Acromiohumeral interval

Dr Daniel J Bell 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. 

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

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
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Article information

rID: 30619
Section: Approach
Synonyms or Alternate Spellings:
  • 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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