An anthropometric study of the bilateral anatomy of the humerus.

The purpose of this study was to describe the extramedullary humeral morphology in paired humeri to determine whether geometric differences exist from side to side in the same individual. The anatomic characteristics of 28 paired, dry cadaveric humeri were measured by use of an electromagnetic tracking system. Of the characteristics examined, only the humeral head height was significantly different between right and left humeri in the same individual (P < .005). Most of the characteristics had excellent intra-specimen repeatability. In conclusion, there are few significant differences between contralateral humeral anatomic characteristics. Therefore, the uninjured contralateral humerus can provide a reasonable approximation to the native geometry of the fractured humerus and should be a reliable model for measuring parameters related to implant geometry and optimal positioning during hemiarthroplasty for the treatment of proximal humeral fractures.