Review of Horner's syndrome and a case report.

Sympathetic denervation of the eye [Horner's Syndrome (HS)] usually presents as ptosis, miosis, and facial anhydrosis. HS presents a challenge to the clinician because the causative lesion may involve a first, second, or third-order neuron. This paper reviews the literature regarding HS, the anatomy of the sympathetic pathway to the eye, the diagnosis, and the localization of the lesion. Our patient developed reversible HS after a migrainous episode which presumably caused "bruising" of the sympathetic plexus within the carotid canal.