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.
A bulging or herniated disk occurs when the outer covering of the cartilage between the spinal vertebrae tears. Consequently, the jelly-like nucleus inside the disk gets pushed to the weaker side and causes the disk to bulge and put pressure on spinal nerves.