Cadaveric study using stereophotogrammetry and radiography in 9 fresh-frozen shoulders to map where and when the rotator cuff contacts the acromion during simulated arm elevation. Answers what the impingement arc actually looks like in three dimensions — data that plain radiographs cannot provide.
Before this paper, the rationale for anterior acromioplasty rested on Neer's 2D radiographic observations and cadaveric inspection. This study provided the first 3D quantitative map of subacromial contact, confirming that impingement is strictly an anterior phenomenon at every point in the arc.
When you order a shoulder outlet view to assess acromial morphology, this is the paper behind that decision. Type III acromions narrow the anterior subacromial space structurally, and this study shows they produce greater contact at every elevation angle tested — not just at peak arc.
For the young throwing athlete with posterior shoulder tightness or subtle instability, this paper explains the mechanism: reduced external rotation keeps the greater tuberosity under the anterior acromion longer, increasing compressive load on the cuff. Posterior capsule stretching is not just rehabilitation filler. It directly reduces subacromial contact mechanics.
One nuance worth knowing: standard AP radiographs measure bone-to-bone interval and can appear normal even when the cuff tendon is being compressed against the acromion. A patient with mid-arc pain and a 'normal' AHI on X-ray may still have meaningful soft tissue impingement.
Cadaveric study using stereophotogrammetry and radiography in 9 fresh-frozen shoulders to map where and when the rotator cuff contacts the acromion during simulated arm elevation. Answers what the impingement arc actually looks like in three dimensions — data that plain radiographs cannot provide.
Before this paper, the rationale for anterior acromioplasty rested on Neer's 2D radiographic observations and cadaveric inspection. This study provided the first 3D quantitative map of subacromial contact, confirming that impingement is strictly an anterior phenomenon at every point in the arc.
When you order a shoulder outlet view to assess acromial morphology, this is the paper behind that decision. Type III acromions narrow the anterior subacromial space structurally, and this study shows they produce greater contact at every elevation angle tested — not just at peak arc.
For the young throwing athlete with posterior shoulder tightness or subtle instability, this paper explains the mechanism: reduced external rotation keeps the greater tuberosity under the anterior acromion longer, increasing compressive load on the cuff. Posterior capsule stretching is not just rehabilitation filler. It directly reduces subacromial contact mechanics.
One nuance worth knowing: standard AP radiographs measure bone-to-bone interval and can appear normal even when the cuff tendon is being compressed against the acromion. A patient with mid-arc pain and a 'normal' AHI on X-ray may still have meaningful soft tissue impingement.