The spine consists of 33 bones or vertebrae, 24 of which are separate bones allowing movement and 9 which are fused together. The 5 sections of the spine or vertebral column are the cervical, thoracic, lumbar, and sacrum which includes the coccyx.
Structure of the spine
- The Cervical spine makes up the neck and has 7 vertebrae. The top two bones are known as the atlas and axis and are different from the others to allow rotation of the skull as well as forwards and backward.
- The Thoracic spine has 12 vertebrae to which the ribs attach. They are larger than the cervical vertebrae as they have to support more of the body’s weight.
- The Lumbar spine has 5 vertebrae that make up the lower back.
- The Sacrum consists of 5 bones that are fused or stuck together and the coccyx is made up of 4 tiny bones and used to be a tail.
Each vertebra is separated by intervertebral discs which are flexible cartilage discs. These allow movement in the spine and have a shock-absorbing or cushioning function as well.
Each disc is made up of two parts, a tougher fibrous outside and a central substance called nucleus pulposus. When a disc is damaged (or prolapsed) it is the squidgy liquid in the middle which often squeezes out putting pressure on the spinal cord and causing pain.