Sciatica is caused by irritation of the sciatic nerve. Usually, there is no specific injury that is related to the onset of sciatica. Occasionally, the pain will suddenly begin after lifting something heavy or moving quickly. The following are causes of sciatica:
- A herniated disc (sometimes called a slipped disc): This is the most common cause of sciatica.
- Discs are the cushions between the bones in the back. They act like "shock absorbers" when we move, bend, and lift. They are the size and shape of checkers.
- There is a tough ring around the outside and a thick jellylike center inside (called a nucleus pulposus). If the outer edge of the disc ruptures, the center can push through and put pressure on the sciatic nerve, leading to the pain of sciatica (referred to as a herniated nucleus pulposus as the syndrome).
- Spinal stenosis, a narrowing of the canal that contains the spinal cord: As we age, the bone can overgrow and put pressure on the sciatic nerve. Many people with spinal stenosis have sciatica on both sides of the back.
- Spondylolisthesis, a condition in which one backbone has slipped forward or backward over another backbone, results in pressure on the sciatic nerve.
- A pinched or stretched sciatic nerve
- Piriformis syndrome causes the sciatic nerve to become trapped deep in the buttock by the piriformis muscle. The symptoms are the same as those of sciatica.
- Sciatica can also be caused by other effects of aging, such as osteoarthritis and fractures due to osteoporosis.
- Many women experience sciatica during pregnancy.
- Rarely, sciatica is a symptom of a far more serious problem, such as tumor, blood clot, or abscess (boil).
Picture of a herniated lumbar disc
Medically Reviewed by a Doctor on 3/24/2015
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