Educational objective: Lateral medullary infarct (Wallenberg syndrome) occurs due to occlusion of the posterior inferior cerebellar or vertebral artery. Patients develop loss of pain and temperature over the ipsilateral face and contralateral body, ipsilateral bulbar muscle weakness, vestibulocerebellar impairment (eg, vertigo, nystagmus), and Horner's syndrome. Motor function of the face and body is typically spared.
