Sciatica refers to pain, weakness, numbness, or tingling in the leg. It is caused by injury to or pressure on the sciatic nerve. Sciatica is a symptom of another medical problem, not a medical condition on its own.

Causes, incidence, and risk factors

Sciatica occurs when there is pressure or damage to the sciatic nerve. This nerve starts in the lower spine and runs down the back of each leg. This nerve controls the muscles of the back of the knee and lower leg and provides sensation to the back of the thigh, part of the lower leg, and the sole of the foot.

Common causes of sciatica include:

• Slipped disk
• Piriformis syndrome (a pain disorder involving the narrow muscle in the buttocks)
• Pelvic injury or fracture
• Tumors

Symptoms

Sciatica pain can vary widely. It may feel like a mild tingling, dull ache, or a burning sensation. In some cases, the pain is severe enough to make a person unable to move.

The pain most often occurs on one side. Some people have sharp pain in one part of the leg or hip and numbness in other parts. The pain or numbness may also be felt on the back of the calf or on the sole of the foot. The affected leg may feel weak.

The pain often starts slowly. Sciatica pain may get worse:

• After standing or sitting
• At night
• When sneezing, coughing, or laughing
• When bending backwards or walking more than a few yards, especially if caused by spinal stenosis