Sciatica is nerve pain down the back of one or both legs caused by pressure on the sciatic nerve in the back. The pressure is usually caused by a prolapsed (‘slipped’) disc in the back. However, it can also be produced by pressure on the nerve as it passes through the buttocks and can be caused by sitting with keys, coins, etc. in your back pocket, or on a hard surface. The spine is made up of a vertical column of bones called vertebrae that are separated by a disc consisting of a soft gelatinous centre surrounded by a tough outer ring of fibrous tissue. These discs act as a shock absorber between the vertebrae, protecting the bone from impact that would otherwise occur during any physical movement.
The sciatic nerve is a large nerve, formed from nerve roots that originate from the spinal cord. These nerve roots pass out between the disc spaces and join up to form the sciatic nerve. It passes from the spine into the buttock, then into the back of the thigh and leg. The sciatic nerve controls sensation and the nerve impulses for power to part of the legs and feet. In sciatica, prolapsed or ‘slipped’ discs tend to bulge and press on the intervertebral nerve(s). This pressure irritates the nerve, causing referred pain.
- Hot pain in the buttock
- Aching in the buttock, back of the thigh (hamstring) and calf
- Pain in the ankle and foot
- Pins and needles relating to one or more branch of the sciatic nerve
- Loss of feeling in the leg and/or foot
- Increased pain when lifting, straining or coughing
- Loss of power to the muscles of the leg and foot
Most cases of sciatica resolve, on their own, within two to three months. Sciatica can also be caused by osteoarthritis where a narrowing of the nerve tunnel between can result. Therefore, anyone who suffers from disk degeneration, as a consequence of ageing, tend to be troubled the most by sciatica.
Recent studies suggest that there is no long-term benefit in the treatment of sciatica through bed rest and lying on a firm/hard surface, as it does not speed recovery when compared with the sufferer remaining as active (within reason) as they can. In fact there is evidence that too much rest may delay the recovery.