The Cerebellum
Position
Lies above and behind the medulla and pons and occupies posterior cranial fossa
Its surface is high convoluted, forming folds or folia, being oriented transversely
Cerebellum
External features
Consists of two cerebellar hemisphere united in the midline by the vermis
External features
Three peduncles Inferior cerebellar
peduncle - connect with medulla and with spinal cord, contain both afferent and efferent fibers
Middle cerebellar peduncle - connect with pons, contain afferent fibers
Superior cerebellar peduncle - connect with midbrain, contain mostly efferent fibers
External features
Tonsil of cerebellum two elevated masses on inferior surface of hemispheral portion just nearby foramen magnum
Lobes
Two deep fissures
Primary fissure
Uvulonodular fissure
Three lobs
Flocculonodular lobe
Anterior
Posterior lobe
Lobes
Primary fissure
Posterolateral fissureFlocculonodular lobe
Anterior lobe
Posterior lobe
corpus of cerebellar
Internal structures Gray matter Cerebellar cortex Cerebellar nuclei
Dentate nucleus Fastigial nucleus Emboliform nucleus Globose nucleus
White matter
Internal structures
Cerebellar cortex
Dentate nucleus
Fastigial nucleus
Globose nucleus
Emboliform nucleus
medullary center
1. fastigial 1. fastigial
nucleusnucleus
2. globose 2. globose
nucleusnucleus
3. emboliform 3. emboliform
nucleusnucleus
4. dentate 4. dentate
nucleusnucleus
Deep NucleiDeep Nuclei
Three functional divisions Vestibulocerebellum
Archicerebellum Flocculonodular lobe
Spinocerebellum Paleocerebellum Vermis and intermediate
zone Cerebrocerebellum
Neocerebellum Lateral zone
Flocculonodular lobe
Verm
is In
termed
iate zo
ne
Lateral
zon
e
IVth vent VermisIntermediate hem.
Spinocerebellum: Vermis Intermediate hem.Spinocerebellum
(Vermis + Intermed. Hem)
Control of limbs and trunk
Lateral hem.
Cerebrocerebellum: Lateral hem.
Cerebrocerebellum(Lateral hemisphere)
Planning of movement+
Floculo-nodular lobe
Vestibulo-cerebellum(Floculo-nodular lobe)
Control of eye & head movementsBalance
Cerebellar divisions
Connections and function of cerebellum
Vestibulocerebellum Connections
Afferents: receive input from vestibular nuclei and inner ear.
Efferents: projects to the vestibular nucleus → vestibulospinal → motor neurons of anterior horn
Function: involved in eye movements and maintain balance
Connections and function of cerebellum
Spinocerebellum Connnection
Afferents: receive somatic sensory information via spinocerebellar tracts
Efferents: Fastigeal reticular and fastigial vestibular pathways:
Vermis projects to the fastigial nucleus → vestibular nuclei and reticular formation → vestibulospinal tract and reticulospinal tract → motor neurons of anterior horn
Intermediate zone projects to the interposed nuclei Globose- emboliform-rubral pathway: Contralateral red nucleus →
rubrospinal tract →motor neurons of anterior horn
Function: play an important role in control of muscle tone and coordination of muscle movement on the same side of the body
Connections and function of cerebellum
Cerebrocerebellum Connection
Afferents: receives input from the cerebral cortex via a relay in pontine nuclei(corticopontocerebellar pathway)
Efferents: (dentothalamic pathway):
dentate nucleus → contralateral thalamus → primary motor cortex → corticospinal tract → motor neurons of anterior horn
Function: participates in planning movements
summary
Cerebellar efferent fibers:
1. Globose-emboliform-rubral pathway
2. Dentothalamic pathway
3. Fastigial reticular pathway
4. Fastigial vestibular pathway
summary
Cerebellar afferent fibers:
1. Afferent fibers from cerebral cortex: corticopontocerebellar pathway.
2. Afferent fibers from spinal cord: Anterior and posterior spinocerebellar tracts
3. Afferent fibers from vestibular nerve
upper motor neuronupper motor neuron
UMNUMN
upper motor neuronupper motor neuron
UMNUMN
BASALBASALGANGLIAGANGLIABASALBASAL
GANGLIAGANGLIA
Pyramidal Tract and Associated CircuitsPyramidal Tract and Associated CircuitsPyramidal Tract and Associated CircuitsPyramidal Tract and Associated Circuits
lower motor neuronlower motor neuron
UMNUMN
lower motor neuronlower motor neuron
UMNUMN
pyramidal tractpyramidal tract
CerebellumCerebellumCerebellumCerebellum
CerebellumCerebellum FunctionFunction
CerebellumCerebellum FunctionFunction
Maintenance of EquilibriumMaintenance of Equilibrium - balance, posture, eye movement - balance, posture, eye movement
Coordination of movement ofCoordination of movement of walking and posture maintenancewalking and posture maintenance - posture, gait - posture, gait
Adjustment of Muscle ToneAdjustment of Muscle Tone
Motor Learning – Motor SkillsMotor Learning – Motor Skills
BalanceBalance
Motor Skill Motor Skill
Pablo CasalsPablo CasalsPablo CasalsPablo Casals
CerebellumCerebellum Clinical Clinical SyndromesSyndromes
CerebellumCerebellum Clinical Clinical SyndromesSyndromes
1-Ataxia1-Ataxia: incoordination of movement: incoordination of movement - decomposition of movement- decomposition of movement - tremor - tremor - past-pointing- past-pointing2- dysdiadochokinesia2- dysdiadochokinesia3-Hypotonia3-Hypotonia, , NystagmusNystagmus4- dysarthria4- dysarthria
PosturePostureGait – AtaxiaGait – Ataxia
Cerebellar Cerebellar AtaxiaAtaxia
Ataxic gait and Ataxic gait and position: position: Left cerebellar tumorLeft cerebellar tumor
a. Sways to the right ina. Sways to the right in standing positionstanding position
b. Steady on the b. Steady on the right legright leg
c. Unsteady on the c. Unsteady on the left legleft leg
d. ataxic gaitd. ataxic gait
a b c
d
Top Related