Acromioclavicular joint (Zanca view)

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The Zanca view is a specialized projection of the acromioclavicular joint (ACJ), which will better demonstrate the acromioclavicular joint free from superimposition and aid in the assessment of distal osteophytes.

Indications

The Zanca view is used in the assessment of acute and chronic acromioclavicular joint injuries.  The view optimizes visualization of the acromioclavicular joint, as overlying structures can limit assessment in an AP projection, with distal osteophytes better visualized.

Patient position

  • patient is erect
  • midcoronal plane of the patient is parallel to the image receptor, in other words, the patient's back is against the image receptor
  • acromioclavicular joint of the affected side is at the center of the image receptor
  • affected arm is in a neutral position by the patient side

Technical factors

  • anteroposterior projection
  • centering point
    • at the acromioclavicular joint with a 10-15 cephalad angle 
  • collimation
    • superior to the skin margins
    • inferior to the humeral head
    • lateral to include the skin margin
    • medial to lateral third of the clavicle
  • orientation  
    • landscape
  • detector size
    • 18 cm x 24 cm
  • exposure
    • 40-50 kVp
    • 10-15 mAs
  • SID
    • 100 cm
  • grid
    • no 

Image technical evaluation

  • the acromioclavicular joint is free from superimposition 

Practical points

The differences between this projection and a standard AP are the cephalic angle and the decrease in kVp.