Final answer:
Fourth-degree burns are coded separately from the other types of burns. First-degree burns affect only the epidermis, second-degree burns go deeper and result in blistering, and third-degree burns fully extend into the epidermis and dermis. Fourth-degree burns are the most severe, affecting the underlying muscle and bone.
Step-by-step explanation:
When burns occur in varying degrees, fourth-degree burns are coded separately from the others. First-degree burns affect only the epidermis and heal on their own within a few days. Second-degree burns go deeper and result in blistering of the skin. Third-degree burns fully extend into the epidermis and dermis, requiring medical attention. Fourth-degree burns are the most severe, affecting the underlying muscle and bone.