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Internal Capsule.pdf
- 2. OOi 1 n1ssur r ~OnQih..!1c:lll i~J ~asd · I.JS • Projection fibres- Internal capsule
- 3. nucleus Thalamus 10.24 Horizontal sec11u11 01 lilt cerebral hemisphere st10win9 the - nl lhti rnla o-n~I r~n-e-11l it Rostrum ol co,pi.c:; c.allosum /---~.__~---- :r~~l Ooc1pr1~• p<Jlt!' capS,Jle Pos1enu11111-0 of 1mema1 capsule Actf'CNeflocular part of internal capsule DEFINITION • Projection fibres (white matter) between • caudate nucleus and thalamus medially • lentiform nucleus laterally
- 4. • Internal Capsule- A compact bundle of fibres through which the large collections of fibres pass, including- • Thalamocortical fibres • Corticothalamic fibres • Corticopontine fibres • Corticobulbar fibres • Corticospinal fibres
- 5. • The fibres project from the cerebral cortex to the various nuclei of the extrapyramidal system (e.g., the putamen and caudate nucleus). • It is a continuous sheet of fibres that forms the medial boundary of the lenticular nucleus. • It continues around posteriorly and inferiorly to partially envelop this nucleus. • Inferiorly, many of the fibres of the internal capsule funnel into the cerebral peduncles.
- 6. • Superiorly, the fibres fan out into the corona radiata. • Here, they travel in the cerebral white matter to reach their cortical origins or destinations. The internal capsule is divided into 5 regions: • The anterior limb is the portion between the lenticular nucleus and the head of the caudate nucleus; • The posterior limb is the portion between the lenticular nucleus and the thalamus; • The genu is the portion at the junction of the above 2 parts and is adjacent to the interventricular foramen; • The retrolenticular part is the portion posterior to the lenticular nucleus; • The sublenticular part is the portion inferior to the lenticular nucleus.
- 7. Portion Description Origin Destination Anterior Limb Anterior thalamic radiation • Anterior nucleus • DM • Cingulate gyrus • Prefrontal cortex Genu Relays to motor areas VA VL Premotor cortex Primary motor cortex Posterior Limb 1. Motor pathways: o Corticospinal tract o Corticobulbar tract 2. Somatosensory relays 1. Motor cortex 2. VPL/VPM 1. Motor pathways: o Spinal cord o Brainstem 2. Somatosensory relays: o Primary somatosentory cortex Retrolenticular Association relay Optic radiation • Pulvinar • LGN Association cortex Visual cortex Sublenticular Optic radiation Auditory radiation LGN MGN Visual cortex Auditory cortex
- 8. Portion Descending fibres Ascending fibres Radiations Anterior Limb •Frontopontine •Frontothalamic Thalamofrontal Anterior thalamic radiation Genu •Frontopontine •Corticonuclear Fibres carrying somaesthetic sensations from thalamus (VP nu.) to postcentral gyrus Superior or Dorsal thalamic radiation Posterior Limb •Frontopontine •Corticospinal •Corticorubral •Corticoreticular •Parietothalamic •Thalamoparietal fibres •Subthalamic fasciculus Retrolenticular •Parietopontine •Occipitopontine •Corticorubral •Occipitothalamic •Optic radiation •Thalamo-occipital •Thalamo-parietal Posterior or Caudal thalamic radiation Sublenticular •Parietopontine •Temporopontine •Temporothalamic •Acoustic radiation •Thalamotemporal Inferior thalamic radiation
- 9. CAUDATE NUCLEUS LENTIFORM NUCLEUS THALAMUS Globus palidus Putamen CLAUSTRUM Internal capsule External capsule Extreme capsule
- 10. Neural cortex Lateral White ventricles matter .nuclei ventricle Cerebral D. ie. ncephalon Third Septum pelluciidum
- 11. . ',·. _. ·:"-_·-:f-1=~ ·. -.-! :::,, . . -. .. .. . .. . . - . - ~ ..... · ~ L:::::l L--1_ __JI / Caudate nucleus Parts of internal capsule Anterior limb Genu Thalamus Thalamocortical fibres Corticopontine fibres Corticonuclear & corticospinal fibres Lentiform nucleus Posterior limb Sublentiform Retrolentiform
- 12. i irtal fissure Types of fibres • Thalamic radiation – Superior thalamic radiation – Anterior thalamic radiation – Posterior thalamic radiation- – Inferior thalamic radiation- • Corticospinal • Corticonuclear • Corticopontine – Fronto pontine – Parieto pontine – Temporo pontine • Extrapyramidal Superior Inferior Anterior Posterior
- 13. Thalamic radiation • Thalamocortical fibres – Thalamic nuclei -project to ipsilateral cerebral cortex (except for reticular nucleus) • Reach neocortex • Located entirely within internal capsule • Superior-from ventral nucleus – Becomes corona radiata • Anterior-from anterior & medial nuclei • Posterior-from optic radiation • Inferior-from auditory radiation
- 14. .................. .................. ................... ................... ................... ................... ................... .................... .................... .................... .................... .................... ..................... ..................... ..................... ..................... ..................... ...................... ...................... ...................... ...................... ........................ ......................... ......................... .......................... .......................... ......................... ANTERIOR LIMB – RETROLENTIFORM •Anterior thalamic radiation • Post thalamic •Frontopontine radiation - Optic radiation GENU • Parieto-pontine •Part of superior thalamic • Temporo-pontine radiation •Frontopontine SUBLENTIFORM •Corticonuclear • Inf thalamic radiation - Auditory POSTERIOR LIMB •Superior thalamic radiation •Frontopontine •Corticonuclear (corticobulbar) •Corticospinal •Extrapyrimidal Thalamocortical fibres Corticopontine fibres Corticonuclear & – radiation corticospinal fibres
- 15. nucleus Thalamus 10.24 Horizontal sec11u11 01 Int:: ce1 ·eoral hemisphere sflowin9 the " n l l h ti r.....~..~, ...~ n1-e-11l it Rostrum ol cOJpus cauosum - --------,,---~~=-..,...---- ::~ Ooc::1 pr1 ~•poae capS>Jle Pos1t:ir:iu1 1 1 11'° of 1mema1 capsule Aetrolenocular part of internal capsule BLOOD SUPPLY • Lateral striate fr middle HORIZONTAL SECTION cerebral artery – Ant limb – Genu – Post limb – Basal ganglia • Medial striate fr anterior cerebral artery – Ant limb – Genu – Basal ganglia • Ant choroidal fr internal carotid – Post limb – Retrolenticular part
- 16. ies orBrain Corpus ·stria!tum (caudate .and !Mtiform nucleij ln:;;ul1 1 (is!.and of Reil) PireceMral fpe~ Ro1andic=) and cen~r-al (Rolandic:) suloal and p.a:rietal art@ries Tempi.u~lbrinchi;is o1 . · 1 m"ddf(- cerebi· al ane. ry •most common!~ arf<s'.e,s: d~al to anterlor- c:ommunlcatl.on arter, c~Uoso:mirgin~ ~ne,ies ·(branches., of ante1icr o@r@b·ii if,t@ri@,s) .- ericallos'3J .arteries (branci'.es o f:an~im oerebr.al ~teries} T,unk of c01pus corpus c~~m CORONAL SECTION Lenticulostriate arteries Internal capsule Middle cerebral artery Internal carotid artery Anterior cerebral artery Medialstriate arteries
- 18. ANTERIOR LIMB • Ant cerebral artery through medial striate br. • Middle cerebral artery through lateral striate and lenticulostriate br. - pass through the lentiform N to supply the striate
- 19. GENU • Ant cerebral artery through medial striate br. • Middle cerebral artery through lateral striate and lenticulostriate br. • Branches of internal carotid artery
- 20. ies orBrain Corpus ·stria!tum (caudate .and !Mtiform nucleij ln:;;ul1 1 (is!.and of Reil) PireceMral fpe~ Ro1andic=) and cen~r-al (Rolandic:) suloal and p.a:rietal art@ries Tempi.u~lbrinchi;is o1 . · 1 m"ddf(- cerebi· al ane. ry •most common!~ arf<s'.e,s: d~al to anterlor- c:ommunlcatl.on arter, c~Uoso:mirgin~ ~ne,ies ·(branches., of ante1icr o@r@b·ii if,t@ri@,s) .- ericallos'3J .arteries (branci'.es o f:an~im oerebr.al ~teries} T,unk of c01pus corpus c~~m CORONAL SECTION Lenticulostriate arteries Internal capsule Middle cerebral artery Internal carotid artery Anterior cerebral artery Medialstriate arteries
- 21. POSTERIOR LIMB • Middle cerebral artery through lateral striate and lenticulostriate br. – Charcot’s artery of cerebral haemorrhage • Anterior choroidal artery, direct branch of internal carotid artery – Long and slender, thus has tendency to get thrombosis
- 22. CAUDATE NUCLEUS LENTIFORM NUCLEUS THALAMUS Globus palidus Putamen CLAUSTRUM INTERNAL CAPSULE
- 23. CAUDATE NUCLEUS LENTIFORM NUCLEUS THALAMUS Globus palidus Putamen CLAUSTRUM EXTERNAL CAPSULE Projection fibres from cerebral cortex to basal ganglia and midbrain
- 24. APPLIED ANATOMY – Microaneurysm to lenticulostriate arteries - • contralateral side of the body – – Hemiplegia – Impaired sensation – Paralysis of lower half of face – Thrombosis – recurrent br of ACA • contralateral side of the body – – Upper limb – Paralysis of lower half of face – Anterior choroidal artery • may be symptomless – collateral circulation