In children, acute osteomyelitis, an infection of the bone, is most commonly hematogeneous in origin. Osteomyelitis is most often diagnosed with magnetic resonance imaging (MRI) and findings may include marrow signal changes on T1 and T2, with abnormal enhancement after gadolinium. Imaging helps detect any associated intraosseous or subperiosteal abscesses, which may require orthopedic drainage. In this pictorial essay, we demonstrate the association of acute pediatric osteomyelitis with physeal separation, resulting in what may be confused for simple trauma, although there was no known history of trauma in any of the cases we researched. All of the cases had a large subperiosteal fluid collection with marked separation of the epiphysis from the metaphysis. It is important to recognize this potential association in osteomyelitis, as it is readily visible by radiographs and may lead to diagnostic uncertainty.