The epiphyseal fracture-separation of the distal humerus is extremely rare injury in neonates. It is frequently misdiagnosed as a elbow dislocation owing to the invisible cartilagenous portion of the distal humerus in roentgenograms. We described a case, 9-day-old neonate with finally diagnosed the Salter-Harris type 1 injury of the distal humeral epiphysis. He was referred for further evaluation of 'refusal to use the left arm' from a local clinic. The injury had initially misdiagnosed as normal roentgenograms by a local orthopedic specialist, so we preferentially give an impression of the brachial plexus injury or the hemiplegic cerebral palsy. But electromyography and brain magnetic resonance imaging were negative findings. A neonate was referred to the pediatric orthopedic subspecialist and properly diagnosed. He was treated with the closed reduction and the percutaneous pinning. No complication has occurred. (J Korean Acad Rehab Med 2006; 30: 409-412)
