Sciatica is the common name for pain that radiates down the back of the leg, however, the site of pain is not the site of injury.
Swelling of local ligaments or joints, muscle spasm or direct pressure from a disc bulge or herniation causes irritation and inflammation of the Sciatic nerve. This in turn causes pain and, depending on the amount of pressure on the nerve, can also cause pins and needles or numbness.
The Sciatic nerve is made up of the last 3 nerves exiting the lumbar spine. These nerves merge, run through the buttock muscles, into the low leg providing the nerve supply for that area. Due to its long course, pressure can come from one of several areas. Joint or muscle inflammation in the low back can cause irritation. A disc herniation causes constant pressure and severe pain in the nerve. Also, as the sciatic nerve passes through the buttock, it is possible for a muscle spasm in that area to cause pain.
It is essential to do a thorough examination of the low back, pelvis and leg as well as relevant tests to isolate the site of the nerve irritation. Only then can an effective treatment program be planned.