What type of herniated disk occurs when the nucleus moves completely through the annulus?

The type of herniated disk that occurs when the nucleus of the intervertebral disk moves completely through the annulus is known as a prolapsed disk. In this condition, the inner gel-like core, or nucleus pulposus, has ruptured through the outer fibrous layer, or annulus fibrosus, allowing the nucleus to protrude beyond the usual confines of the disk. This can create pressure on nearby spinal nerves, leading to pain and other neurological symptoms.

Understanding the term "prolapsed" is crucial, as it specifically indicates that the nucleus has breached the annular wall entirely. This is different from other terms like 'sequestrated,' which involves the nucleus being separated from the rest of the disk material but not necessarily exiting through the annulus. An 'extruded' disk refers to material that has herniated through the annulus but may not have moved completely through; it can still be attached to the disk. A 'disc bulge' describes a condition where the disk extends outward, but without a rupture of the annulus.

By recognizing the distinctions in these terms, it becomes clearer how a prolapsed disk represents a complete displacement of the nucleus through the annulus, leading to its classification in this