Humeral Head Retroversion in Competitive Baseball Players and Its Relationship to Glenohumeral Rotation Range of Motion

Design Prospective case series. Objective To determine if an osseous component in the form of increased humeral head retroversion may contribute to observed differences in the amount of rotation between the throwing and nonthrowing shoulders of competitive baseball players. Background Differences in side-to-side shoulder rotation range of motion (ROM) are seen in throwing athletes. In the past, these differences have been attributed to adaptive changes to the surrounding soft tissue structures, including attenuation of the anteroinferior capsule and ligaments, and tightening of the posterior capsule. Recent studies, however, suggest that a possible osseous adaptation in the form of increased humeral head retroversion may be the cause of this side-to-side ROM difference. Methods and Measures Twenty-five individuals (19 competitive baseball players, 6 controls with no history of specific overhead sports activity) with no previous shoulder surgery and free of any symptomatic shoulder pathology at the time of...