Internal capsule
547735
224604145
2008-07-09T16:49:41Z
79.71.62.155
/* Fibers */
{{Infobox Brain|
Name = {{PAGENAME}} |
Latin = capsula interna |
GraySubject = 189 |
GrayPage = 836 |
Image = Telencephalon-Horiconatal.jpg |
Caption = Horizontal section of right cerebral hemisphere. (Capsula interna labeled at upper left.) |
Image2 = Gray764.png |
Caption2 = The motor tract. |
IsPartOf = |
Components = |
Artery = |
Vein = |
BrainInfoType = hier |
BrainInfoNumber = 180 |
MeshName = |
MeshNumber = |
DorlandsPre = c_07 |
DorlandsSuf = 12211417 |
}}
The '''internal capsule''' is an area of [[white matter]] in the [[brain]] that separates the [[caudate nucleus]] and the [[thalamus]] from the [[lenticular nucleus]]. The internal capsule contains both ascending and descending axons.
It consists of [[axon]]al fibres that run between the [[cerebral cortex]] and the [[pyramids of the medulla]].
==Components==
The internal capsule is V-shaped when cut both ''coronally'' (on the same plane as the face) and ''horizontally''/''transversely'' (the same plane as the brim of a [[top hat]]).
When cut horizontally:
* the bend in the V is called the "[[Genu_of_the_internal_capsule|genu]]".
* the part in front of the genu is the "[[anterior limb]]". or ''crus anterius''.
* the part behind the genu is called the "[[posterior limb]]" or ''crus posterius''.
There is also a ''retrolenticular'' and a ''sublenticular'' part to the internal capsule.
==Fibres==
* The posterior limb of the internal capsule contains [[corticospinal fiber]]s and sensory fibers from the body.
* The genu contains [[corticobulbar fiber]]s, which run between the [[cerebral cortex|cortex]] and the [[brainstem]].
* The anterior limb of the internal capsule contains:
** 1) [[frontopontine]] (corticofugal) fibers project from [[frontal cortex]] to [[pons]];
** 2) [[thalamocortico fibers]] connect the [[Medial dorsal nucleus| medial]] and [[anterior thalamic nuclei|anterior]] nuclei of the thalamus to the [[frontal lobe]]s (these are severed during a [[prefrontal lobotomy]]).
* The retrolenticular part contains fibers from the optic system, coming from the [[lateral geniculate nucleus]] of the [[thalamus]]. More posteriorly, this becomes the [[optic radiation]]. Some fibers from the [[medial geniculate nucleus]] (which carry auditory information) also pass in the retrolenticular internal capsule, but most are in the sublenticular part.
==Blood supply==
Blood supply is similar to the other structures of the region. mainly [[Striate arteries]], which come off the [[middle cerebral artery]], enter through the [[anterior perforated substance]] in the base of the brain.
The capsular branch of [[posterior cerebral artery]] which is called the [[thalamogeniculate artery]] supplies the posterior limb of the capsule, while the anterior limb is supplied by striate arteries from the [[middle cerebral artery]] and Heubner's artery which is the capsular branch of [[anterior cerebral artery]].
==Pathology==
[[Infarction]]s to the internal capsule tend to be small, punctate [[lesion]]s.
They can affect sensory and motor systems on the opposite side of the body, and possibly [[eyesight]] (to the contralateral visual field).
[[Hearing (sense)|Hearing]] should not be affected in a single capsule lesion, as this information crosses over to both sides of the brain while in the brainstem.
==Additional images==
<gallery>
Image:Gray684.png|Deep dissection of brain-stem. Lateral view.
Image:Gray689.png|Superficial dissection of brain-stem. Ventral view.
Image:Gray717.png|Coronal section of brain immediately in front of pons.
Image:Gray718.png|Coronal section of brain through intermediate mass of third ventricle.
Image:Gray730.png|Section of brain showing upper surface of temporal lobe.
Image:Gray743.png|Coronal section through anterior cornua of lateral ventricles.
Image:Gray744.png|Coronal section of brain through anterior commissure.
Image:Gray745.png|Dissection showing the course of the cerebrospinal fibers.
Image:Gray746.png|Diagram of the tracts in the internal capsule.
Image:Human brain right dissected lateral view description.JPG|Human brain right dissected lateral view
</gallery>
==External links==
* {{BrainMaps|internal%20capsule|internal capsule}}
* {{BrainInfo|hier|180}}
* {{RocheLexicon|13048.000-2}}
{{Prosencephalon}}
[[Category:Central nervous system pathways]]
[[de:Capsula interna]]
[[it:Capsula interna]]
[[pt:Cápsula interna]]