Introduction:

Posterior arch of the atlas congenital defects show an incidence of 0.7 to 3%. Most patients are usually asymptomatic, and the diagnosis is performed when X-rays are taken after cervical trauma.

Clinical report:

59 years old male, with a history of automobilistic accident five months ago, who goes to rehabilitation department with intermittent manifestations of amaurosis fugax, obtundation, rotating vertigo sensation with episodes lasting no more than 10 seconds related to neck movements, associated with cervicalgia and moderate occipital headache; on examination, normal gait, negative Romberg, normal cranial nerves, cervical spine with complete movements and absence of paravertebral muscle contractures. Simple radiographs were requested, which showed: posterior arch of the atlas absence, posterior tubercle persistence; lateral mass asymmetry, C4/C5 anterolisthesis, the cervical lordosis inverted, dynamic projections and tomography corroborated diagnosis, and the patient was referred to neurosurgery for spondylolisthesis management.

Conclusion:

Congenital anomalies of the atlas can be confused with Jefferson’s fracture in the emergency services.