Annulus fibrosus

Annulus fibrosus is a component of the intervertebral disc, which is located between the vertebrae in the spine. It is a ring-like structure that surrounds the nucleus pulposus, providing strength and flexibility to the spine.

Structure

The annulus fibrosus is composed of several layers, or lamellae, of fibrocartilage. These layers are made up of water, collagen, and proteoglycans. The collagen provides strength and structure, while the proteoglycans attract and hold water, providing resistance to compression.

Function

The primary function of the annulus fibrosus is to contain the nucleus pulposus, preventing it from herniating or leaking out of the disc space. It also serves as a ligament that connects the vertebrae together, providing stability to the spine. Additionally, the annulus fibrosus has a role in transmitting loads across the vertebral column.

Clinical significance

Damage or degeneration of the annulus fibrosus can lead to a number of spinal conditions. These include disc herniation, where the nucleus pulposus leaks out through tears in the annulus fibrosus, and degenerative disc disease, where the annulus fibrosus becomes weakened or damaged over time. Both conditions can cause pain and other symptoms, depending on the location and severity of the damage.

See also

• Intervertebral disc
• Nucleus pulposus
• Spine
• Vertebrae