Horner syndrome from the dentist's chair.

Horner syndrome results from a disruption of the sympathetic nervous system input to the eye and orbit. Many causes have been described, including thoracostomy tubes, carotid artery dissection, herpes zoster ophthalmicus, various headache syndromes, Pancoast tumor, head and neck surgery, and local trauma. In the medical literature, Horner syndrome has been reported as a sequela of prolonged positioning, twice as a result of general anesthesia, and once as a result of an alcoholinduced coma. We report a case of Horner syndrome in a conscious patient resulting from a visit to the dentist’s chair.