An uncommon case mimicking cervical trauma: Os odontoideum.

Os odontoideum is a separate odontoid process from the body of the axis. It is the most common anomaly of the odontoid process. Patients with this condition can be asymptomatic or present with a wide range of neurological dysfunctions. It may cause cervical instability, atlantoaxial dislocation and myelopathy. This anomaly can mimic Type I and II odontoid fractures. There is a role for conservative treatment of an asymptomatic incidentally found, radiologically stable and non-compressive os odontoideum. However, surgical treatment has a definitive role in symptomatic cases. In this study, the case is presented of a 31 year-old male patient with neck pain who was diagnosed with incidental os odontoideum. The diagnosis of acute odontoid fracture was discarded in this case as the radiological findings were of a characteristic cortex with smooth contours, and there was no history of recent trauma, sclerosis or hypertrophy of the anterior tubercle of the atlas.