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.
There is a tough ring around the outside and a thick jellylike center inside (called a nucleus pulposus). If the outer edge of the disc ruptures, the center can push through and put pressure on the sciatic nerve, leading to the pain of sciatica (referred to as a herniated nucleus pulposus).