Periarthritis of the shoulder is mainly caused by chronic damage and degeneration of the joint which leads to chronic wear and tear, as well as aseptic inflammation in the tendons, ligaments, and joint capsule around the shoulder joint, resulting in pain and limited mobility around the shoulder. To diagnose periarthritis of the shoulder, it is first necessary to rule out limited mobility of the shoulder joint due to trauma, such as injuries to the rotator cuff and other related conditions. Imaging studies like MRI can also be used to clarify and rule out rotator cuff injuries and other conditions, and a clear diagnosis can be made in conjunction with physical examination and etiology.