The intervertebral discs are the elastic ring-shaped structures connecting the bodies of the vertebrae. It constitutes 20–33% of the entire height of the vertebral column1, a number that decrease with age and inevitable progressive disc degeneration2.
The cervical intervertebral discs differ significantly from the lumbar discs1 – the cervical anulus fibrosus does not consist of concentric lamellae of collagen fibers that uniformly surround the nucleus pulposus. Rather, the cervical anulus is crescentic, being thick anteriorly but tapering in thickness laterally as it approaches the uncovertebral region.2.
The superficial fibers of the anulus fibrosus run more vertically compared to the lumbar discs. Deeper the anulus fibrosus transforms into the homogeneous mass – the fibrocartilage core2 –, that, possibly, during disc aging and maturation, gradually substitutes the nucleus pulposus3–5.