A 32-year-old woman complained of swallowing difficulty after a general seizure. Neurological examination revealed unilateral palsies of the 9th, 10th, and 12th cranial nerves. CT, MRI and internal carotid artery angiogram were normal. Selective catheterization of the external carotid artery and ascending pharyngeal system suggested a cranial nerve ischaemic arterial syndrome. The apparent sparing of the eleventh nerve may be explained by the double vascularization of this nerve. This may also be related to the double innervation of the trapezius and sterno-cleido-mastoid muscles by the 11th nerve and cervical spinal nerves.