Contralateral trochlear nerve paresis and ipsilateral Horner's syndrome

John Guy, Arthur L. Day, J. Parker Mickle, Norman J. Schatz

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


Two patients had paresis of the trochlear nerve contralateral to the site of lesions in the brainstem. Both patients had ipsilateral blepharoptosis and miosis suggesting oculosympathetic paresis from involvement of the descending sympathetic tract, adjacent to the fourth cranial nerve nucleus and its fascicles, in the caudal mesencephalon. Cerebral angiography documented an arteriovenous malformation of the brainstem in Case 1. Magnetic resonance imaging disclosed a lesion of high signal intensity on T2-weighted images involving the dorsal mesencephalon in Case 2. Involvement of the superior cerebellar peduncle produced ipsilateral dysmetria and ataxia. Lesions involving the fourth cranial nerve nucleus or its fascicles, before decussation in the superior medullary velum, and adjacent sympathetic fibers may produce an ipsilateral Horner's syndrome and contralateral superior oblique muscle paresis.

Original languageEnglish (US)
Pages (from-to)73-76
Number of pages4
JournalAmerican journal of ophthalmology
Issue number1
StatePublished - Jan 15 1989
Externally publishedYes

ASJC Scopus subject areas

  • Ophthalmology


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