Spinal stenosis results from new bone and soft tissue growth on the vertebrae, which reduces the space in the spinal canal.  When the nerve roots are pinched, a painful burning, tingling and/or numbing sensation is felt from the lower back down to the legs and sometimes all the way to the feet.

In a healthy spine, the spinal canal has a rounded triangular shape that holds the spinal cord without pinching.  Nerve roots leave the spinal canal through openings called nerve root canals, which are also free of obstruction.