Abducens nucleus

Abducens nucleus
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Abducens_nucleus".

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Brain: Abducens nucleus

The cranial nerve nuclei schematically represented; dorsal view. Motor nuclei in red; sensory in blue. The olfactory and optic centers are not represented. (Abducens nucleus is VI)
Latin	nucleus nervi abducentis
Gray's	subject #187 787
Part of	Pons
Artery	Pontine branches of the Basilar artery
NeuroNames	hier-580
Dorlands/Elsevier	n_11/12581919

The abducens nucleus is the originating nucleus from which the abducens nerve emerges - a cranial nerve nucleus. This nucleus is located beneath the fourth ventricle in the caudal portion of the pons, medial to the sulcus limitans.

The abducens nucleus along with the internal genu of the facial nerve make up the facial colliculus, a hump at the caudal end of the medial eminence on the dorsal aspect of the pons.

Clinical significance

Damage to the abducens nucleus causes monocular medial ophthalmoparesis: specifically, loss of the ability to move the ipsilateral eye outward (abduction). This is also seen in damage of the abducens nerve.

In contrast, damage to the area of the nucleus can also result in lateral gaze paralysis: loss of the ability to move both eyes conjugately away from the side of the lesion. This is due to damage to both the motoneurons and interneurons projecting through the medial longitudinal fasciculus to the contralateral medial rectus neurons.

Additional images

Nuclei of origin of cranial motor nerves schematically represented; lateral view.	Scheme showing central connections of the optic nerves and optic tracts.	Figure showing the mode of innervation of the Recti medialis and lateralis of the eye.	Axial section of the Brainstem (Pons) at the level of the Facial Colliculus
Vestibulo-ocular reflex	Brain stem sagittal section

External links

v • d • e

Brain: rhombencephalon (hindbrain)

Metencephalon/
pons

Dorsal/ (tegmentum)	surface: Locus ceruleus Trigeminal lemniscus (Dorsal trigeminal tract, Ventral trigeminal tract) cranial nuclei: GSA: Principal V/Spinal V - VIII-c (Dorsal, Anterior)/VIII-v (Lateral, Superior, Medial, Inferior) - SVE: Motor V - VII - GSE: VI - GVE: VII: Superior salivary nucleus MLF, III, IV and VI (vestibulo-oculomotor fibers, medial vestibulospinal tract) sensory/ascending: Trapezoid body/VIII - Superior olivary nucleus Inferior cerebellar peduncle (Vestibulocerebellar tract) motor/descending: Apneustic center • Pneumotaxic center (Medial parabrachial nucleus) - Lateral parabrachial nucleus

Ventral/ (base)	Middle cerebellar peduncles (Pontocerebellar fibers) - Pontine nuclei motor/descending: Corticospinal tract - Corticobulbar tract - Corticopontine fibers

Raphe/reticular	Reticular formation (Caudal, Oral, Tegmental, Paramedian) • Raphe nuclei (Median)

Myelencephalon/
medulla

Dorsal	surface: Posterior median sulcus - Postero-lateral sulcus - Area postrema cranial nuclei: GVA: VII,IX,X: Solitary/tract • SVA: Gustatory nucleus • GSE: XII • GVE: IX,X,XI: Ambiguus • SVE: X: Dorsal • IX: Inferior salivatory nucleus - MLF, III, IV and VI sensory/ascending: Gracile nucleus • Cuneate nucleus (Accessory cuneate nucleus) • Sensory decussation • Medial lemniscus motor/descending: Dorsal respiratory group

Ventral	motor/descending: Ventral respiratory group - Pyramid (Motor decussation) - Inferior olivary nucleus (Olivocerebellar tract, Rubro-olivary tract) surface: Anterior median fissure - Antero-lateral sulcus - Arcuate nucleus of medulla - Olivary body

Raphe/reticular	Reticular formation (Gigantocellular, Parvocellular, Ventral, Lateral, Paramedian) • Raphe nuclei (Obscurus, Magnus, Pallidus)

v • d • e

Nerves of head and neck: the cranial nerves and nuclei

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

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