Abstract
We report a 59-year-old man with a brainstem infarction. He had previously suffered from cerebral infarction of the left frontal lobe, and it was pointed out at that time that his right anterior inferior cerebellar artery arose from the right vertebral artery. He was admitted to our hospital with dysarthria and left hemisensory disturbance. On arrival, he showed conjugate deviation of the eyes to the left, and after treatment he demonstrated internuclear ophthalmoplegia. His symptom suggested that the focus of brain infarction involved the right paramedian pontine reticular formation. Magnetic resonance angiography showed that the right vertebral artery occluded, and magnetic resonance imaging demonstrated a brain infarction in the posterior right middle upper medulla and inferior pons. It was suggested that the right pontine perforator arteries arose from the right vertebral artery, as his right anterior inferior cerebellar artery did. His eye movements after treatment were similar to those in left medial longitudinal fasciculus syndrome, although the focus of the infarction was demonstrated on the right pons. This was because the internuclear neuron, which connects the left oculomotor nucleus to the right abducens nucleus was injured between the right abducens nucleus and the left medial longitudinal fasciculus. Since the vertebrobasilar arteries showed a normal variant in which the right anterior inferior cerebellar artery arose from the vertebral artery, right vertebral artery occlusion led to pontine infarction and symptoms suggesting that the right pons was affected.
