Radiographic evidence of cervical spondylosis increases in each decade: 5% to 10% ages 20 to 30; >50% by age 45; >90% after age 60, but symptomatic myelopathy rare.

Narrow spinal canal from: loss of water from intervertebral disc; degenerative changes in disc; protrusion of annulus fibrosus and osteophytes (spondylotic bars) into spinal canal.

Rare syndrome: ossification of posterior longitudinal ligament.