Acromioclavicular Joint: The gliding joint formed by the outer extremity of the CLAVICLE and the inner margin of the acromion process of the SCAPULA.DislocationsClavicle: A bone on the ventral side of the shoulder girdle, which in humans is commonly called the collar bone.Shoulder Dislocation: Displacement of the HUMERUS from the SCAPULA.Acromion: The lateral extension of the spine of the SCAPULA and the highest point of the SHOULDER.Visual Analog Scale: A subjective psychometric response scale used to measure distinct behavioral or physiological phenomena based on linear numerical gradient or yes/no alternatives.Shoulder Impingement Syndrome: Compression of the rotator cuff tendons and subacromial bursa between the humeral head and structures that make up the coracoacromial arch and the humeral tuberosities. This condition is associated with subacromial bursitis and rotator cuff (largely supraspinatus) and bicipital tendon inflammation, with or without degenerative changes in the tendon. Pain that is most severe when the arm is abducted in an arc between 40 and 120 degrees, sometimes associated with tears in the rotator cuff, is the chief symptom. (From Jablonski's Dictionary of Syndromes and Eponymic Diseases, 2d ed)Shoulder Joint: The articulation between the head of the HUMERUS and the glenoid cavity of the SCAPULA.Shoulder Pain: Unilateral or bilateral pain of the shoulder. It is often caused by physical activities such as work or sports participation, but may also be pathologic in origin.Rotator Cuff: The musculotendinous sheath formed by the supraspinatus, infraspinatus, subscapularis, and teres minor muscles. These help stabilize the head of the HUMERUS in the glenoid fossa and allow for rotation of the SHOULDER JOINT about its longitudinal axis.Scapula: Also called the shoulder blade, it is a flat triangular bone, a pair of which form the back part of the shoulder girdle.Shoulder: Part of the body in humans and primates where the arms connect to the trunk. The shoulder has five joints; ACROMIOCLAVICULAR joint, CORACOCLAVICULAR joint, GLENOHUMERAL joint, scapulathoracic joint, and STERNOCLAVICULAR joint.Reconstructive Surgical Procedures: Procedures used to reconstruct, restore, or improve defective, damaged, or missing structures.Orthopedic Procedures: Procedures used to treat and correct deformities, diseases, and injuries to the MUSCULOSKELETAL SYSTEM, its articulations, and associated structures.Ligaments, Articular: Fibrous cords of CONNECTIVE TISSUE that attach bones to each other and hold together the many types of joints in the body. Articular ligaments are strong, elastic, and allow movement in only specific directions, depending on the individual joint.Range of Motion, Articular: The distance and direction to which a bone joint can be extended. Range of motion is a function of the condition of the joints, muscles, and connective tissues involved. Joint flexibility can be improved through appropriate MUSCLE STRETCHING EXERCISES.Joints: Also known as articulations, these are points of connection between the ends of certain separate bones, or where the borders of other bones are juxtaposed.