Acute os styloideum injury in an elite athlete.

The os styloideum, an accessory carpal bone, may suffer injury during traumatic wrist flexion. The case described corresponds to an acute os styloideum injury in an elite athlete; a diagnosis made using high-resolution computed tomography and magnetic resonance imaging permitted not only the identification of the anomaly and associated abnormalities but also ruled out more significant injury to the extensor carpi radialis brevis.