The backbone, or spine, supports the weight of the upper body and makes movement possible. Because the spine is involved in nearly every movement the body makes, it is particularly vulnerable to injury and pain.

The spine consists of a stack of spool-like bones called vertebrae that forms a column reaching from the base of the skull down to the hip area. The spine is divided into five sections: cervical, thoracic, lumbar, sacrum, and coccyx.

The cervical spine contains the first seven vertebrae in the neck. Below that is the thoracic spine, which contains the twelve vertebrae of the upper back, then the lumbar spine, which contains the five lower back vertebrae. At the base of the lumbar spine is the sacral spine, or sacrum, which is made up of five additional vertebrae that have fused together. At the very end of the spine is the tailbone, or coccyx, which consists of four (or, in some people, five) small vertebrae.

Discs sit between the vertebrae to separate the bones and keep them from scraping against one another. These discs have a gel-like core that acts as a cushion to absorb the shocks and jolts that come with movement. The core is surrounded by a jacket of tough fibrous material that keeps the gel in place.

The vertebrae are linked together with bony knobs that form joints called facet joints. These joints allow the vertebrae to move and give the spine flexibility.

The spinal cord runs down the centre of the spinal column, carrying the nerve impulses that permit movement and transmitting sensations such as pain.

The whole structure of the back is held together with a network of muscles, tendons, and ligaments. Working together, these various parts allow us to walk, sit, work, and play.