Acute annular ligament interposition into the radiocapitellar joint ("nursemaid's elbow") is a common injury in children younger than 5 years. The injury occurs when axial traction is applied to an extended, pronated arm. There are no abnormal radiographic findings associated with this condition. We recommend that children with a classic history and clinical presentation of an acute annular ligament interposition into the radiocapitellar joint be treated without obtaining radiographs.