The sciatic nerve begins in the lower back, extends through the buttocks and goes down the length of the leg. It is the longest nerve in the body. The pain that occurs when this nerve becomes inflamed or compressed is called sciatica.

The pain can be felt at any part of the nerve or along its entire length. Sciatica may take several forms, including:

• Numbness
• Dull or sharp pain
• Mild to extreme pain
• Burning sensation
• "Pins and needles" tingling
• Pain that lasts for weeks or occurs only now and then
• Weakness in the affected area
• Pain when sneezing or coughing

Activity may make the pain more intense. For some patients, sciatica is worse at night.

Slipped discs account for most cases of sciatica. Discs are rings with tough exteriors and soft insides. They are located between the bones of the spine and act as shock absorbers.

Discs can become weak because of pressure from twisting and bending movements, heavy lifting, bad posture, pregnancy, obesity or other conditions that place strain on them. A weakened disc may herniate (bulge out). If the bulge pushes up against the sciatic nerve or crushes it, sciatica occurs.

It is estimated that one in every 50 people will have a herniated disc at some point in their lives.

After doing a thorough physical examination, the doctor may put the patient through a number of flexibility and muscle-strength tests.

X-rays,computed tomography (CT) scans and magnetic resonance imaging (MRI) )"pictures" may also be used to pinpoint the affected area of the spine and to rule out more severe spinal problems.

In most cases, sciatica goes away on its own after a few days or weeks and the patient is able to go back to routine activities.

At first, bed rest may be necessary until inflammation in the nerve is reduced. To keep the patient comfortable, anti-inflammatory drugs or simple pain medications may be taken. Applying heat or cold to the affected area may also help.

As soon as possible, the patient should resume being active by going back to work, doing physical therapy, walking, and stretching. This is the best way to reduce inflammation in the sciatic nerve.

When pain is so severe that the person is disabled, the doctor may give an epidural -- a shot in the spine that acts quickly to bring relief.

Surgery is recommended only if sciatica becomes overwhelming and lasts for an extended period of months. The surgeon will remove part of the bulging disc so that it is no longer pressing against the nerve.

• Cedars-Sinai Institute for Spinal Disorders
• Department of Neurosurgery
• S. Mark Taper Foundation Imaging Center