Trochlear nucleus

The nucleus of the trochlear nerve is located in the midbrain, at an intercollicular level between the superior colliculus and inferior colliculus.[1] It is a motor nucleus, and so is located near the midline, embedded within the medial longitudinal fasciculus (see diagram at right). The oculomotor nerve and trochlear nerve are the only two cranial nerves with nuclei in the midbrain, other than the trigeminal nerve, which has a midbrain nucleus called the mesencephalic nucleus of trigeminal nerve, which functions in preserving dentition.

Trochlear nucleus
Outline of the nucleus raphes dorsalis:
DRif interfascicular subnucleus,
DRv ventral subnucleus
DRvl ventrolateral subnucleus
DRd dorsal subnucleus
mlf medial longitudinal fasciculus
Aq cerebral aqueduct
IVn trochlear nucleus.
The cranial nerve nuclei schematically represented; dorsal view. Motor nuclei in red; sensory in blue. (Trochlear is "IV")
Details
Identifiers
Latinnucleus nervi trochlearis
NeuroNames513
NeuroLex IDbirnlex_1488
TAA14.1.06.319
FMA54518
Anatomical terms of neuroanatomy

Oddly, fibers from the trochlear nucleus cross over in the trochlear decussation of the midbrain, located in the superior medullary velum to exit dorsally, the only cranial nerve to do so. The trochlear nerve then goes around the midbrain, and is visible coming out of the sides.

See also

Additional images
  • Nuclei of origin of cranial motor nerves schematically represented; lateral view.
  • Scheme showing central connections of the optic nerves and optic tracts.
  • Brain stem sagittal section

References
  1. Baxter, Donald; Olsewski, Jerzy (1982). Cytoarchitecture of the Human Brain Stem (2nd ed.). Basel: S. Karger. pp. 50–51. ISBN 3-8055-2210-X.
  • Atlas image: n2a4p4 at the University of Michigan Health System - "Brainstem, Cranial Nerve Nuclei, Sagittal Section, Medial View"


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