Examiners use range-of-motion (ROM) testing to help calculate the physical examination modifier when they use the diagnosis-based impairment (DBI) method in the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides), Sixth Edition. DBI is the preferred method for calculating upper and lower extremity ratings, but, in instances specified by the regional grid, the evaluator may choose to use the ROM method, typically because it yields a higher impairment rating relative to the DBI method. In rare lower-limb cases when the injury is not fully articulated by the regional grid (eg, severe crushes, burns, and scarring), ROM may be used instead of diagnosis. In cases of amputation, ROM may be used for the remaining portion of the limb and combined with amputation rating as explained in sections of Chapter 15. Note that, in the AMA Guides, the extended anatomic position is 0° rather than 180°, and evaluators can consult the detailed diagrams of the planes of the thumbs, fingers, wrists, elbows, and shoulders. Invalid results are declared if, after three consecutive efforts, the three measurements for a given plane of motion vary more than 10° from the mean (average) of these three measurements. The article also discusses adjustments for functional history when the ROM method does not adequately capture the full impairment.