The sciatic nerve is the largest nerve in the human body and one of the most common causes of leg pain. The term sciatica is used to describe the symptoms of pain occurring in the leg and lower back. Some use the term specifically to mean a nerve dysfunction caused by compression of one or more lumbar or sacral nerve roots from a spinal disc herniation.
When the liquid center of a disc bulges outwards, herniation occurs. The bulged disc can then tear against external ring fibers, contact the spinal canal, and compress a nerve root against the lamina or pedicle of a vertebra. This causes sciatica. The liquid extruded when this happens can cause inflammation and swelling of the surrounding tissue which can further compress the nerve root into the confined space of the spinal canal.
Sciatic pain typically runs through the lower back and down the sciatic nerve through the leg and can even run all the way down to the foot. Numbness, tingling, burning, and pricking sensations are all symptoms that may occur in cases of sciatic injury.
Sciatica is caused by compression of lumbar nerves, sacral nerves, and/or the sciatic nerve. Sciatic damage can be permanent, thus it is important that you seek medical attention if you are suffering from these symptoms.