If the shoulder joint is damaged in all directions due to frozen shoulder, the arm cannot be carried to the back and the arm is not functioning properly. Second, rotator cuff tears, when the supraspinatus and anterior rotator muscle of the rotator cuff are torn or ruptured, it can lead to dysfunction of the internal rotation of the arm, which can lead to the inability to carry the arm to the back, then it is necessary to have an early checkup and examination and an early MRI to confirm the diagnosis.