Zanca retrospectively reviewed shoulder radiographs of 1,000 consecutive patients imaged for shoulder pain or arthritis. The question: how often is the acromioclavicular joint the source of shoulder pain, and how well do routine films show it? He compared AC joint findings against glenohumeral and periarticular disease and used a dedicated angled view.
When a patient has shoulder pain and the routine AP film looks normal, do not stop there. The AC joint sits superimposed on the acromion on standard views, so a quarter to a third of routine films cannot properly show it. That is why AC disease gets called the "forgotten joint."
The practical fix is the Zanca view: a 30-35° cephalad-angled AP with reduced exposure that throws the joint clear of the acromion. Mental model: shoulder pain plus point tenderness over the AC joint, pain on cross-body adduction, and a normal-looking glenohumeral film should push you to order a dedicated AC view.
One caution the author stresses: AC degenerative change is common with aging and can be asymptomatic, so correlate the radiograph with exam findings before blaming it for the pain.
Zanca retrospectively reviewed shoulder radiographs of 1,000 consecutive patients imaged for shoulder pain or arthritis. The question: how often is the acromioclavicular joint the source of shoulder pain, and how well do routine films show it? He compared AC joint findings against glenohumeral and periarticular disease and used a dedicated angled view.
When a patient has shoulder pain and the routine AP film looks normal, do not stop there. The AC joint sits superimposed on the acromion on standard views, so a quarter to a third of routine films cannot properly show it. That is why AC disease gets called the "forgotten joint."
The practical fix is the Zanca view: a 30-35° cephalad-angled AP with reduced exposure that throws the joint clear of the acromion. Mental model: shoulder pain plus point tenderness over the AC joint, pain on cross-body adduction, and a normal-looking glenohumeral film should push you to order a dedicated AC view.
One caution the author stresses: AC degenerative change is common with aging and can be asymptomatic, so correlate the radiograph with exam findings before blaming it for the pain.