What is the name of the firm outer layer of the intervertebral disc?

The firm outer layer of the intervertebral disc is known as the annulus fibrosis. This structure is crucial because it provides strength and stability to the disc, allowing it to withstand the various stresses and pressures that occur during movement and weight-bearing activities. The annulus fibrosis is composed of multiple layers of collagen fibers arranged in a specific orientation, which contributes to its ability to absorb and distribute loads while also protecting the inner gel-like core, the nucleus pulposus. The annulus plays a key role in the overall integrity and functionality of the intervertebral disc, making it critical for spinal health and mobility.