing the damaged area of skin by harvesting the top layers of an area of uninjured skin. Top layers of undamaged skin are removed with an instrument called a dermatome. This intervention creates an area of exposed dermis called the donor site. The burned skin is debrided by serially slicing off layers of dead dermis until live tissue is reached in a process called tangential excision. The cutting is parallel (tangential) to the surface of the burn. Tissue bleeding and appearance is used as a sign of viability. The harvested skin is attached (using staples, sutures, or glue) to the excised wound bed; it becomes vascularized over the next 3–5 days. The donor site heals by epithelialization from the hair follicles and sweat glands deep in the remaining dermis.