Sciatica

Article By:

Hall, Hamilton Department of Surgery, University of Toronto, Toronto, Canada.

Last reviewed:July 2020

DOI:https://doi.org/10.1036/1097-8542.607000

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• Sciatica, published June 2014:Download PDF Get Adobe Acrobat Reader

A specific pattern of leg pain that follows the course of the sciatic nerves. The sciatic nerves refer to a pair of long nerves that originate in the lower spinal cord and send fibers to the upper thigh muscles and the joints, skin, and muscles of the legs (see illustration). Sciatica is usually caused by injury to one or more of the sciatic root nerves within the lower spinal canal. The contributing nerves, that is, the last two lumbar nerves and first two sacral nerves, exit sequentially through openings on each side of the spine. The individual nerves then enter common protective sheaths to become the sciatic nerves. Each one leaves the pelvis and runs down the back of the leg to the foot. Along the way, branches supply the skin, particularly in the lower leg, and some of the muscles that move the hip and bend the knee. The sciatic nerves control all the muscles that enable walking on the heels and toes. See also: Nerve; Nervous system (vertebrate); Pain; Spinal cord; Spinal cord disorders; Vertebra

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