Marked by lesions of nucleus ambiguus, restiform body, and descending sympathetic tracts; also with hemiplegia and loss of proprioception and tactile sense on contralateral side. Condition is due to occlusion of vertebral artery below origin of posterior inferior cerebellar artery; results in paralysis of soft palate, pharynx, and larynx, as well as Horner syndrome on ipsilateral side.