Sciatica is a term used to describe a set of symptoms rather than a specific medical condition. It refers to pain that radiates along the path of the sciatic nerve, which is the longest nerve in the human body. The sciatic nerve starts in the lower back (lumbar spine) and runs down the back of each leg. Sciatica is often caused by compression or irritation of the sciatic nerve or its nerve roots. It typically affects one side of the body and can range from mild to severe. Dr. Barnard is skilled at figuring out the root cause of your sciatica and offering long lasting, natural sciatica leg pain treatment.