intervertebrali

Intervertebral discs are fibrocartilaginous cushions located between adjacent vertebrae along the spine, from the cervical to the lumbar regions. They function as joints and shock absorbers, distributing loads, enabling a range of spinal motions, and helping maintain intervertebral height.

Each disc consists of two main parts: an outer ring called the annulus fibrosus and an inner gel-like core called the nucleus pulposus. The annulus fibrosus is formed by several lamellae of collagen, while the nucleus pulposus is rich in proteoglycans and water. The discs are bounded by cartilage endplates. The discs are largely avascular; nutrition reaches the disc mainly by diffusion from the adjacent endplates. The outer annulus is innervated, which explains why disc pathology can be painful, whereas the nucleus pulposus is largely insensate.

Functionally, intervertebral discs absorb compressive forces, permit motion between vertebrae, and contribute to spinal height. With aging and repetitive loading, discs undergo degenerative changes: loss of water content, fissures in the annulus, and reduced height, which can lead to reduced mobility and pain.

Pathology commonly involves disc degeneration and herniation. A herniated disc occurs when the nucleus pulposus protrudes through a damaged annulus, often compressing nearby nerve roots. In the lumbar region, this frequently affects the L4–L5 or L5–S1 levels and can cause radicular pain and neurologic symptoms.

Diagnosis relies on clinical evaluation and imaging, with MRI as the preferred modality. Treatment ranges from conservative management (rest, physical therapy, NSAIDs) to injections or surgical procedures such as discectomy or fusion for persistent or severe cases.