Infant with decreased motion of the right arm AP radiograph of the right humerus at presentation (left) is unremarkable. AP radiograph of the right humerus 1 month later (right) shows destruction and medial displacement of the epiphysis of the humerus and extensive periosteal reaction along the metaphysis and diaphysis of the humerus. The diagnosis was neonatal osteomyelitis due to Staphylococcus that crossed the growth plate.