Trauma X-ray - Upper limb
Acromioclavicular joint

Key points

  • 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.

Acromioclavicular joint (ACJ) - Normal

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Acromioclavicular joint (ACJ) - Normal

  • 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)

Acromioclavicular joint disruption

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Acromioclavicular joint disruption

  • The inferior surfaces of the clavicle and acromion are not aligned - indicating disruption of the acromioclavicular ligaments
  • The coracoclavicular distance is also wide - indicating coracoclavicular ligament injury