3. It is also present behind the pons and medulla ablongata,seperated from two structures by the cavity of fourth ventricle.
4. It is covered by tentoriumcerebelli and is connected to brain stem by three cerebellar peduncles.
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6. Cerebellar surface is divided by numerous curve transverse fissures giving it a laminated appearance
7. One conspicious fissure “horizontal fissure”extends around dorsolateral border of each hemisphere from middle cerebellar peduncle to vallecula,seperating superior and inferior surfaceHemisphere Superior surface Vermis
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9. Primary fissure divides the cerebellum into anterior and posterior lobe.Anterior lobe Primary fissure Posterior lobe
11. Arbor vitae cerebelli Arbor vitae •In latin “ tree of life” it is the white matter of the white matter of cerebellum. •It is so called because of the tree like appearance. •It brings sensory and motor sensation to and from cerebellum. Fourth ventricle
12. The cerebellum is connected to Brain stem by three peduncles Superior cerebellar peduncle Midbrain Middle cerebellar peduncle Pons Inferior cerebellar peduncle Medulla ablongata
22. Afferent vestibular Fibres. Pass from vestibular nuclei in pons & medulla to the cortex of ipsilateralflocculo-nodular lobe.
23. Efferent cortical (purkinje cell) Fibres. Project to fastigial nucleus, which projects to vestibular nuclei & reticular formation.
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26. . Afferents spinal Fibresconsist of dorsal & ventral spino-cerebellar tract from muscle, joint & cutaneous receptors to enter the cortex of ipsilateralvermis & paravermis Viainferior & superior cerebellar peduncles .
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29. It receives afferents from cerebral cortex involved in planning of movement- to pontine nuclei ,cross to opposite side Via middle Cerebellar peduncle to end in lateral parts of cerebellum (cerebro-ponto-cerebellar tract).
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31. Summary of classification Archicerebellum Nodulus Classification by phylogenetic Ontogenic development Archicerebellum Paleocerebllum Neocerebellum Classification by Afferent Connection Vestibulocerebellum Spinocerebellum Pontocerebellum Classification by Efferent Connection Vermis Paravermal Region Cerebellar Hemisphere Archicerebellum flocculus Palaeocerebellum Neocerebellum Spinocerebellum Pontocerebellum Vestibulocerebellum
33. Subdivision of lobes Subdivision of Flocculonodular lobe Flocculus Nodulus Subdivision of Anterior lobe Lingula Ala of central lobule Central lobue l
70. Functions of cerebellum Maintenance of Equilibrium - balance, posture, eye movement Coordination of half-automatic movement of walking and posture maintenace - posture, gait Adjustment of Muscle Tone Motor Leaning – Motor Skills Cognitive Function
73. Syndromes Ataxia:incoordination of movement - decomposition of movement - dysmetria, past-pointing - dysdiadochokinesia - rebound phenomenon of Holmes - gait ataxia, truncal ataxia, titubation Intention Tremor Hypotonia,Nystagmus Archicerebellar Lesion: medulloblastoma Paleocerebellar Lesion: gait disturbance Neocerebellar Lesion: hypotonia, ataxia, tremor
74. Cerebellar Ataxia Ataxic gait and position: Left cerebellar tumor a. Sways to the right in standing position b. Steady on the right leg c. Unsteady on the left leg d. ataxic gait
75. CerebellarMedulloblastoma Cerebellar tumors on vermis - Truncal Ataxia - Frequent Falling The child in this picture: - would not try to stand unsupported - would not let go of the bed rail if she was stood on the floor.
76. Cerebellar lesions Are usually vascular, may be traumatic or tumour. Manifestations of unilateral cerebellar lesions :1-ipsilateral incoordination of (U.L) arm= intention tremors : it is a terminal tremors at the end of movement as in touching nose or button the shirt. 2-Or ipsilateralcerebellar ataxia affects (L.L.) leg, causing wide-based unsteady gait. Manifestations of bilateral cerebellar lesions (caused by alcoholic intoxication, hypothyrodism, cerebellar degeneration & multiple sclerosis) 1-dysarthria : slowness & slurring of speech. 2-Incoordination of both arms.=intention tremors. 3-Cerebellar ataxia : intermittent jerky movements or staggering ,wide-based, unsteady gait 4-Nystagmus : is a very common feature of multiple sclerosis. It is due to impairment coordination of eye movements /so, incoordination of eye movements occurs and eyes exhibit a to-and-fro motion. Combination of nystagmus+ dysarthria+ intension tremors constitutes Charcot’triad, which is highly diagnostic of the disease.