Intervertebralring

Intervertebralring is a term used to describe the fibrous ring surrounding the nucleus pulposus in an intervertebral disc. In most anatomical references this structure is known as the annulus fibrosus, but some literature uses Intervertebralring as an alternative name. The ring consists of concentric lamellae that enclose the gelatinous core and help maintain disc integrity under load.

Anatomically, the annulus fibrosus is organized into multiple layers of collagen-rich fibers. The outer lamellae display oblique fiber orientations that alternate with each successive layer, which enhances resistance to torsional and tensile stresses. The inner lamellae transition toward a higher content of hydrated, cartilaginous matrix. The outer portion of the ring is more densely innervated and vascularized than the inner part; overall, the annulus fibrosus is largely avascular in adulthood, with nutrition supplied by diffusion through the adjacent endplates.

Functionally, the intervertebralring serves to contain the nucleus pulposus, distribute axial loads, and resist complex mechanical forces such as bending, twisting, and compression. Its integrity is essential for disc stability and coordinated motion between vertebral bodies.

Developmentally, the ring derives from the sclerotome portion of somites during embryogenesis, integrating with the vertebral endplates and nucleus to form a functional unit.

Clinical relevance centers on annular tears or fissures within the ring, which can contribute to disc degeneration and herniation. Degenerative changes may alter mechanical properties and imaging features, with MRI sometimes showing annular fissures or related signal changes.