spinal root

physiology

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Last updated

July 14, 2026

Quick Summary

A spinal nerve is a paired peripheral nerve that originates from the spinal cord in vertebrates. There are 31 pairs in humans, categorized by region: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. Each pair connects the spinal cord to a specific body area.

Near the spinal cord, each nerve splits into two roots. The dorsal root contains sensory fibers, with cell bodies located in a spinal ganglion outside the spinal cord. The ventral root carries motor fibers, with cell bodies situated within the spinal cord itself. The proximal end of a nerve, especially the initial segment of a spinal nerve where it branches from the spinal cord, is referred to as a nerve root.

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nervous system disease
Spinal nerve roots
…signs of damage to the spinal roots are the same as for peripheral-nerve damage except that the area of involvement is restricted to the area supplied by the spinal roots rather than the nerves. Also, generalized symmetrical sensory loss is not seen in spinal root damage.
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…signs of damage to the spinal roots are the same as for peripheral-nerve damage except that the area of involvement is restricted to the area supplied by the spinal roots rather than the nerves. Also, generalized symmetrical sensory loss is not seen in spinal root damage.
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human nervous system
Accessory nerve (CN XI or 11)
…levels C₁–C₄ (known as the spinal root). The cranial root originates from the nucleus ambiguus and exits the medulla below the vagus nerve. Its fibers join the vagus and distribute to some muscles of the pharynx and larynx via pharyngeal and recurrent laryngeal branches of that nerve. For this reason,…
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…levels C₁–C₄ (known as the spinal root). The cranial root originates from the nucleus ambiguus and exits the medulla below the vagus nerve. Its fibers join the vagus and distribute to some muscles of the pharynx and larynx via pharyngeal and recurrent laryngeal branches of that nerve. For this reason,…
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