Synonym: Avellis syndrome
Neurological disorder characterized by a peculiar form of alternating paralysis. There is paralysis of the soft palate and vocal cords on one side and loss of pain sensation and temperature sense on the other side, including the extremities, trunk, and neck.
Horner's syndrome may be associated. In the original description, the vagus and glossopharyngeal nerves were involved; concomitant involvement of the neighbouring cranial nerves was observed late.
It usually results from occlusion (most often due to infarct or neoplasm) of the vertebral artery in lesions of the nucleus ambiguous and pyramidal tract.