Scapulothoracic Dyskinesis and Anterior Shoulder Instability

Scapular dyskinesia refers to altered scapular motion or position. Specifically, it may include static or dynamic medial border prominence of the scapula, inferior angle prominence and/or premature elevation of the scapular, and accelerated inferior scapular rotation while lowering the arm. It generally occurs due to muscle imbalance/weakness or as a response to shoulder injury—including glenohumeral instability. Prevalence of scapular dyskinesis is 61% in overhead athletes and 33% in non-overhead athletes. Assessment should include a detailed physical examination including scapula-specific tests: the scapular assistance test (SAT) and scapular retraction test (SRT). Investigations (imaging and nerve conduction studies) should be targeted to identify any underlying shoulder pathology that may be a cause of dyskinesis. The mainstay of treatment for scapular dyskinesis is appropriate treatment of the underlying cause, followed by a supervised physiotherapy program focusing on re-establishing normal scapular motion and stability.