In addition to the structural arthritic changes causing narrowing of the spinal canal, DLSS has an important dynamic component. The volume of the spinal canal and degree of epidural pressure and ischemia of the spinal nerves can change depending on spinal posture. Both lumbar flexion (stooping forward), and sitting increase the diameter of the canal and reduce spinal nerve ischemia, and correspond with a reduction or elimination of lower extremity symptoms. Conversely, lumbar extension or increasing the lumbar lordosis (which occurs when standing) reduces the diameter of the spinal canal and increases spinal nerve ischemia, and corresponds with increased lower extremity symptoms. The ability to reduce symptoms of DLSS by changing spinal posture/structural alignment and/or increasing blood flow to the spinal nerve provides potential mechanisms for developing interventions to improve symptoms and walking ability.