Over time, the fluid in the cushioning disc between the vertebra
decrease, which affects the ability of the disc to function normally.
Fissures can develop in the annulus, or outer layer of the disc,
making it more susceptible to tears. Vertebral endplate thinning can
occur, which affects the blood supply to the disc. These factors can
also lead the facet joints on the side of the vertebra to experience
an increased workload, which can contribute to degeneration as well.
As degeneration occurs, minor trauma or unusual activity can produce
back pain. This can produce muscle pain and spasms, tears in the outer
ring of the disc, or annulus, and further degeneration of the nucleus
or inner cushioned part of the disc. This can progress to laxity, and
instability, as well as entrapment on nerve roots as they exit the vertebra.
Additionally, bone spurs or osteophytes develop in and around the
facet joint and discs. The ligaments can thicken and cause narrowing
of the spinal canal and compression on the spinal cord. This can cause
central spinal stenosis or nerve root entrapment. Movement, or
spondylolithesis, may occur, which can cause instability and movement
in the spinal column. This may produce pain or weakness, particularly
in an arm or leg.
Bones can also lose their density and develop osteopenia or
osteoporosis. They can be more likely to fracture or break with
trauma. Lifestyle habits such as smoking, being overweight, lack of
exercise or exercising too much can also affect bone quality, making
your spine more at risk of injury.