Caused by compression or irritation of the sciatic nerves, sciatica is characterized by pain, numbness, and weakness in the lower back, buttocks, legs, and/or feet. It is important to note that while sciatica is commonly cited as a cause of lower back and leg pain, it actually is a set of symptoms rather than a true diagnosis. Sciatica varies greatly from case to case. It can occur when any one—or multiple—of the five spinal nerve roots of either the right or left (or both) is compressed or irritated. In most cases, however, the pain is only present on one side. Common causes of this type of pain include herniated or protruding discs in the lower back. Sciatica can usually be diagnosed with a physical examination and history of symptoms, with radiating or shooting pain in one leg being a telltale sign of the condition. If sciatica is suspected, it may be confirmed with one of several tests, the most common involving a straight leg-lift test. Patients may undergo diagnostic imaging tests such as MRI or computerized tomography to diagnose underlying conditions such as lumbar disc herniation. Treatment of sciatica varies depending on the underlying cause and may involve rest, physical therapy, spinal manipulation, administration of certain medications, or surgery.