View source for Abducens nucleus

{{Infobox Brain|
  Name            = {{PAGENAME}} |
  Latin           = nucleus nervi abducentis |
  GraySubject     = 187 |
  GrayPage        = 787 |
  Image           = Gray696.png |
  Caption         = 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)|
  Image2          = |
  Caption2        = |
  IsPartOf        = [[Pons]]|
  Components      = |
  Artery          = Pontine branches of the [[Basilar artery]]|
  Vein            = |
  BrainInfoType   = hier |
  BrainInfoNumber = 580 |
  MeshName        = |
  MeshNumber      = |
  DorlandsPre     = n_11 |
  DorlandsSuf     = 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 [[Anatomical terms of location|caudal]] portion of the [[pons]], [[Anatomical terms of location|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 [[ophthalmoparesis|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 [[motoneuron]]s and [[interneuron]]s projecting through the [[medial longitudinal fasciculus]] to the contralateral [[medial rectus]] [[neuron]]s.

==Additional images==
<gallery>
 Image:Gray697.png|Nuclei of origin of cranial motor nerves schematically represented; lateral view.
 Image:Gray698.png|Primary terminal nuclei of the afferent (sensory) cranial nerves schematically represented; lateral view. 
 Image:Gray774.png|Scheme showing central connections of the optic nerves and optic tracts.
 Image:Gray785.png|Figure showing the mode of innervation of the Recti medialis and lateralis of the eye.
 Image:Brainstem Abducens.png|Axial section of the Brainstem (Pons) at the level of the Facial Colliculus
 Image:ThreeNeuronArc.png |[[Vestibulo-ocular reflex]]
</gallery>

==External links==
* {{BrainstemWisconsin|13VNAN}}
* {{LoyolaMedEd|Neuro/frames/nlBSs/nl27fr.htm}}
* [http://isc.temple.edu/neuroanatomy/lab/embryo_new/pons/2/ Template (look for "GSE")]
* {{BrainMaps|Abducens%20nucleus|Abducens nucleus}}

{{Rhombencephalon}}

[[Category:Brainstem]]
[[Category:Cranial nerves]]

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