Posterior-Superior Glenoid Impingement of the Throwing Shoulder: Evaluation and Management

Dale J. Buchberger, DC, DACBSP

Abstract:

The throwing shoulder is subjected to extreme forces secondary to the complex motions that occur during the act of hurling a five-ounce spherical object through space. Numerous conditions can develop as a result of chronic microtrauma to the structures surrounding the glenohumeral joint. Posterior superior glenoid impingement (PSGI) involves impingement of the articular side of the rotator cuff against the posterior superior glenoid labrum. This occurs in conjunction with an underlying subtle instability of the glenohumeral joint. The mechanism is that of abduction, maximal external rotation and horizontal extension or that mechanism which is similar to the throwing motion. Because of the complex nature of the glenohumeral joint and the surrounding structures, the examiner must be knowledgeable regarding the functional anatomy of the shoulder girdle and how it relates to the mechanisms involved in the before mentioned conditions. The purpose of this paper is to describe clinical methodology, which may assist the examiner in the diagnosis and managernent of the throwing athlete with posterior superior glenoid impingement.