Congenital odontoid aplasia and posterior circulation stroke in childhood

Head trauma and vigorous physical activity were followed by delayed‐onset posterior circulation stroke in a 5‐year‐old boy with odontoid aplasia and C1‐C2 subluxation. Angiography demonstrated vertebral artery narrowing and occlusion of the left anterior‐inferior cerebellar and posterior cerebral arteries. Odontoid aplasia and other atlantoaxial dislocations are treatable causes of posterior circulation insufficiency in childhood; these defects may be overlooked without appropriate radiographic study of the cervical spine using flexionextension views.