Shoulder motion description: The ISB and Globe methods are identical

Background Three-dimensional shoulder position may be described by rotation sequences such as the proposed ISB standard. Alternative techniques to describe position (the Globe method) seek to simplify this description by eliminating rotation sequences and substituting unambiguous measurements. Methods Both methods (ISB and Globe) were applied to an analysis of shoulder positions, and an overall comparison was performed. Findings The ISB and Globe methods are numerically identical and interchangeable. Interpretation While all analytic methods are mathematically equivalent, investigators have sought simpler and more easily-applied ways of describing shoulder position that would be accurate, easily understood by clinicians, and unambiguous. This study demonstrates that the ISB rotation sequence and Globe descriptive method are numerically the same.