INTERNAL CAPSULE

INTERNAL CAPSULE
- Compact bundle of projection fibres
  - between thalamus and
    - caudate nucleus medially
    - lentiform nucleus laterally
  - these fibers
    - fan out rostrally
      - to form corona radiata
    - condense caudally
      - continue as crus cerebri
    - types
      - ascending ( corticopetal / sensory )
      - descending ( corticofugal / motor )
- Blood supply
  - middle cerebral artery
  - anterior cerebral artery
    - striate branches
    - recurrent artery of heubner
- shape
  - V shaped compact structure
    - concavity directed laterally
  - parts
    - Anterior limb
      - lies between
        
        head of caudate nucleus medially
        
        anterior part of lentiform nucleus
    - posterior limb
      - lies between thalamus medially and posterior part of lentiform nucleus
    - genu
      - bend between anterior and posterior limb
    - retro-lentiform part
      - lies behind lentiform nucleus
    - sublentiform part
      - lies below lentiform nucleus
  - Constituent fibers
    - Motor fibers ( corticofugal fibres )
      - corticopontine fibres
        
        largest single group of projection fibers
        
        naming ( named according to lobe from which they arise )
        
        frontopontine
        
        numerous
        
        pass through anterior limb , genu and posterior limb
        
        parietopontine
        
        pass through retrolentiform part
        
        occipitopontine
        
        pass through retrolentiform part
        
        temporopontine
        
        pass through sublentiform part
        
        relay in ipsilateral pontine nuclei
        
        from ipsilateral pons to contralateral cerebellum
      - pyramidal fibers
        
        corticonuclear
        
        corticospinal
      - extrapyramidal fibers
        
        corticorubral
        
        corticostriate
        
        corticonigral
  - corticopetal fibres ( sensory fibers )
    - thalamocortical fibres ( thalamic radiation )
      - according to direction
        
        anterior thalamic radiation
        
        connects
        
        anterior and dorsomedial nuclei of thalamus to frontal lobe
        
        passes through
        
        anterior limb
        
        superior thalamic radiation
        
        connects
        
        ventral tier of thalamic nuclei with sensory cortex of frontal and parietal lobes
        
        through
        
        anterior limb of internal capsule
        
        posterior thalamic radiation
        
        pass through
        
        retrolentiform part
        
        connects
        
        lateral geniculate body to primary visual cortex forming optic radiation
        
        inferior thalamic radiation
        
        pass through
        
        sublentiform part
        
        connects
        
        medial geniculate body with the primary auditory area of temporal lobe
        
        auditory radiation

1273	Capsula interna	Internal capsule
1274	Pontes grisei caudatolenticulares	Caudolenticular grey bridges; transcapsular grey bridges
1275	Crus anterius	Anterior limb
1276	Radiatio thalami anterior	Anterior thalamic radiation
1277	Tractus frontopontinus	Frontopontine fibres
1278	Genu capsulae internae	Genu of internal capsule
1279	Fibrae corticonucleares	Corticonuclear fibres
1280	Crus posterius	Posterior limb
1281	Radiatio thalami centralis	Central thalamic radiation
1282	Fibrae corticoreticulares	Corticoreticular fibres
1283	Fibrae corticorubrales	Corticorubral fibres
1284	Fibrae corticospinales	Corticospinal fibres
1285	Fibrae corticothalamicae	Corticothalamic fibres
1286	Fibrae parietopontinae	Parietopontine fibres
1287	Fibrae thalamoparietales	Thalamoparietal fibres
1288	Pars retrolentiformis	Retrolentiform limb; retrolenticular limb
1289	Fibrae occipitopontinae	Occipitopontine fibres
1290	Fibrae occipitotectales	Occipitotectal fibres
1291	Radiatio optica; fibrae geniculocalcarinae	Optic radiation; geniculocalcarine fibres
1292	Radiatio thalamica posterior	Posterior thalamic radiation
1293	Pars sublentiformis	Sublentiform limb; sublenticular limb
1294	Radiatio acustica; fibrae geniculotemporales	Acoustic radiation; geniculotemporal fibres
1295	Fibrae corticotectales	Corticotectal fibres
1296	Radiatio optica Gratiolet	Optic radiation Gratiolet
1297	Fibrae temporopontinae	Temporopontine fibres
1298	Fibrae corticothalamicae	Corticothalamic fibres
1299	Corona radiata	Corona radiata
1300	Capsula externa	External capsule
1301	Capsula extrema	Extreme capsule
1302	Commissura anterior	Anterior commissure
1303	Pars anterior	Anterior part
1304	Pars posterior	Posterior part