Sciatica is a health condition characterised by pain going down the leg from the lower back.  This pain may go down the back, outside, or front of the leg.   Onset is often sudden following activities like heavy lifting, though gradual onset may also occur.   The pain is often described as shooting.  Typically, symptoms are only on one side of the body.  Certain causes, however, may result in pain on both sides.  Lower back pain is sometimes present.  Weakness or numbness may occur in various parts of the affected leg and foot.

About 90% of sciatica is due to a spinal disc herniation pressing on one of the lumbar or sacral nerve roots.  Spondylolisthesis, spinal stenosis, piriformis syndrome, pelvic tumours, and pregnancy are other possible causes of sciatica.