Intervertebral discs are fibro-cartilaginous discs that lie between the vertebral bodies of the vertebrae of the cervical, thoracic, and lumber regions of the body. Their primary purpose is to provide shock absorption between adjacent vertebrae.

Each disc is composed two main layers: an outer fibrous layer made of concentric layers of fibrocartilage, referred to as the annulus fibrosis; and an inner soft, gelatinous layer called the nucleus pulposus.

Figure 1: Parts of an intervertebral disc.