Shoulder depression pits are related to many factors, which may be caused by physiological factors or traumatic factors, so it is recommended to take corresponding treatment measures according to the causes of shoulder depression pits. 1. Physiological factors: mainly due to excessive thinning, resulting in ligamentous laxity in the shoulder area, causing instability of the acromioclavicular joint, resulting in greater mobility of the shoulder joint, which may appear in the performance of the shoulder sunken pits. At this time, it is a physiological phenomenon and generally does not need special treatment. 2. Traumatic factors: mainly due to the old injury causing shoulder capsule laxity. At the same time, when the acromioclavicular joint is dislocated due to violent impact, the clavicle end of acromioclavicular joint will bulge upward against the skin, and a sunken pit will be formed locally in the shoulder. At this time, pressing with the finger will buckle the end and be able to press down, called the piano key sign. It is recommended to seek medical attention for X-ray examination to determine the cause of the shoulder depression and to reset it promptly, if necessary by incision. In the presence of shoulder capsular laxity due to old injury, capsular tightening is recommended to facilitate recovery.