Rotator cuff tears are a common cause of shoulder pain. Clinical and radiographic findings can suggest the presence of a rotator cuff tear. The most sensitive clinical findings are impingement and the "arc of pain" sign. Radiographic findings are usually normal in the acute setting, although the "active abduction" view may show decreased acromiohumeral distance. In more chronic cases, an outlet view may show decreased opacity and decreased size of the supraspinatus muscle due to atrophy. In late cases, the humeral head may become subluxated superiorly, and secondary degenerative arthritis of the glenohumeral joint may ensue. Ultrasonography (US), with over 90% sensitivity and specificity, can help confirm the diagnosis in clinically or radiographically equivocal cases. US can also reveal the presence of other abnormalities that may mimic rotator cuff tear at clinical examination, including tendinosis, calcific tendinitis, subacromial subdeltoid bursitis, greater tuberosity fracture, and adhesive capsulitis.
RSNA, 2005.