Central Anatomy of the Fourth Nerve

Update item information
Identifier Midbrain_4th
Title Central Anatomy of the Fourth Nerve
Subject Figures; Mesencephalon OMS
Creator Daniel R. Gold, DO, Departments of Neurology, Ophthalmology, Neurosurgery, Otolaryngology - Head & Neck Surgery, Emergency Medicine, and Medicine, The Johns Hopkins School of Medicine
Description The IVth or trochlear nucleus is located ventral to the central periaqueductal grey matter, dorsal to the medial longitudinal fasciculus (MLF) and medial to the oculosympathetic tract at the level of the inferior colliculus. The fascicles of the IVth nerve travel dorsally and caudally around the central grey matter and decussate at the roof of the aqueduct, known as the anterior medullary velum. Thus, a IVth nerve palsy that is nuclear in origin is contralesional, while associated ipsilesional signs include: hemi-ataxia (superior cerebellar peduncle), Horner's syndrome (oculosympathetic tract), internuclear ophthalmoplegia (INO - due to MLF lesion), or an ipsilesional or contralesional relative afferent pupillary defect that occurs without a decrease in acuity, color vision or a visual field defect, due to a lesion involving the brachium of the superior colliculus. Upbeat nystagmus has also been described as occurring with a central IVth nerve palsy, presumably due to a lesion involving the superior cerebellar peduncle (brachium conjunctivum), through which the anterior semicircular canal fibers travel. Redrawn and modified with permission from Wolters Kluwer and the American Academy of Neurology originally published in Gold DR, Shin RK, Galetta SL. Pearls & Oysters: Central fourth nerve palsies. Neurology. 2012;79(23):e193-6.
Contributor Daniel R. Gold, D.O.
Publisher Spencer S. Eccles Health Sciences Library, University of Utah
Date 2017
Type Image/MovingImage
Format image/jpeg
Relation is Part of NOVEL: Neuro-ophthalmology Virtual Education Library Examination Collection
Rights Management Copyright 2017. For further information regarding the rights to this collection, please visit: https://NOVEL.utah.edu/about/copyright
Holding Institution Spencer S. Eccles Health Sciences Library, University of Utah, 10 N 1900 E, SLC, UT 84112-5890
Collection Neuro-ophthalmology Virtual Education Library: NOVEL http://NOVEL.utah.edu
Language eng
ARK ark:/87278/s6np5zcq
Setname ehsl_novel_gold
Date Created 2017-08-10
Date Modified 2021-05-06
ID 1260008
Reference URL https://collections.lib.utah.edu/ark:/87278/s6np5zcq
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