Lateral roentgenographic projections of the acromioclavicular joint.

Although the acromioclavicular joint is frequently injured in both contact and noncontact sports, the treatment is nonspecific, as demonstrated by the numerous methods of treatment currently employed. Despite treatment, some shoulders still develop chronic symptoms and disability during overhead lifting, throwing, and swinging. Perhaps these difficulties develop as a result of an incomplete evaluation of the joint and because the exact nature of the injury is not appreciated. Therefore, the shoulder develops chronic problems. We have routinely utilized a lateral roentgenogram of the acromion to evaluate the acromioclavicular joint. This has significantly aided us in the diagnosis and treatment of acromioclavicular joint injuries, especially when there was posterior dislocation of the distal clavicle. This presentation reviews standard roentgenography of the acromioclavicular joint and illustrates the method of obtaining the lateral projection as described by O. M. Alexander. We will also show how this method has helped us clinically in detecting posterior dislocations of the distal end of the clavicle.