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The Cerebellum. Position Lies above and behind the medulla and pons and occupies posterior cranial fossa Its surface is high convoluted, forming folds.

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Presentation on theme: "The Cerebellum. Position Lies above and behind the medulla and pons and occupies posterior cranial fossa Its surface is high convoluted, forming folds."— Presentation transcript:

1 The Cerebellum

2 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

3 External features Consists of two cerebellar hemisphere united in the midline by the vermis

4 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

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6 External features Tonsil of cerebellum two elevated masses on inferior surface of hemispheral portion just nearby foramen magnum

7 Lobes Two deep fissures  Primary fissure  Uvulonodular fissure Three lobs  Flocculonodular lobe  Anterior  Posterior lobe

8 Lobes Primary fissure Posterolateral fissure Flocculonodular lobe Anterior lobe Posterior lobe corpus of cerebellar

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10 Internal structures Gray matter Cerebellar cortex Cerebellar nuclei  Dentate nucleus  Fastigial nucleus  Emboliform nucleus  Globose nucleus White matter

11 Internal structures Cerebellar cortex Dentate nucleus Fastigial nucleus Globose nucleus Emboliform nucleus medullary center

12 1. fastigial nucleus nucleus 2. globose nucleus nucleus 3. emboliform nucleus nucleus 4. dentate nucleus nucleus Deep Nuclei

13 Three functional divisions Vestibulocerebellum  Archicerebellum  Flocculonodular lobe Spinocerebellum  Paleocerebellum  Vermis and intermediate zone Cerebrocerebellum  Neocerebellum  Lateral zone Flocculonodular lobe Vermis Intermediate zone Lateral zone

14 IV th vent Vermis Intermediate 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 movements Balance Cerebellar divisions

15 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

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17 Connections and function of cerebellum Spinocerebellum Connnection  Afferents: receive somatic sensory information via spinocerebellar tracts

18  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

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20 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

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23 summary Cerebellar efferent fibers: 1. Globose-emboliform-rubral pathway 2. Dentothalamic pathway 3. Fastigial reticular pathway 4. Fastigial vestibular pathway

24 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

25 upper motor neuron UMN UMN BASALGANGLIABASALGANGLIA Pyramidal Tract and Associated Circuits lower motor neuron UMN UMN pyramidal tract CerebellumCerebellum

26 Cerebellum Function Cerebellum Function  Maintenance of Equilibrium - balance, posture, eye movement - balance, posture, eye movement  Coordination of movement of walking and posture maintenance walking and posture maintenance - posture, gait - posture, gait  Adjustment of Muscle Tone  Motor Learning – Motor Skills

27 Balance

28 Motor Skill Pablo Casals

29 Cerebellum Clinical Syndromes Cerebellum Clinical Syndromes 1-Ataxia: incoordination of movement - decomposition of movement - decomposition of movement - tremor - tremor - past-pointing - past-pointing 2- dysdiadochokinesia 3-Hypotonia, Nystagmus 4- dysarthria

30 Posture Gait – Ataxia

31 CerebellarAtaxia Ataxic gait and position: Left cerebellar tumor Left cerebellar tumor a. Sways to the right in a. Sways to the right in standing position standing position b. Steady on the b. Steady on the right leg right leg c. Unsteady on the c. Unsteady on the left leg left leg d. ataxic gait d. ataxic gait abc d


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