usually associated with some type of activity that causes undue stress (often hyperflexion) on the tissues of the lower back. Often symptoms do not appear at the time of injury but develop later because of a gradual increase in pressure on the nerve irritation and muscle strain. One test is the straight-leg-raise. This test is positive for lumbar disk herniation when radicular pain occurs. MRI, CT scans are generally not done unless trauma or systemic disease (e.g., cancer, spinal infection) is suspected.