A disc is the soft pad positioned in between each of the vertebrae of the spine. The vertebral disc acts as a spacer, shock absorber, and part of the cartilaginous joints that allow movement in the spine.
The disc can withstand compression and other stresses, while allowing a great deal of movement and flexibility. Intervertebral discs are composed of two parts: a tough outer portion (annulus fibrosus) and a softer inner core (nucleus pulposus).
The annulus fibrosus and the nucleus pulposus fit together like two concentric cylinders and the configuration can be described as like a jelly doughnut. There are a total of twenty-three vertebral discs in the spinal column.