Occult Radial head fracture
History and Physical Exam
The patient will complain of proximal forearm or elbow pain. Tenderness to palpation will be on the lateral elbow and the patient will have variable degrees of difficulty in elbow range of motion depending on the size of the effusion. Pain will also be elicited on passive forearm pronation, which rotates the radial head. Document a thorough neurovascular exam, particularly of the anterior interosseous branch of the median nerve. This can be tested by asking the patient to make an "OK" sign with the thumb and index finger.