Acromioclavicular joint series

The acromioclavicular (AC) joint radiographic series is used to evaluate the acromioclavicular joint and the distal clavicle.

Indications

AC radiographs are performed for a variety of indications including: 

• shoulder trauma
• direct blows to the should region
• following a fall onto adducted arm
• suspected dislocation
• suspected arthritis

Projections

Standard projections

• AP view
  • erect view demonstrating the AC joint in the anteroposterior plane
  • best view to inspect widening of the AC joint

Additional projections

• AP with weight bearing
  • also known as a stress view, the patient holds onto a weight on the affected side, placing inferior pressure on the AC joint
  • this view is used to rule out displacement when it is suspected yet not confirmed on the AP view
• AP comparison views
  • both AC joints are imaged separately, to rule out a suspected displacement or differentially anatomical variation
• Zanca view
  • AP projection with a 10-15 degree cephalad angle to free the AC joint from superimposition