There are two main reasons for the rattle of bones in the back area. The first is due to joint instability in the synovial joints of the back. When the head is tilted back and the shoulder is shrugged, the joint instability will be reset, so that the friction between the articular cartilage and the articular cartilage will be squeezed and there will be a noticeable ringing sound. The second condition is when the shoulder joint is rotated so that there is significant movement of the scapula. The muscular attachment points around the scapula, such as the scapularis and rhomboid muscles, will produce a plucking force on the bone when moving. Because of inflammation, strain and degeneration of these soft tissues, the elasticity of the muscles and soft tissues may be reduced. In the activity will produce a plucking with the bone, the back bone sound.