ABSTRACT
The distinction between the normal aging of the cervical spine and pathological degeneration is blurred. In the normal aging cervical spine there are few changes until the age of 30. There is then progressive replacement of the glycosaminoglycan component of both nucleus pulposus and annulus fibrosus by collagen (fibrosis). The capacity of the nucleus to imbibe water drops by about 20% and the annulus becomes weakened by the decrease in structural protein. The vertebral end plates become sclerotic and vascular channels between the vertebral body and disc diminish in number. The result is a less elastic nucleus and an annulus which is more easily damaged. As the disc space narrows anteriorly due to circumferential bulging of the disc, the facet joints degenerate and become osteoarthritic. Each motion segment becomes more slack and traction osteophytes are seen at the margins of the vertebral bodies. The ligamentum flavum becomes hypertrophied and buckles inwards. Within the spinal canal, the neural structures may be compressed by osteophyte and bulging annulus (‘hard’ disc) or protruded nuclear material (‘soft disc’), resulting in neck pain, radiculopathy or myelopathy. These changes are commonest at C5/6, followed by C6/7 and C4/5.
