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.
Herniated Nucleus Pulposus. There are soft-tissue discs between the bony vertebral bodies in your thoracic spine (rib cage area) that are called intervertebral discs. These discs are composed of a soft gel-like center called the nucleus pulposus, and a tough outer layer that surrounds the disc called the annulus fibrosis. The intervertebral disc creates a joint between each of the vertebral bodies that allows them to flex and extend, rotate slightly, and laterally bend.