MR findings in asymptomatic shoulders: a blind analysis using symptomatic shoulders as controls.

We performed a blind prospective analysis of the shoulders of 20 asymptomatic volunteers, aged 25 to 55 years, to determine the frequency of magnetic resonance (MR) findings considered abnormal in symptomatic patients. Twenty symptomatic patients were used as controls. With regard to the asymptomatic shoulders, all 20 had intact rotator cuff tendons, although six (30%) of the tendons had abnormal internal signal, and one (5%) had abnormal morphology. Subdeltoid and subacromial fat planes were intact in 20 (100%) and 19 (95%) shoulders respectively. Subdeltoid or subacromial fluid was not present in any shoulder. Acromioclavicular osteophytes and supraspinatus depression were seen in seven (35%) and six (30%) respectively. The glenoid labrum was intact in all volunteers, although it had abnormal internal signal in 10 (50%). MR findings of abnormal signal in the glenoid labrum, and of abnormal signal and morphology of the rotator cuff tendons, supraspinatus depression, and acromioclavicular osteophytes have been reported as signs of instability, tendinitis, and impingement. Similar findings were seen in asymptomatic volunteers, indicating that these findings may not be a sign of clinically significant pathology.