This narrative review models the throwing shoulder as a coordinated clavicle-scapula-humerus system driven by scapulohumeral rhythm. It explains how the claviscapular segment positions the humerus and how altered mechanics (scapular dyskinesis) cause internal impingement and labral injury. It also lays out a systematic clinical evaluation pathway for the injured overhead athlete.
When a thrower presents with shoulder pain, resist the urge to jump straight to the glenohumeral joint. This review frames the shoulder as a chain: the core and ground reaction force generate over half of humeral acceleration, so hip and core weakness can manifest as shoulder dysfunction. That is why the exam pathway starts with single-leg stability testing.
The key mental model is scapular protraction. Protraction antetilts the glenoid and translates the humeral head posteriorly, producing internal impingement that damages the labrum. Correcting the scapula with the assistance and retraction tests tells you whether the scapula is driving the symptoms.
A practical shift: labral injury in throwers is more often posterior than superior, so do not anchor on a SLAP-only diagnosis. Use a combination of provocative tests and measure external rotation with the forearm pronated to reproduce the cocking position.
This narrative review models the throwing shoulder as a coordinated clavicle-scapula-humerus system driven by scapulohumeral rhythm. It explains how the claviscapular segment positions the humerus and how altered mechanics (scapular dyskinesis) cause internal impingement and labral injury. It also lays out a systematic clinical evaluation pathway for the injured overhead athlete.
When a thrower presents with shoulder pain, resist the urge to jump straight to the glenohumeral joint. This review frames the shoulder as a chain: the core and ground reaction force generate over half of humeral acceleration, so hip and core weakness can manifest as shoulder dysfunction. That is why the exam pathway starts with single-leg stability testing.
The key mental model is scapular protraction. Protraction antetilts the glenoid and translates the humeral head posteriorly, producing internal impingement that damages the labrum. Correcting the scapula with the assistance and retraction tests tells you whether the scapula is driving the symptoms.
A practical shift: labral injury in throwers is more often posterior than superior, so do not anchor on a SLAP-only diagnosis. Use a combination of provocative tests and measure external rotation with the forearm pronated to reproduce the cocking position.