CONTRIBUTION OF AXIAL ARM ROTATION TO HUMERAL HEAD TRANSLATION

The contribution of axial arm rotation to translation of the humeral h ead with the arm in the hanging position was examined using nine fresh -frozen cadaveric shoulders. Three standard clinical tests were simula ted: anterior and posterior translation and sulcus tests. In both the anterior translation and sulcus tests, anterior and inferior displacem ents were significantly restricted in internal rotation but not in neu tral and external rotation. In the posterior translation test, no sign ificant differences in displacement could be observed in internal, neu tral, or external rotation. Since anterior and inferior translations o f the humeral head were significantly affected by the rotation of the arm, we recommend that the anterior translation and sulcus tests be pe rformed in various rotations.