What causes Horner syndrome?

Updated: May 01, 2019
  • Author: Christopher M Bardorf, MD, MS; Chief Editor: Edsel Ing, MD, MPH, FRCSC  more...
  • Print


Horner syndrome can be congenital, acquired, or purely hereditary (autosomal dominant). The interruption of the sympathetic fibers may occur centrally (ie, between the hypothalamus and the fibers’ point of exit from the spinal cord [C8 to T2]) or peripherally (ie, in cervical sympathetic chain, at the superior cervical ganglion, or along the carotid artery). [6]

The common lesions that cause Horner syndrome interfere with preganglionic fibers as they course through the upper thorax. Virtually all lesions producing postganglionic sympathetic dysfunction are located intracranially or intraorbitally because the superior cervical ganglion is near the skull. Preganglionic Horner syndrome indicates a serious underlying pathology and is associated with a high incidence of malignancy. Postganglionic involvement has primarily benign causes (ie, usually a vascular headache).

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!