Trochlear nucleus

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
TA98A14.1.06.319
TA25890
FMA54518
Anatomical terms of neuroanatomy

The trochlear nucleus (/ˈtrɒklɪər/)[1] is the motor nucleus of the trochlear nerve (cranial nerve IV). It is located in the medial midbrain.[2]

Structure

The trochlear nucleus is located in the midbrain, at an intercollicular level between the superior colliculus and inferior colliculus.[3] As with all motor nuclei of cranial nerves, it is located near the midline (i.e. in the medial midbrain).[2] It is embedded within the medial longitudinal fasciculus. It is situated immediately below the nucleus of the oculomotor nerve (CN III) (the only other cranial nerve with a nucleus in the midbrain besides the mesencephalic nucleus of trigeminal nerve, which functions in preserving dentition).

The trochlear nucleus is unique in that its axons run dorsally and cross the midline at the trochlear decussation (located in the superior medullary velum) in the midbrain before emerging from the brainstem posteriorly/dorsally.[citation needed] In other words, trochlear nucleus on one side gives rise to the trochlear nerve on the contralateral side. A lesion of the trochlear nucleus thus affects the contralateral eye, whereas lesions of all other cranial nuclei affect the ipsilateral side.[2]

Blood supply

The midbrain receives its arterial blood supply from the posterior cerebral artery, superior cerebellar artery, and basilar artery; disruption of blood flow through any of these vessels may disrupt blood supply to the trochlear nucleus.[2]

Additional images

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

References

  1. ^ "Trochlear | Definition of Trochlear by Oxford Dictionary on Lexico.com also meaning of Trochlear". Lexico Dictionaries | English. Archived from the original on November 12, 2020.
  2. ^ a b c d Kim, Seung Y.; Motlagh, Mahsaw; Naqvi, Imama A. (2022), "Neuroanatomy, Cranial Nerve 4 (Trochlear)", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 30725929, retrieved 2023-01-03
  3. ^ 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"


Stub icon

This neuroanatomy article is a stub. You can help Wikipedia by expanding it.