The shoulder is the most moveable joint in the body. It is however, an unstable joint because of the range of motion allowed.
This instability increases the likelihood of joint injury, often leading to a degenerative process, in which tissues break down and no longer function well.
The shoulder must be mobile enough for the wide range actions of the arms and hands, but also stable enough to allow for actions such as lifting, pushing and pulling.
Major injuries to the shoulder include rotator cuff tear and bone fractures of one or more of the bones of the shoulder.