A 3-year-old is brought to the clinic complaining of a painful right elbow. He is holding the right arm slightly flexed and pronated and refuses to move it. The mother states that symptoms started right after his older brother had been swinging him around by his arms. This presentation supports a diagnosis of:
a. radial head subluxation.
b. femoral anteversion.
c. carpal tunnel syndrome.
d. Osgood-Schlatter disease.
e. osteomyelitis.