The patient was a 19-year-old male soldier. While participating in a military training exercise, he experienced a dislocation and strain in his left shoulder (Fig. 3.1). The manual reduction procedure lasted for a period of 3 months. The individual resumed combat training but subsequently reported increasing numbness and pain below the left shoulder joint, along with difficulty in applying force when lifting objects. An MRI examination of the shoulder joint revealed abnormal signal at the attachment site of the supraspinatus muscle of the left shoulder to the greater tuberosity of the humerus (Fig. 3.2). The patient was admitted to the hospital with rotator cuff injury and was scheduled for surgical treatment.