- Discussion:
- nucleus pulposus consists of a network of delicate collagenous fibers in a mucoprotein gel rich in polysaccharide;
- contains
type II collagen;
- nucleus has a high water content, apparently the result of imbibition by the gel;
- it functions to resist compressive loads;
- water content declines with advancing age and is reduced by pressure borne by the disc, accounting
for loss in the height of a person during an active day;
- gradual loss of
proteoglycan content explains the loss of water w/ aging;
- after the third decade, there is gradual loss of fluid and concomitant fibrous replacement of the nucleus;
- by sixth or seventh decade the nucleus has become fibrocartilage;
- w/ age, the
anulus shows coarsened and hyalinized fibers and fissuring of the lamellae;
- Herniation:
- herniation of intervertebral disc occurs most often in lumbar or cervical regions where motion
and stress are greatest;
- this may involve a simple bulging of the disc or complete herniation of a portion of the nucleus
pulposus through the anulus fibrosus;
