Region

Shoulders

Regio deltoidea

The shoulder is not one joint but a complex — the ball-and-socket glenohumeral joint, the collarbone joints at each end, and the shoulder blade gliding on the ribcage — draped in the deltoid and driven by the rotator cuff. That arrangement buys the arm more range than anywhere else in the body, and pays for it with the least bony stability. People come to a therapist for the shoulder because of pain reaching overhead or behind the back, night pain lying on it, weakness after a strain, and the stiffness that sets in once the joint has been guarded for a while.