The medullary vascular syndromes revisited.

There are two major vascular syndromes of the medulla oblongata: the medial and the lateral. The medial medullary syndrome is characterized by the triad of ipsilateral hypoglossal nerve palsy with contralateral hemiparesis and loss of deep sensation. Lateral medullary infarction commonly presents with Horner's syndrome, ataxia, alternating thermoanalgesia, nystagmus, vertigo and hoarseness. Combinations of the two major syndromes occur as bilateral medial medullary, hemimedullary and bilateral lateral medullary syndromes. Each of these syndromes frequently manifests with incomplete or atypical findings depending on the extent of the lesion. Magnetic resonance imaging has been useful in the clinical diagnosis of medullary infarctions. The site of the lesion may help predict the arteries involved.