We conducted a study to assess the efficacy of the use of osteophony in the evaluation of shoulder trauma. Evaluation of the shoulder includes the physical examination and often a radiographic series. We studied the usefulness of the olecranon-manubrium percussion (OMP) test, a physical diagnostic procedure performed in shoulder trauma. The bell of the stethoscope is placed over the manubrium, both elbows are flexed at 90 degrees, and the olecranon is percussed. In the normal examination with no disruption of bony conduction, both sides should produce a crisp equal sound. In the event of a dislocation or fracture with disruption of bony conduction, the affected side should be duller in pitch and intensity. We evaluated the utilization of the OMP test to assess its accuracy when used as a screening test for radiographs in conjunction with the physical examination and radiographic examination. Ninety-six patients were prospectively evaluated by the OMP test and also received radiographs. In those patients who had radiographic abnormalities, 40 of 47 (85.1%) had an abnormal OMP sign. In those patients without radiographic abnormalities, none had an abnormal OMP sign. In assessing anterior shoulder dislocations, 11 of 13 (84.6%) had an abnormal OMP sign (P less than .02). After relocation, 100% had a normal OMP sign. Of those with clavicular fractures, nine of nine (100%) had abnormal OMP signs (P less than .005). Of those with a fracture of the humerus, 16 of 20 (80%) revealed an abnormal OMP test (P less than .01). The test was not significant in assessing acromio-clavicular joint abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)