Sciatica is a symptom of a medical problem that causes pressure on the sciatic nerve that runs from the spine down the back of each leg. Its purpose is to move the back of the knee and lower leg, as well as to provide sensation to those areas and the sole of the foot, according to the National Institutes of Health. Injuries, growths or structural problems can press on the sciatic nerve, causing pain, burning, tingling, weakness or numbness in the buttock and leg on one side. Treatment focuses on pain relief and correction of the underlying problem.
Herniated Disk
The most common cause of sciatica is pressure on the root of the nerve by a protruding disk. The disks are gel-filled pads that cushion the spaces between the vertebrae in the spine, according to the American Association of Orthopaedic Surgeons. The wear-and-tear of aging or sudden pressure on the spine can damage the outer covering of a disk, allowing the gel to leak out and irritate the nerve ending. Herniated disks occur most often between the ages of 30 and 50, and are usually treated with rest, stretching and pain relievers. If the pain is severe and persistent, surgery may be needed to relieve the pressure on the sciatic nerve.
Bony Abnormalities
The spine is a series of bones or vertebrae that protect the nerves of the spinal cord. When the bones shift or narrow, however, they can cause pressure on the nerves. Spinal stenosis or narrowing of an area of the spine can cause sciatica if the narrowing occurs in the lower back, according to the Mayo Clinic. When a vertebra slips forward, a condition called spondylolisthesis, the bone may pinch the nerve and cause pain.
Trauma
Trauma to the spine can cause sciatic nerve pain, according to the Mayo Clinic. A fall, blow to the spine, car accident or other injury can injure the nerve, causing numbness, pain or tingling. Injuries can also cause piriformis syndrome--tightening or spasms in the piriformis muscle that runs between the spine and the femur or thighbone--that compresses the sciatic nerve. Pelvic injuries can also cause sciatic, adds the National Institutes of Health.
Growths
Rarely, tumors in the sciatic nerve, spinal cord or in the space between the spinal cord and the vertebrae can press on the nerve roots or the spinal cord, causing sciatic nerve pain, notes the Merck Manual. Abscesses may also produce sciatic symptoms. Treatment of the underlying cause relieves the symptoms.
