Sciatica is irritation of the sciatic nerve, a major nerve that passes down the back of each thigh. The sciatic nerve originates in the lower spine and travels deep in the pelvis to the lower buttocks. From there it passes along the back of each upper leg and divides at the knee into branches that go to the feet. Sciatica typically causes pain that shoots down the back of one thigh or buttock.

Anything that causes irritation or puts pressure on the sciatic nerve can cause sciatica. The most common cause is probably a sprain or strain of muscles or ligaments in the area, and for this reason sciatica is often associated with low back pain. The cushions between the bones of the spine—the discs—can also cause sciatica when they bulge out of place or degenerate. Other causes of sciatica include spinal stenosis (narrowing of the spinal canal in the lumbar area), spondylolisthesis (slippage of a bone in the low back) and, very rarely, benign or malignant tumors.

Diagnosis of sciatica is made by symptoms, neurologic evaluation, and tests, such as nerve conduction study, x -ray, and MRI scan. Common symptoms include the following:

• Burning, tingling, or a shooting pain down the back of one leg
• Pain in one leg or buttock that is worse with sitting, standing up, coughing, sneezing, or straining
• Weakness or numbness in one leg or foot

More serious symptoms that sometimes occur in sciatica include difficulty walking, standing, or moving; increasing weakness or numbness in the leg or foot; and loss of bowel or bladder control.

In most cases, sciatic pain resolves on its own without specific treatment. Bedrest, although still sometimes recommended, is probably not helpful.^1,2 However, physical therapy techniques and steroid injections have shown promise. If permanent nerve damage is threatened, surgery may be necessary.

Attacks of sciatica tend to recur. Certain common sense steps that may help prevent recurrences include the following:

• When lifting, hold the object close to your chest, maintain a straight back, and use your leg muscles to slowly rise.
• Practice good posture to reduce pressure on your spine.
• If possible, avoid sitting or standing in one position for prolonged periods.
• Use a low back support during prolonged sitting. Rest one foot on a low stool if standing for long periods.
• Sleep on a firm mattress.
• Exercise regularly, at least 30 minutes most days of the week. Good choices include walking, swimming, or exercises recommended by your doctor or physical therapist.
• Consider job retraining if your work requires a lot of heavy lifting or sitting.