A patient is performing active shoulder abduction. At 120 de…
A patient is performing active shoulder abduction. At 120 degrees of elevation, the PTA observes reduced scapular upward rotation and increased superior migration of the humeral head. The PTA determines that the patient is not demonstrating normal scapulohumeral rhythm. Which of the following best explains the expected contribution of the glenohumeral joint and scapulothoracic joint at this range?