Agenesis of internal carotid artery presenting with oculomotor nerve palsy after minor head injury.

We report a patient with unilateral agenesis of the internal carotid artery in whom the oculomotor nerve was paralyzed on the same side as the agenesis after a minor head injury. It is conceivable that the palsy was caused by sudden tension of the nerve between the petroclinoid ligament and the enlarged posterior communicating artery.