This document summarizes the pathophysiology and classification of burns. It describes how burns are caused by thermal, radiation or chemical injury, leading to tissue destruction. Burn depth is classified as superficial, deep partial thickness, or full thickness depending on the extent of epidermal and dermal damage. Burn extent is estimated using methods like the Rule of Nines or Lund-Browder chart based on percentage of total body surface area affected. Classification determines burn management and predicts healing outcomes.