This narrative review synthesizes recent kinematic data on how the sternoclavicular and acromioclavicular joints combine to produce scapulothoracic motion during arm elevation. It connects this coupling to trapezius and serratus anterior function. Two case examples show how to target rehabilitation to specific movement deviations in impingement patients.
When you see reduced scapular upward rotation and posterior tilt in an impingement patient, target the serratus anterior first. It carries the largest moment arm for both motions and is the mechanically most effective rehabilitation lever.
The clinical mental model to carry away: the upper trapezius attaches to the clavicle, not the scapula. Loading it to "help upward rotation" is misguided and can worsen anterior tilt through clavicular elevation coupling. Its true role is clavicular retraction.
Match the exercise to the deviation. Subacromial-type patient with excess clavicular elevation gets serratus and lower trapezius work plus downtraining of the upper trapezius. The overhead thrower with GIRD and winging gets global trapezius strengthening plus posterior capsule and pectoralis stretching.
Remember that pain at or above 90 degrees is unlikely pure compressive subacromial impingement, since the cuff footprint has already rotated past the acromion. This should temper how readily you attribute high-arc pain to subacromial compression alone.
This narrative review synthesizes recent kinematic data on how the sternoclavicular and acromioclavicular joints combine to produce scapulothoracic motion during arm elevation. It connects this coupling to trapezius and serratus anterior function. Two case examples show how to target rehabilitation to specific movement deviations in impingement patients.
When you see reduced scapular upward rotation and posterior tilt in an impingement patient, target the serratus anterior first. It carries the largest moment arm for both motions and is the mechanically most effective rehabilitation lever.
The clinical mental model to carry away: the upper trapezius attaches to the clavicle, not the scapula. Loading it to "help upward rotation" is misguided and can worsen anterior tilt through clavicular elevation coupling. Its true role is clavicular retraction.
Match the exercise to the deviation. Subacromial-type patient with excess clavicular elevation gets serratus and lower trapezius work plus downtraining of the upper trapezius. The overhead thrower with GIRD and winging gets global trapezius strengthening plus posterior capsule and pectoralis stretching.
Remember that pain at or above 90 degrees is unlikely pure compressive subacromial impingement, since the cuff footprint has already rotated past the acromion. This should temper how readily you attribute high-arc pain to subacromial compression alone.