Horner's syndrome

n.

A syndrome caused by a lesion in the sympathetic nervous system, especially the cervical chain or central pathways, and characterized by drooping upper eyelid, pupillary contraction, absence of sweating, and receding eyeball.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.