Overview Snapshot A 59-year-old male presents with sensory changes on the right side of his face, left side of his body, and dizziness. He also reports some trouble with swallowing, and his wife noticed that his voice sounds hoarse. Past medical history is significant for hypertension and type 2 diabetes mellitus. On physical examination, there is a right-sided Horner’s syndrome. Uvula is deviated towards the left. There is right-sided vocal cord paralysis and absence of elevation of the right palate during phonation. There is loss of pain sensation on the right-sided face and left-sided trunk and limbs. (Lateral medullary syndrome) Introduction Circle of Willis Artery Syndrome Presentation Anterior Spinal artery Medial medullary syndrome Ipsilateral paralysis of hypoglossal nerve Contralateral hemiparesis of the upper and lower extremity Medial lemniscus (↓ contralateral vibration and proprioception) Posterior inferior cerebellar artery (PICA) Lateral medullary syndrome Ipsilateral manifestations facial loss of pain and temperature ataxia (arm and leg, gait) hoarseness dysphagia Horner syndrome Contralateral manifestations pain and temperature hemisensory loss Nausea, nystagmus, vomiting, vertigo Anterior inferior cerebellar artery (AICA) Lateral pontine syndrome Ipsilateral manifestations facial paralysis loss of lacrimation reduced salivation loss of corneal reflex loss of sensation of the anterior 2/3rd of the tongue Horner syndrome sensorineural hearing loss loss of facial pain and temperature Contralateral manifestations pain and temperature hemisensory loss Posterior cerebral artery - Contralateral homonymous hemianopia with macular sparing Middle cerebral artery - Contralateral manifestations facial paralysis and sensory loss upper extremity weakness and sensory loss hemineglect (if stroke is in non-dominant hemisphere) aphasia (if stroke is in dominant hemisphere-Broca's area) Anterior cerebral artery - Contralateral manifestations lower extremity weakness and sensory loss Posterior communicating artery - Ipsilateral compression leading to CN III palsy down-and-out, mydriasis Lenticular striate artery - Contralateral manifestations motor hemiparesis hemisensory loss Lack of cortical signs no aphasia, neglect Basilar artery Locked-in syndrome Quadriplegia Preserved reticular formation Intact vertical eye movement Intact blinking Anterior communicating artery - Can compression of optic chiasm bitemporal hemianopia If rupture, ischemia in anterior cerebral artery territory