Subacromial syndrome seems to be a more common diagnosis in general practice than in the authors' orthopaedic practice. Moreover, a first-line diagnosis of this syndrome is often not confirmed in the second line. A possible cause for this discrepancy is a difference in the manner in which abduction is performed according to the NHG guideline 'Shoulder symptoms'. The authors argue that a disorder of the acromioclavicular or sternoclavicular joint will not be detected with the current definition. Yet a correct diagnosis is important if corticosteroid injections are to be given. The authors suggest that the guideline be changed, so that abduction is performed in a different manner.