Brain: Trochlear nucleus
Outline of the nucleus raphe 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")
Latin	nucleus nervi trochlearis
Gray's	subject #188 807
NeuroNames	hier-504
MeSH	n_11
NeuroLex ID	birnlex_1488

The nucleus of the trochlear nerve is located in the midbrain, at the level of the inferior colliculus. It is a motor nucleus, so located near the midline.

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 nerve then goes around the midbrain, and is visible coming out the sides.

[edit] See also

• trochlear nerve

[edit] 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

[edit] External links

• Atlas of anatomy at UMich n2a4p4 - "Brainstem, Cranial Nerve Nuclei, Sagittal Section, Medial View"
• nucleus+of+trochlear+nerve at eMedicine Dictionary

v • d • e Human brain: mesencephalon (midbrain) (TA A14.1.06, GA 9.800) Tectum (Dorsal) Surface Corpora quadrigemina: Inferior colliculi (Brachium of inferior colliculus), Superior colliculi (Brachium of superior colliculus) Grey matter Pretectal area White: Sensory/ascending Spinotectal tract · Central tegmental tract White: Motor/descending Tectospinal tract Peduncle (Ventral) Peduncle tegmentum White: Sensory/ascending lemnisci (Medial, Lateral) · Ascending MLF (Vestibulo-oculomotor fibers) · Spinothalamic tract · Anterior trigeminothalamic tract · Dentatothalamic tract White: Motor/descending Rubrospinal tract · Rubro-olivary tract · Descending MLF Grey: cranial nuclei GSA (V: Mesencephalic) - GSE (III: Oculomotor, IV: Trochlear) - GVE (III: Edinger-Westphal) Grey: other Periaqueductal gray/Raphe nuclei (Dorsal raphe nucleus) Ventral tegmental area • Pedunculopontine nucleus • Red nucleus riMLF Ventricular system Cerebral aqueduct Peduncle base White: Motor/descending Cerebral crus: Corticospinal tract · Corticobulbar tract · Corticopontine tract/Frontopontine fibers/Temporopontine fibers Grey: Substantia nigra Pars compacta · Pars reticulata Surface Superior cerebellar peduncle (Decussation of superior cerebellar peduncles) · Interpeduncular fossa

v • d • e Nerves of head and neck: the cranial nerves and nuclei (TA A14.2.01, GA 9.855) olfactory (AON->I) olfactory bulb · olfactory tract optic (LGN->II) optic chiasm · optic tract oculomotor (ON, EWN->III) superior branch (parasympathetic root of ciliary ganglion/ciliary ganglion) · inferior branch trochlear (TN->IV) no significant branches trigeminal (PSN,TSN,MN,TMN->V) trigeminal ganglion • ophthalmic • maxillary • mandibular abducens (AN->VI) no significant branches facial (FMN,SN,SSN->VII) near origin nervus intermedius • geniculate inside facial canal greater petrosal (pterygopalatine ganglion) · nerve to the stapedius · chorda tympani (lingual nerve, submandibular ganglion) at stylomastoid foramen posterior auricular · suprahyoid (digastric, stylohyoid) · parotid plexus (temporal, zygomatic, buccal, mandibular, cervical) vestibulocochlear (VN, CN->VIII) cochlear (striae medullares, lateral lemniscus) • vestibular (Scarpa's ganglion) glossopharyngeal (NA, ISN, SN->IX) before jugular fossa ganglia (superior, inferior) after jugular fossa tympanic (tympanic plexus, lesser petrosal, otic ganglion) • stylopharyngeal branch • pharyngeal branches • tonsillar branches • lingual branches • carotid sinus vagus (NA, DNVN, SN->X) before jugular fossa ganglia (superior, inferior) after jugular fossa meningeal branch · auricular branch neck pharyngeal branch (pharyngeal plexus) · superior laryngeal (external, internal) · recurrent laryngeal (inferior) · superior cervical cardiac thorax inferior cardiac · pulmonary · vagal trunks (anterior, posterior) abdomen celiac · renal · hepatic · anterior gastric · posterior gastric accessory (NA,SAN->XI) cranial · spinal hypoglossal (HN->XII) lingual branches