The sciatic nerve (the longest nerve in your body) runs from your pelvis through your hip area and buttocks and down each leg. It divides into the tibial and peroneal nerves at the level of your knees. The sciatic nerve controls many of the muscles in your lower legs and provides feeling to your thighs, legs and feet.

The term sciatica refers to pain that radiates along the path of this nerve — from your back into your buttock and leg. The discomfort can range from mild to incapacitating, and may be accompanied by tingling, numbness or muscle weakness. Rather than a disorder in and of itself sciatica is a symptom of another problem, such as a herniated disk, that puts pressure on the nerve.