Sciatica is a term used broadly by most patients to describe pain referring down the back or side of a leg. Any of the nociceptive (pain-producing) structures of the lumbar spine may cause low back pain, or pain referring down the leg. The sciatic nerve is made up of a collection of nerves which merge together after exiting the spine and travel down the back of the leg and into the calf.
True sciatica is due to an irritation of this nerve either mechanically (e.g. disc bulge / derangement) or chemically (inflammatory changes) and is often experienced as a sudden onset of shooting pains into the back of the leg or calf. Leg pain can also be coming on gradually over a number of hours or days and extend into the foot. Successful elimination of the pain is dependent on identifying the cause of the nerve irritation through careful clinical assessment, x-ray imaging or magnetic resonance imaging (MRI).