25/02/2026
Scapular mechanics are central to efficient shoulder function and load sharing across the upper kinetic chain.
The scapula and clavicle move synchronously through the sternoclavicular and acromioclavicular joints, with the clavicle acting as a dynamic strut linking the axial skeleton to the upper limb. This coordinated motion allows the glenoid to maintain optimal alignment with the humeral head during arm elevation and functional loading.
• Upward/downward rotation** – orienting the glenoid to support humeral elevation and load transfer
• Protraction/retraction** – controlling thoracic positioning and force transmission
• Elevation/depression** – assisting with clavicular and scapular load distribution
• Posterior tilt and external rotation** – maintaining subacromial space and joint centration
The sternoclavicular joint provides substantial motion (elevation/depression, protraction/retraction, and axial rotation), enabling the clavicle and scapula to move as a coordinated unit. The acromioclavicular joint fine-tunes this motion with rotational adjustments that can reach up to ~40–50° during full elevation.
When scapulohumeral rhythm becomes disrupted, joint centration and load distribution are compromised. This can reduce subacromial space, increase strain on periarticular tissues, and contribute to impingement, rotator cuff overload, and cervicothoracic compensation
Effective rehabilitation should emphasise:
• Scapular positioning and control
• Serratus anterior and lower trapezius force coupling
• Thoracic mobility
• Endurance of periscapular stabilisers
