Recurrent sixth nerve palsy associated with a hypoplastic Dorello's canal.

Recurrent sixth nerve palsies are usually idiopathic, although they have been postulated to be caused by a postinflammatory insult or abnormal cerebral circulation. We report the case a 9-month-old boy who had 2 episodes of a left abduction deficit that resolved spontaneously. A 3-dimensional high-resolution T2-weighted sequence magnetic resonance imaging scan of the head revealed a hypoplastic left 6th nerve and a small left Dorello's canal.