Congenital Absence of the Posterior Arch of the Atlas

A 22-year-old woman was admitted to our emergency department after a traffic accident. She was hit by a car when she was riding a bike. She complained of pain at the front of her neck, but of no neurologic symptoms in the limbs. On examination, she had generalized tenderness over her cervical spine. Neurologic examination was unremarkable. Cervical computed tomography scan showed a bony defect of the posterior arch of atlas. No evidence of compression of the spinal cord was shown on magnetic resonance imaging (Fig. 1, Fig. 2). The patient was admitted for observation and treated with a cervical collar. Her symptoms decreased within 48 hours. She was asked to avoid contact sports and athletic activities. On the last follow-up after 12 months, she was asymptomatic and fully active. Fig. 2Sagittal T2-weighted magnetic resonance imaging revealing no compression of the spinal cord. View Large Image Figure Viewer Download Hi-res image