(See also: Annular Tear)
Discussion
- anulus fibrosus makes up peripheral portion of disk structure;
- composed of fibrocartilage and type I collagen;
- fibers of anulus run obliquely between vertebrae and are arranged primarily in concentric layers;
- direction of the fibers in successive layers alternates, w/ one layer crossing another at angles of 30-60 deg;
- at periphery some annular fibers extend past cartilage edge plate to enter the bone of body as Sharpey's fibers;
- deep fibers either insert into the cartilage at each end of disc or bend w/ nucleus pulposus;
Innervation
- neural fibers are found in the outer rings of anulus;
- nerve fibers are branches of the sinu vertebral nerve dorsally;
- ventral branches arise from the sympathetic chain that courses anterolaterally over the vertebral bodies;
Annular Tear »
Disc Herniation »
- anulus is wider anteriorly than posteriorly (i.e., Nucleus pulposus is situated eccentrically)