Causes of Sciatica and Piriformis Syndrome
In about 90% of cases, sciatica is caused by a herniated disc compressing the root of the sciatic nerve.2 Other causes include degenerative disc disease, spinal stenosis, spondylolisthesis, pregnancy, tumors, or infection.
Sciatica typically begins as a functional issue. The structural issues that occur in the lumbar spine to cause sciatica are most often a result of the way we function: the way we habitually sit, stand, and move. Repetitive compression of the lumbar spine or constant compression from tight lower back muscles cause discs to thin and herniate, vertebrae to move out of alignment, the spinal canal to narrow, and bone spurs to develop.