Over the past ten years ultrasound (US) has become popular in the evaluation of shoulder disorders. It allows for the detailed assessment of a wide range of changes involving different anatomic structures of the shoulder joint, including rotator cuffs, biceps tendon, and subdeltoid bursa. Koh et al found among 33 PD patients, 22 patients had abnormal US findings on the dominant side, and all 22 patients with abnormal US finding had a tendon tear and 9 patients had frozen shoulder. However, there were no control group in Koh' s study, and diagnosis of frozen shoulder with US findings is still controversial.