Science today isn't the same as the science 2000 years ago was but some principles remain the same. The human knowledge constantly grows but with more knowledge there comes even more mysteries and unsolved questions, so science is always going forward.
Causes. The most common cause of a cervical herniated nucleus pulposus is gradual degeneration of the disc, attenuation (weakening) of the posterior annulus fibrosis, and subsequent protrusion of the nucleus pulposus into the spinal canal causing compression of the nerve root.
When a disc is herniated, a problem in the annulus can cause the jelly-like nucleus to push out into the spinal canal. This can lead to pressure on a spinal nerve, in which case the patient may experience pain, numbness or weakness in the back, legs or arms.