Spinal stenosis (or narrowing) is a common condition that occurs when the small spinal canal, which contains the nerve roots and spinal cord, becomes compressed. This causes a "pinching" of the spinal cord and/or nerve roots, which leads to pain, cramping, weakness or numbness. Depending on where the narrowing takes place, you may feel these symptoms in the lower back and legs, neck, shoulder or arms. Usually, the narrowing is caused by osteoarthritis, or "wear and tear" arthritis, of the spinal column and discs between the vertebrae (the bones of the back). It may also be caused by a thickening of the ligaments in the back, as well as by a bulging of the discs that separate the vertebrae. Symptoms of spinal stenosis often start slowly and get worse over time. Pain in the legs may become so severe that walking even short distances is unbearable. Frequently, sufferers must sit or lean forward over a grocery cart, counter-top or walker to temporarily ease pain.