Imaging Study of Acromioclavicular Joint Injury / 实用放射学杂志

ABSTRACT

Objective To study the imaging findings of the normal acromioclavicular joint and acromioclavicular dislocation.Methods CR films of normal shoulder in 68 cases and normal chest in 400 cases were collected.The distances of the acromioclavicular joint were measured,and the inferior cortex line of the acromioclavicular joint was observed on CR.MRI in 30 cases with normal shoulder,24 cases with acromioclavicular dislocation and 7 cases with shoulder impingement syndrome were also presented.Results The normal distance of the acromioclavicular joint was (3.36±0.44) mm.There was an arch line on the inferior cortex of the acromioclavicular joint for normal subjects.According to the Rockwood classification,acromioclavicular dislocation included type Ⅰ in 7/24 cases,type Ⅱ in 5/24 cases and type Ⅲ in 12 cases.The distances of the acromioclavicular joint were increased(＞4.3 mm) in type Ⅱ and type Ⅲ,and the inferior cortex lines of the acromioclavicular joint were not continual in type Ⅲ.MR imaging showed that the intra-articular fibrocartilaginous disk,the capsular and acromioclavicular ligament structure were ruptured in type Ⅱ,and coracoclavicular ligament torn in type Ⅲ.Conclusion The distance and the inferior cortex line of the acromioclavicular joint are of important value in diagnosis and classification of acromioclavicular dislocation.MRI is the most significant method in diagnosis of acromioclavicular dislocation.