The intervertebral disc and the adjacent vertebrae undergo changes with increasing age. As a result of associated degeneration, the disc loses its ability to retain water. These changes are usually present without causing apparent pain but as the annulus fibrosis thins and radial slits appear in it, this allows the nucleus (annulus pulposus) to bulge and even to rupture through it, resulting in “slipped disc”.

While this degeneration occurs with age, severe trauma may also cause a disc to herniate (bulge out). Some common causes include:

• A sudden fall or accident.
• Heavy weight lifting.
• Long term strain over the back.