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.

[edit] 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.

[edit] Additional images

Nuclei of origin of cranial motor nerves schematically represented; lateral view.	Primary terminal nuclei of the afferent (sensory) cranial 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

[edit] External links

v • d • e Brain: rhombencephalon (hindbrain)
Myelencephalon/medulla	Arcuate nucleus of medulla, Solitary nucleus, Hypoglossal nucleus, Nucleus ambiguus, Olivary body, Inferior olivary nucleus, Cuneate nucleus, Accessory cuneate nucleus, Gracile nucleus, Inferior salivatory nucleus, Raphe nuclei (Obscurus, Magnus, Pallidus), Area postrema, Posterior nucleus of vagus nerve, Reticular formation (Gigantocellular nucleus, Parvocellular reticular nucleus, Ventral reticular nucleus, Lateral reticular nucleus, Paramedian reticular nucleus), Pyramid (Decussation)
Metencephalon/cerebellum	Vermis, Flocculus, Arbor vitae
Metencephalon/pons	Pontine tegmentum, Superior salivary nucleus, Trapezoid body, Pontine nuclei (Superior olivary nucleus, Trigeminal nerve nuclei, Abducens nucleus, Facial motor nucleus, Cochlear nuclei, Vestibular nuclei), Locus ceruleus, Paramedian pontine reticular formation, Median raphe nucleus - Reticular formation (Caudal pontine reticular nucleus, Oral pontine reticular nucleus, Tegmental pontine reticular nucleus)
Fourth ventricle	Obex, Median aperture