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CEREBELLUM

BYPROF. DR. ANSARI

CHAIRPERSON ANATOMYRAK COLLEGE OF DENTAL SCIENCES

(FOR BDS SEMESTER-II STUDENTS ONLY)

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OBJECTIVES

• Parts of cerebellum

• Cerebellar peduncles

• Blood supply of cerebellum

• Functions of cerebellum

• Cerebellar lesions manifestations

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Parts of cerebellum• It has right and left cerebellar hemispheres

controlling the ipsilateral side of the body.• Both hemispheres are connected by superior and

inferior vermis.• It has three lobes:-• (a) Primary lobe/anterior lobe- controls muscle tone

& posture.• (b) secondary lobe/posterior lobe-this controls

skilled voluntary movements.• © floculonodular lobe- controls the balance.

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There are three fissures on the surfaces of cerebellum

• Fissura prima/primary fissure- it is between anterior lobe and posterior lobe

• Fissura secunda/secondary fissure-it is between posterior and floculonodular lobes

• Horizontal fissure. Runs from one middle cerebellar peduncle to the other, separating superior surface from inferior surface of cerebellum.

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Cerebellum has three peduncles

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Superior cerebellar peduncles

It is a connection between cerebellum and mesencephalon. It is an out flow tract coming out -efferent's from cerebellum.

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The inferior cerebellar peduncles

• They connect medulla and spinal cord with the cerebellum.

• They carry mainly the inputs from body.

Tuesday, April 11, 2023 10ICP

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The middle cerebellar peduncles

• It connects the cerebrum with the pons and cerebellum.

• The cerebral cortex sends fibers as cerebropontocerebellar fibers/ corticonuclear fibers/corticopontocerebellar fibers.

• It is the thickest white fibers bundles joining the pons with the cerebellum.

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MIDDLE CEREBELLAR PEDUNCLE

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Blood supply of cerebellum

• There are three arteries that supply the cerebellum:-

• I) Superior cerebellar artery-SCA.• 2) Anterior inferior cerebellar artery-AICA.• 3) Posterior inferior cerebellar artery-PICA.• These arteries arise from the vertebrobasilar

axis.

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The dentate nuclei are the deep nuclei of cerebellum, all efferent from cerebellum comes from deep nuclei

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The deep nuclei of the cerebellum

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The cerebellum is involved in the coordination of voluntary motor movement, balance and equilibrium and muscle tone.• Damage to the cerebellum can lead to: • 1) loss of coordination of motor movement (asynergia),• 2) the inability to judge distance and when to stop (dysmetria), • 3) the inability to perform rapid alternating movements

(adiadochokinesia),• 4) movement tremors (intention tremor),• 5) staggering, wide based walking (ataxic gait),• 6) tendency toward falling,• 7) weak muscles (hypotonia),• 8) slurred speech (ataxic dysarthria), and • 9) abnormal eye movements (nystagmus). 10) titubationTuesday, April 11, 2023

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References

• http://vanat.cvm.umn.edu/NeuroLectPDFs/LectCerebellum.pdf

• http://www.csuchico.edu/~pmccaffrey/syllabi/CMSD%20320/362unit7.html

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SAMPLE MCQSThe spinocerebellum contains the...

• A. vermis and intermediate zone of the anterior and posterior lobes.

• B. Vermal and floccular parts of the flocculonodular lobe.

• C. Lateral portions of the cerebellum.

• D. Posterior lobe and interposed nuclei.

• E. Anterior lobe and dentate nuclei.

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The lateral vestibular nuclei are functionally analogous to the...

• A. Red nucleus

• B. Purkinje cells

• C. Basal ganglia

• D. Thalamus

• E. Deep cerebellar nuclei

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MCQS• Following a strenuous workout with his neighborhood

team, a right-handed, 52-year-old former professional basketball player awoke the next morning with paralysis of the right lower extremity. A neurological exam revealed an exaggerated stretch reflex. There was no disturbance of position sense, pain sensation or tactile discrimination. Where is the problem localized?

• A. Anterior (ventral) horn, right side.

• B. Cerebellum, right side.

• C. Posterior (dorsal) columns of spinal cord, right side.

• D. Left motor cortex, lateral (inferior) portion of motor map.

• E. Left motor cortex, medial (superior) portion of motor

• All of the following are examples of dyskinesia EXCEPT:

• A. Athetosis

• B. Chorea

• C. Tremors

• D. Rigidity

• E. Ballismus

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