Sciatica is a symptom. It consists of leg pain, which might feel like a bad leg cramp, or it can be excruciating, shooting pain that makes standing or sitting nearly impossible.

The pain might be worse when you sit, sneeze, or cough. Sciatica can occur suddenly or it can develop gradually. You might also feel weakness, numbness, or a burning or tingling ("pins and needles") sensation down your leg, possibly even in your toes. Less common symptoms might include the inability to bend your knee or move your foot and toes.

What causes sciatica?

Sciatica might be a symptom of a "pinched nerve" affecting one or more of the lower spinal nerves. The nerve might be pinched inside or outside of the spinal canal as it passes into the leg.

Conditions that cause sciatica:

  • A herniated or slipped disc that causes pressure on a nerve root — This is the most common cause of sciatica.
  • Piriformis syndrome — This develops when the piriformis muscle, a small muscle that lies deep in the buttocks, becomes tight or spasms, which can put pressure on and irritate the sciatic nerve.
  • Spinal stenosis — This condition results from narrowing of the spinal canal with pressure on the nerves.
  • Spondylolisthesis — This is a slippage of one vertebra so that it is out of line with the one above it, narrowing the opening through which the nerve exits