spinal nerve
any of the 31 pairs of nerves that originate in the gray matter of the spinal cord and emerge through openings between the vertebrae of the spine to extend into the body’s dermatomes (skin areas) and skeletal muscles. The spinal nerves comprise 8 cervical nerves, 12 thoracic nerves, 5 lumbar nerves, 5 sacral nerves, and 1 coccygeal nerve. Each attaches to the spinal cord via two short branches, a dorsal root and a ventral root. See also spinal root.