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Acromial types

The shape of the acromion had been initially divided into three types (which was known as the Bigliani classification 3), to which a fourth has been added 2.


Acromion morphology based on sagittal oblique MRI:

  1. flat inferiorly (12%6)
  2. curved (56%)
    • parallel to the humeral head with concave undersurface 
    • considered most common type 3
  3. hooked (29%)
    • most anterior portion of the acromion has a hooked shape
    • associated with increased incidence of shoulder impingement
  4. convex (upturned) (3%)
    • most recent classification of acromion process shape
    • the undersurface of the acromion is convex near the distal end 4
    • no convincing correlation between a type 4 acromion and impingement syndrome exists 4, 5

See also

Related articles

Upper limb anatomy

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