If you want to judge whether it is acromioclavicular impingement syndrome, you can mainly start from the clinical manifestations and auxiliary examination. 1. Clinical manifestations: when the patient’s shoulder joint moves forward or anterolateral between 60 degrees and 120 degrees, there is limited pain in the shoulder, the position is fixed, and there is pressure and pain at the outer edge of the acromion; when the arm is rotated internally and externally, especially when it is abducted to between 70 degrees and 120 degrees, there is obvious pain. 2. Auxiliary examination: mainly for imaging examination, X-ray can see that the acromion has bony encumbrance due to osteophytes; MRI can see tissue edema and tendon damage. In addition, if repeated impingement occurs, the shoulder ligaments may tear and cause pain and osteophytes, so it should also be combined with the patient’s medical history and other related examinations to make a comprehensive judgment.