Discs are flexible spacers between the bony vertebrae that act as “shock absorbers” for the spine and allow motion of the spinal column. They consist of a fibrous outer rim called the annulus and a softer inner portion called the nucleus. The annulus provides stability while allowing flexibility for twisting and bending. The nucleus supplies cushioning that supports the upper body weight. DDD causes the nucleus to dehydrate and shrink, drawing the vertebrae closer together. The resulting loss of disc height can cause narrowing of the spinal nerve openings, which may result in back and/or leg pain.
