What is a disc extrusion?

What is a disc extrusion?

• A. Herniation through all annulus fibrosus layers while remaining attached to the disc
• B. Herniation through all annulus fibrosus layers while detached from the disc
• C. A free disc fragment with no attachment
• D. Herniation that penetrates the PLL

Answer: (A)

The situation described by extrusion is when disc material has broken through the full thickness of the annulus fibrosus and extends beyond the disc edge, but remains connected to the parent disc by a narrow stalk. This continuity with the disc is what sets extrusion apart from other forms: a protrusion bulges still within the annulus and a broad base, while sequestration is a free fragment completely detached from the disc. The fact that the material may or may not penetrate the posterior longitudinal ligament can occur with extrusions, but the defining feature is that the extruded portion stays attached to the original disc.

The situation described by extrusion is when disc material has broken through the full thickness of the annulus fibrosus and extends beyond the disc edge, but remains connected to the parent disc by a narrow stalk. This continuity with the disc is what sets extrusion apart from other forms: a protrusion bulges still within the annulus and a broad base, while sequestration is a free fragment completely detached from the disc. The fact that the material may or may not penetrate the posterior longitudinal ligament can occur with extrusions, but the defining feature is that the extruded portion stays attached to the original disc.