A dermatome is a specific area of skin that is mainly supplied by a single spinal nerve root. Each dermatome corresponds to a particular segment of the spinal cord, allowing healthcare professionals to assess nerve function and diagnose conditions related to nerve damage or injury. Understanding dermatomes is crucial in fields like neurology and physiotherapy, as they help identify the location of pain or sensory loss. For example, if a patient experiences numbness in a specific area, doctors can determine which spinal nerve may be affected based on the corresponding dermatome.