Encyclopedia of Clinical Neuropsychology

2018 Edition
| Editors: Jeffrey S. Kreutzer, John DeLuca, Bruce Caplan

Trochlear Nerve

  • Ronald A. CohenEmail author
Reference work entry
DOI: https://doi.org/10.1007/978-3-319-57111-9_1408


The trochlear nerve (cranial nerve IV) innervates the superior oblique muscle in the superior orbital fissure. It plays a primary role in oculomotor control. It depresses and intorts the eye, pulling it laterally. The trochlear nerve acts in conjunction with the oculomotor nerve to enable eye movement in all directions.

Current Knowledge

The nucleus of the trochlear nerve is located in the caudal midbrain below aqueduct and the nucleus of the oculomotor nerve. The axon of the trochlear nerve runs dorsally and crosses the midline before it leaves the brainstem, so that lesions of the nucleus affect the contralateral eye. This contrasts with all other cranial nuclei lesions, which affect the ipsilateral side. It is necessary for normal saccadic eye movement, as well as visual search. It is the common efferent pathway for brain systems that control eye movement and provides for the necessary muscular response. The trochlear nerve receives input from subcortical systems mediated...

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References and Readings

  1. Carpenter, M. B. (1991). Core text of neuroanatomy (4th ed.). Baltimore: Williams & Wilkins.Google Scholar
  2. Kandel, E. R., Schwartz, J. H., & Jessell, T. M. (2000). Principles of neural science (4th ed.). New York: McGraw-Hill.Google Scholar
  3. Wilson-Pauwels, L., Akesson, E. J., & Stewart, P. A. (1998). Cranial nerves: Anatomy and clinical comments. Philadelphia: Marcel Decker.Google Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Clinical and Health PsychologyCollege of Public Health and Health Professions, University of FloridaGainesvilleUSA
  2. 2.Center for Cognitive Aging and MemoryMcKnight Brain Institute, University of FloridaGainesvilleUSA