Disruption of the acromioclavicular ligaments results in loss of alignment of the clavicle and acromion inferior surfaces
Additional disruption of the coracoacromial ligament results in separation of the entire scapula from the clavicle
Low grade ligament injury may not be visible on a plain X-ray
The acromioclavicular joint can be assessed with standard shoulder X-rays.
Loss of alignment of the inferior surfaces of the clavicle and acromion indicates disruption of the acromioclavicular ligaments at the acromioclavicular joint (ACJ).
Minor ligamentous disruption may not be detectable on a plain radiograph as alignment is not lost.
More severe injury can result in additional disruption of the coracoclavicular ligaments.
The inferior margins of the acromion and clavicle are well aligned (red lines) indicating integrity of the acromioclavicular ligaments (not visible - position shown by blue lines)
The coracoid is not widely separated from the clavicle - this indicates integrity of the coracoclavicular ligaments (not visible - position shown by orange lines)
