[A case of brainstem and cerebellar infarctions related to basilar impression].

We report a 30-year-old man presenting with medial longitudinal fasciculus (MLF) syndrome after an afternoon nap. Magnetic resonance imaging revealed a right medial pontine tegmental infarction and right cerebellar infarctions. This patient was complicated with basilar impression detected on cervical X-ray and MRI. Three-dimensional CT angiography disclosed that the odontoid process migrated into the posterior fossa, thrusting the bilateral vertebral arteries postero-laterally. The mechanical stress on the bilateral vertebral arteries may have caused infarctions in the territories of the posterior circulation of this patient with basilar impression.