During upward rotation, which joint primarily contributes the greater amount of movement?

During upward rotation, which joint primarily contributes the greater amount of movement?

• A. Glenohumeral joint
• B. Scapulothoracic joint
• C. Clavicle
• D. Sternoclavicular joint

Answer: (A)

The main movement seen when the arm lifts upward largely comes from the glenohumeral joint. The ball-and-socket setup between the humerus and the scapula lets the arm rotate and elevate through a big arc, so this joint provides the majority of the angular displacement during upward elevation. The scapulothoracic articulation then positions the scapula on the thorax to allow that full range, and the clavicular joints (sternoclavicular and acromioclavicular) adjust the clavicle to support that motion. So while the scapulothoracic system and the clavicle contribute to enabling the movement, the glenohumeral joint supplies the greater amount of upward rotation.

The main movement seen when the arm lifts upward largely comes from the glenohumeral joint. The ball-and-socket setup between the humerus and the scapula lets the arm rotate and elevate through a big arc, so this joint provides the majority of the angular displacement during upward elevation. The scapulothoracic articulation then positions the scapula on the thorax to allow that full range, and the clavicular joints (sternoclavicular and acromioclavicular) adjust the clavicle to support that motion. So while the scapulothoracic system and the clavicle contribute to enabling the movement, the glenohumeral joint supplies the greater amount of upward rotation.