Causes of sciatic nerve pain in the legs include lumbar spinal stenosis, degenerative disc disease, spondylolisthesis and pregnancy, according to WebMD. Other causes of pain from the sciatic nerve include being overweight, wearing high heels and sleeping on a mattress that is too hard or soft.
The symptoms of sciatica occur due to the irritation of the root or roots of the lumbosacral spine or lower lumbar, claims WebMD. The narrowing of the spinal canal in the lower back may contribute to this pain, and degenerative disc disease, which results from the break down of the discs in the vertebrae, may also cause sciatica. It is also possible that one vertebra can slip over another one in a condition known as spondylolisthesis, which is another possible cause of sciatica.
In most cases, sciatica only affects one side of the lower body, such as the right leg, explains WebMD. The pain may extend from the lower back to the thigh or even through the entire leg. Depending on where the nerve irritation occurs, it is also possible that the pain can extend through the toes and foot. Some people find sciatica to be debilitating, but for others, it may only be an irritant. Individuals should seek emergency medical assistance if they experience weakness or numbness in the upper thighs or a loss of bowel or bladder control with sciatica.