The subacromial space is the distance between the acromion and the humeral head. There is a clinical reference value, and the normal distance between the two is 9-10 mm, but it varies from individual to individual, and most of the clinical judgment of its abnormality is not based on the index, but needs to be combined with the patient’s clinical symptoms for plain film examination. If a patient has abnormal clinical symptoms, such as limited abduction of the shoulder joint, subacromial pressure pain, and after plain film examination, there are obvious bony bulges at the acromion and greater humeral tuberosity, as well as increased bone density, it mostly suggests the possibility of lesions. The diagnostic method often chosen in clinical practice is to take orthopantomographs of the chest and compare the affected side with the healthy side, which is the diagnostic method often chosen in clinical practice to determine whether the distance between the shoulder peak and the humeral head is normal or not. It is rarely used to diagnose the disease based on indicators.