Your shoulders are where the arms connect to the body. They are formed by multiple joints, including the glenohumeral joint, sternoclavicular joint and scapulothoracic joint. Movement at the shoulder joint is complex, as it requires the coordinated muscle activity of multiple muscles to rotate and lift the arms and rotate the scapulae. The shoulder is a very mobile joint, allowing the arm to move about in multiple directions. However, with mobility comes an increased need for stability. The shoulder, due to its shallow attachment point and mobility, requires good support from the muscles and ligaments around it to stabilize the joint and prevent unwanted movement. Over time, poor posture and a lack of use or movement of the upper extremity can contribute to pain and degeneration at the shoulder joint. The shoulder can also become injured during a fall.