What occurs in a disc extrusion?

A disc extrusion refers to a specific condition where the inner gel-like substance of the intervertebral disc, known as the nucleus pulposus, breaks through the outer layer, called the annulus fibrosus. In this scenario, the nucleus pulposus protrudes into the neural canal, which can potentially compress nearby spinal nerves and lead to pain or neurological symptoms.

This process is distinct from other conditions such as dehydration of the disc or changes in its structure. While hydration loss does occur over time with age, it is not the primary characteristic of an extrusion. Compression of the disc itself can happen, but it does not define the extrusion process. Similarly, hardening of the outer layer does not accurately describe an extrusion, as the primary issue involves the position of the inner material rather than changes to the outer layer's texture or solidity.