Pathophysiology of anterior shoulder instability.

OBJECTIVE To review some of the important biomechanical factors that provide glenohumeral stability, along with the pathologic mechanisms involved in glenohumeral instability of the shoulder. DATA SOURCES Current English medical literature concerning the multiple pathologic factors involved in glenohumeral instability was reviewed. DATA SYNTHESIS Multiple dynamic and static factors control glenohumeral instability. Knowledge of normal shoulder anatomy and biomechanics is necessary to interpret pathologic events. CONCLUSIONS/RECOMMENDATIONS Dynamic and static factors collectively provide stability to the glenohumeral joint. Disruption or malfunction of these factors causes dysfunction in the shoulder.