THE SPINE
Anatomy > Intervertebral Discs
The vertebrae are separated by intervertebral discs which act as cushions or shock-absorbers between the bones. Each disc is made up two parts - an tough outer layer called the annulus surrounding a liquid centre called the nucleus pulposus.
Each disc is identified according to the vertebrae above and below it. Thus, the topmost disc in the spine is known as C1-C2 and so on, through C7-T1 (the junction of the cervical and thoracic spines) down to the last of the discs, L5-S1 where the lumbar spine joins the sacrum.