Definition

Sciatica is a term given to any painful condition of the leg that originates in the lower back and descends down the leg. Because it tends to involve a single nerve tract it is designated as mononeuropathy (localized nerve disorder).

The cause of this pain is the neuropathy defined by the inflammation and swelling of the large sciatic nerve that originates from the exit of an intervertebral nerve plexus between one of the large lumbar vertebral discs. A portion of the sciatic nerve also originates from the sacrum. The name for the region from which this nerve emanates is the sacral plexus. It encompasses the lumbar vertebra L 4–5 through the sacral vertebra S 1–3. The intervertebral nerves join to form one of the larger nerve tracts in the body, the sciatic nerve. This nerve tract winds over the pelvic bones and down the proximal...