The patient is a 6-years-5-month-old boy, who complained of difficulty in elevating his rightarm after practicing with a 3.5kg weighted drum when aged 6-years•3-month-old. Muscle weakness was evident in the deltoid and supraspinatus muscles. However, we found no limitation in nect range of motion. No remarkable results were seen in the following tests ; Jackson test (-), Spuring test (-), Wright test (-), Eden test (-), Moley test (+),Three minute stress test (-). On EMG examination, results

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... rted to improve 5 months after his initial complaint. We concluded that brachial plexus injury in this case was caused by compression and/or overtraction of the brachial plexus by the heavy weight of the drum and the band.