Which stage involves a fragment of nucleus that has separated from the main disc mass?

• A. Prolapse
• B. Sequestration
• C. Extrusion
• D. Degeneration

Answer: (B)

In disc pathology, when a piece of nucleus pulposus breaks away and becomes completely separated from the main disc mass, this is sequestration. The key idea is that the fragment is free within the spinal canal and no longer connected to the rest of the disc, which distinguishes it from other stages. Prolapse/protrusion involves bulging disc material that remains part of the disc. Extrusion means the nucleus has pushed through the annulus and remains attached by a neck to the main disc. Degeneration is the general aging/degenerative process of the disc, not specifically about a detached fragment.