Wound healing
![Approximate times of the different phases of wound healing,[10] with faded intervals marking substantial variation, depending mainly on wound size and healing conditions, but image does not include major impairments that cause chronic wounds.](/Images/godic/202501/11/Wound_healing_phases5045.png")
![A fluorescence micrograph of cells in Drosophila larvae healing after a puncture wound. The arrow points to cells that have fused to form syncytia, and the arrowheads point to cells that are oriented to face the wound.[14]](/Images/godic/202501/11/Fluorescent_wound_healing5045.jpg")
![A scab covering a healing wound](/Images/godic/202501/11/Scab5046.jpg")
Wound healing is the process by which skin or other body tissue repairs itself after trauma. In undamaged skin, the epidermis (surface layer) and dermis (deeper layer) form a protective barrier against the external environment. When the barrier is broken, an orchestrated cascade of biochemical events is set into motion to repair the damage. This process is divided into predictable phases: blood clotting (hemostasis), inflammation, tissue growth (proliferation) and tissue remodeling (maturation). Blood clotting may be considered to be part of the inflammation stage instead of a separate stage.