The throwing shoulder in pitchers frequently exhibits a paradox of glenohumeral joint motion, in which excessive external rotation is present at the expense of decreased internal rotation. The object of this study was to determine the role of humeral head retroversion in relation to increased glenohumeral external rotation. Glenohumeral joint range of motion and laxity along with humeral head and glenoid version of the dominant versus nondominant shoulders were studied in 25 professional pitchers and 25 nonthrowing subjects. Each subject underwent a computed tomography scan to determine bilateral humeral head and glenoid version. The throwing group demonstrated a significant increase in the dominant shoulder versus the nondominant shoulder in humeral head retroversion, glenoid retroversion, external rotation at 90 degrees, and external rotation in the scapular plane. Internal rotation was decreased in the dominant shoulder. Total range of motion, anterior glenohumeral laxity, and posterior glenohumeral laxity were found to be equal bilaterally. The nonthrowing group demonstrated no significant difference in humeral head retroversion, glenoid retroversion, external rotation at 90 degrees or external rotation in the scapular plane between shoulders, and no difference in internal rotation at 90 degrees, total motion, or laxity. A comparison of the dominant shoulders of the two groups indicated that both external rotation at 90 degrees and humeral head retroversion were significantly greater in the throwing group.

Objective: To describe several clinical tests and predisposing factors for shoulder impingement syndrome in violin and viola players. Subjects: Ten musicians (7 females, 3 males) and 18 controls (8 females, 10 males), all college-aged. Methods: Subjects were interviewed about their music-playing history and shoulder pain. Four clinical assessment tests were performed on both shoulders: Neer impingement text (maximal flexion +/- pain), shoulder internal rotation with over-pressure (end-feel and +/- pain), lower trapezius muscle strength (ft-lbs of torque from manual dynamometer), and forward shoulder posture (height of acromion from plinth with subject supine). Analysis: Descriptive analysis of questionnaire data, plus two-sample t-tests for manual shoulder assessment tests in musicians versus controls. Also comparisons of music-playing history in musicians with and without shoulder impingement. Results: Seventy percent of musicians reported pain somewhere in the upper limb, with 50% in the left shoulder and 30% in the right shoulder. Thirty percent of musicians had a positive Neer impingement test, while 0% of controls did. There was a significant phi (Φ) correlation between being a musician and having a higher incidence of shoulder impingement (p<0.01 for bowing arm, p<0.05 for left arm). Those musicians with a positive impingement test also had pain with over-pressure in internal rotation, indicating a chronic condition. Musicians' mean playing time was 9.8 hr/wk, with 14 min/hr of rest. Musicians with impingement tended to play more hours per week, but differences in playing time and rest were not significant. t-Tests showed no significant difference in lower trapezius strength or degree of forward shoulder between musicians and controls. Conclusions: Upper string players are at increased risk for shoulder impingement.

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