import { HighYieldBox, ExamCheatSheet, Tabs, Tab, ComparisonTable, VivaScenario, ContentSection, SpecialTestCard , MedicalImage} from '@/components/content' # Shoulder Impingement & ACJ Examination Impingement syndrome is the most common cause of shoulder pain. Examiners expect you to differentiate between subacromial (extrinsic) impingement and internal (intrinsic) impingement, understand the Neer and Hawkins tests, and recognize ACJ pathology with the cross-body adduction test. ## Quick Reference One-Pager ## Introduction **Subacromial Impingement Syndrome:** - Mechanical compression of rotator cuff under coracoacromial arch - Most common cause of shoulder pain in adults - Spectrum from tendinitis to full-thickness tears **Causes of Impingement:** - **Extrinsic**: Structural narrowing (type III acromion, AC osteophytes, os acromiale) - **Intrinsic**: Tendon degeneration, weakness, overhead activities - **Secondary**: Instability, scapular dyskinesia **ACJ Pathology:** - Common site of OA (especially in laborers, weightlifters) - May coexist with impingement - Can be primary pain generator or contribute to impingement ## Clinical Assessment **Subacromial Impingement:** - Pain with overhead activities - Night pain (lying on affected side) - Painful arc with arm elevation - Gradual onset (unless acute on chronic) - May have weakness if cuff involved **ACJ Pain:** - Pain localized to "top of shoulder" - Aggravated by cross-body reaching - Pain with overhead pressing (gym) - May have clicking or grinding ## Impingement Tests **Neer vs Hawkins:** - Both test subacromial impingement - Neer: Anterior acromion compression (pure forward flexion) - Hawkins: Coracoacromial ligament compression (flexion + IR) - Using both increases sensitivity (if either positive) ## ACJ Tests ## Internal Impingement **Definition:** - Impingement of articular surface of rotator cuff against posterosuperior glenoid - Occurs in late cocking phase of throwing **Population:** - Young overhead athletes (throwers, swimmers, tennis) - Different from subacromial impingement **Examination:** - Pain in apprehension position (90° abduction, maximum external rotation) - Posterior shoulder pain (not anterolateral like subacromial) - May have GIRD (glenohumeral internal rotation deficit) ## Differential Diagnosis ## Summary Presentation ## Impingement vs ACJ Pain ## Examiner Tips