This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'Area of skin supplied by single nerve supply \nSelect and explain. \nA. Dermatome, B. Pedicle, C. Graft, D. Dermoid', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A dermatome is an area of skin that is mainly supplied by a single spinal nerve. There are eight cervical nerves (C1 being an exception with no dermatome), twelve thoracic nerves, five lumbar nerves and five sacral nerves. Each of these nerves relays sensation (including pain) from a particular region of skin to the brain. Spinal nerves not only play an important role in differentiation and motor innervation of the limb musculature, but also provide sensory innervations for the dermatomes.', 'role': 'assistant'}]