What is the function of annulus?

1. Support and Protection:

The annulus fibrosus provides structural support and protection for the spinal cord and nerve roots. It plays a crucial role in maintaining the integrity of the intervertebral discs and helps prevent the soft, gelatinous nucleus pulposus from bulging or herniating.

2. Load Distribution:

The annulus fibrosus helps distribute the load and forces applied to the spine. It acts as a shock absorber, transmitting and distributing axial loads more evenly across the vertebral column. By doing so, it reduces the amount of stress experienced by the spinal cord, nerve roots, and other spinal structures.

3. Flexibility and Range of Motion:

The annulus fibrosus contributes to the flexibility and range of motion of the spine. Its collagenous fibers allow for controlled bending, twisting, and rotational movements of the vertebrae. The annulus facilitates the spine's ability to move while providing stability and preventing excessive or abnormal movements.

4. Joint Stability:

The annulus fibrosus, along with other components of the intervertebral disc, helps maintain joint stability between adjacent vertebrae. It reinforces the disc and prevents it from bulging or deforming under various loading conditions. By enhancing the stability of the spinal segments, the annulus fibrosus reduces the risk of spinal instability, misalignments, or subluxations.

5. Nutrition and Metabolism:

The annulus fibrosus plays a role in the nutrition and metabolism of the intervertebral discs. It allows the diffusion of nutrients and fluids from the surrounding tissues into the avascular (blood vessel-free) inner portion of the disc. The annulus helps maintain the proper biochemical environment necessary for the health and functionality of the disc.