When the open spaces in the spine narrow and put pressure on the spinal cord as well as the nerves that are traveling along the spine, spinal stenosis occurs. This most often occurs in the lower back and the neck. Some people with spinal stenosis will have no symptoms at all but others can have muscle weakness, pain, numbness, and even problems with the function of their bowel or bladder. It is caused most often by changes in the spine from wear and tear associated with aging.
Spinal Stenosis Joseph Smith, PhD