Injuries to the shoulder can involve the scapula (shoulder blade), clavicle (collarbone) or humerus (upper arm bone), as well as the 3 joints of the shoulder: the glenohumeral, acromioclavicular and sternoclavicular joints. In addition, muscles, ligaments, tendons and nerves can be affected by an injury to the shoulder. Common shoulder injuries include: • Scapula fractures (broken shoulder blade) • Clavicle fractures (broken collarbone) • Proximal humerus fracture (break of the upper arm in the shoulder joint) • Rotator cuff injuries • Acromioclavicular joint separation (separated shoulder) • Glenohumeral joint dislocation (dislocated shoulder) • Deltoid muscle injuries and sub-deltoid bursa injuries • Injuries to the glenoid, acromion and coracoid joints Rotator cuff injuries involve one of the most important, complex areas of the shoulder, as well as the muscles and tendons holding the shoulder joint together. The rotator cuff allows the arm to reach overhead. When the rotator cuff is injured, people may not recover their full range of motion. Cumulative trauma injuries may also affect the shoulders. Repetitive motions such as lifting or carrying heavy items or operating machinery can cause these injuries. A cumulative trauma injury can cause pain, tingling, burning, discomfort, numbness or reduced range of motion that may be significant enough to prevent you from doing your job or performing day-to-day activities.