Joint dysfunction is a loss in joint motion. The body is designed to have certain amounts of motion at each vertebral level. For example, the thoracic spine has twelve bones in its region. If a loss in joint motion is found between the T6 and T7 level the joints above and below will move more freely (hyper-mobile) to compensate for the loss of motion between the two levels. This loss is joint motion (hypomobility) if not treated may predispose the segment to advancement in arthritic changes.