Internal capsule

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The capsula interna (German: inner capsule ) is the largest collection of nerve fibers that ascend to the cerebral cortex or descend from the cerebral cortex.


Horizontal section through the forebrain, basal ganglia blue

Anatomically, the internal capsule is delimited on the inside by the thalamus and nucleus caudatus , on the outside by globus pallidus and putamen , together the controversial nucleus lentiformis . In the horizontal section, a crus anterius (anterior leg), a crus posterius (posterior leg) and the genu capsulae internae (knee) connecting the two legs can be seen. In the sagittal section three parts can be distinguished, the pars supralentiformis, retrolentiformis and sublentiformis. The internal capsule surrounds the Ncl. lentiformis from medial and above with the former part, behind with the middle and below with the latter part. Fibers mainly reach the occipital cortex ( visual tract) through the retrolentiform section of the inner capsule, while the sublentiform section leads to the occipital and temporal cortex (visual and auditory tract ).

The following important pathways run through the internal capsule and thus connect the cerebral cortex with underlying structures or the spinal cord :

Run in the crus anterius:

In genu:

  • Corticonuclear tract

Run in the crus posterius:

Blood supply

The crus anterius is supplied by the arteriae centrales anteromediales, coming from the arteria cerebri anterior , and by the arteria centralis longa. The genu is supplied by the arteriae centrales anterolaterales , the arteria cerebri media . The posterior crus is supplied by the anterior choroid artery , which arises directly from the internal carotid artery .


Damage in this area, for example in the context of a stroke ( medial infarction ), forming an internal capsule syndrome , can lead to, among other things, contralateral hemiparesis or diaphragmatic paralysis (see also: contralaterality of the forebrain ).


  • Martin Trepel: Neuroanatomy. 3. Edition. Urban and Fischer, Munich 2006, ISBN 3-437-44425-5 .

Web links

Individual evidence

  1. Heinz-Walter Delank: Neurology. 5th, revised and supplemented edition. Enke, Stuttgart 1988, ISBN 3-432-89915-7 , p. 75 f. ( Inner capsule syndrome ).