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Acromiohumeral interval

Dr Yuranga Weerakkody and Dr Henry Knipe et al.

Acromiohumeral interval is a useful and reliable measurement on AP shoulder radiographs and when narrowed is indicative of rotator cuff tear or tendinopathy. 

The shortest distance is measured. 

  • true AP shoulder radiograph
  • measure from the cortical bone at the inferior aspect of the acromion to the humeral head 3
  • can also be performed on coronal and sagittal oblique T1 MR images
  • inferior aspect of the acromion (marked by black line directly above the humeral head) directly inferiorly to the center of the subchondral cortex of the humeral head 3

Measurements of the acromiohumeral interval in the following intervals are suggestive of pathology 1,2:

Article information

rID: 30619
Section: Approach
Synonyms or Alternate Spellings:
  • Subacromial distance
  • Acromio-humeral interval (AHI)
  • Acromion humeral interval
  • Acromiohumeral space
  • Acromiohumeral distance
  • Acromio-humeral interval

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Cases and figures

  • Case 1: normal
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  • Case 2: reduced in chronic rotator cuff tear
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  • Case 3: increased in lipohemarthrosis
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