The spine is the central support for the body. Another word for the spine is the backbone. The spine is made of separate irregular bones called vertebrae. The vertebrae are made up of spongy or cancellate bone surrounded by a layer of compact bone. In between each vertebrae is a layer of cartilage that keeps the bones from rubbing against each other.

There are twenty six vertebrae in the spine. Although each vertebrae can only move a little bit, the total spine is very flexible. The spine of a human being is curved. Most other mammals have a straight spine. The curves allow the spine to support and balance the body on only two legs.

Many people develop back problems as they get older. The discs start to wear away. The vertebra come out of place causing pain. The back gets stiff and makes it difficult to move.