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
Latin	nucleus nervi trochlearis
MeSH	12582022
NeuroNames	hier-504
NeuroLex ID	Trochlear nucleus
TA	A14.1.06.319
FMA	54518
Anatomical terms of neuroanatomy []

The nucleus of the trochlear nerve is located in the lower midbrain, at the level of the inferior colliculus. It is a motor nucleus, so is located near the midline. The oculomotor nerve and trochlear nerve are the only two cranial nerves with nucleus in the midbrain.

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

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