SUPERIOR MIGRATION OF THE HUMERAL HEAD

Abstract

1. A radiological study of the acromio-humcral interval in sixty normal shoulders and in fifty-nine shoulders with known tears of the rotator cuff is reported. 2. The normal acromio-humeral interval was found to be seven to fourteen millimetres, a range that is consistent with previous observations. 3. Narrowing of this interval is a frequent concomitant of a tear of the rotator cuff. 4. An interval of five millimetres or less should be considered compatible with a tear of the rotator cuff until proven otherwise. 5. An explanation of the pathomechanics of the observation has been proposed.