Somatic Nervous System

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somatic nervous system

[sō′mad·ik ′nər·vəs ‚sis·təm]
The portion of the nervous system concerned with the control of voluntary muscle and relating the organism with its environment.

Somatic Nervous System


the part of the nervous system that innervates the muscles of the body and makes sensory and motor functions possible. In vertebrates, somatic muscles include the striated muscles of the skeleton, which are innervated by the motoneurons of the anterior horns of the spinal cord and by some motor nuclei of the brainstem. These motoneurons are coordinated by direct or indirect (through interneurons) synaptic influences that come from other motoneurons, from sensory neurons that obtain information from muscles and tendons, and from the higher motor centers situated in various parts of the brain. The division of the nervous system into the somatic and visceral systems, introduced by the British physiologist W. H. Gaskell, is very arbitrary. Both terms are only of historical interest, and their use in scientific literature is decreasing.