Sciatica is pain, tingling, or numbness produced by an irritation of the nerve roots that lead to the sciatic nerve. The sciatic nerve is formed by the nerve roots coming out of the spinal cord into the lower back. It goes down through the buttock, then its branches extend down the back of the leg to the ankle and foot.
The most common cause of sciatica is a bulging or ruptured disc in the spine pressing against the nerve roots that lead to the sciatic nerve. But sciatica also can be a symptom of other conditions that affect the spine, such as narrowing of the spinal canal, bone spurs (small, bony growths that form along joints) caused by arthritis, or nerve root compression caused by injury. In rare cases, sciatica can also be caused by conditions that do not involve the spine, such as tumors or pregnancy.
Symptoms of sciatica include pain that begins in your back or buttock and moves down your leg and may move into your foot. Weakness, tingling, or numbness in the leg may also occur.
Sciatica is diagnosed with a medical history and physical exam. Sometimes X-rays and other tests such as magnetic resonance imaging (MRI) are done to help find the cause of the sciatica.