What does the annulus fibrosus consist of?

The annulus fibrosus is a crucial component of the intervertebral disc, primarily made up of a dense layer of collagen fibers and some elastin fibers. This structure surrounds the nucleus pulposus, which is the gel-like center of the disc. The collagen fibers in the annulus fibrosus are organized in various orientations, providing the disc with strength and the ability to withstand various loads and pressures, while the elastin fibers contribute some elasticity and resilience.

Understanding the composition of the annulus fibrosus is essential for recognizing its role in spinal function and stability. Its fibrous structure helps maintain the integrity of the intervertebral disc, resisting tensile forces that occur during movement and weight-bearing activities. This design aids in distributing load evenly across the disc and protecting the vertebrae.

Other choices such as elastic fibers alone, bony structures, or a fluid-filled space do not accurately describe the annulus fibrosus. Elastic fibers are merely part of the broader composition, and the annulus is not made of bony structures or a fluid-filled space; these attributes correspond more to other anatomical aspects of the spine or intervertebral disc.