spinal nerve n.
Any of 31 pairs of nerves emerging from the spinal cord, each attached to the cord by two roots, anterior or ventral and posterior or dorsal, the latter provided with a spinal ganglion. The two roots unite in the intervertebral foramen but divide again into ventral and dorsal rami, or anterior and posterior primary divisions, the former supplying the foreparts of the body and limbs, the latter the muscles and skin of the back.
in vertebrates, any one of many paired peripheral nerves that arise from the spinal cord. In humans there are 31 pairs: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. Each pair connects the spinal cord with a specific region of the body. Near the spinal cord each spinal nerve branches into two roots. One, composed of sensory fibres, enters the spinal cord via the dorsal root; its cell bodies lie in a spinal ganglion that is outside the spinal cord. The other, composed of motor fibres, leaves the spinal cord via the ventral root; its cell bodies lie in specific areas of the spinal cord itself.
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