Cerebellum

1. CEREBELLUM BY PROF. DR. ANSARI CHAIRPERSON ANATOMY RAK COLLEGE OF DENTAL SCIENCES (FOR BDS SEMESTER-II STUDENTS ONLY) Friday, May 10, 2013 1

2. OBJECTIVES Parts of cerebellum Cerebellar peduncles Blood supply of cerebellum Functions of cerebellum Cerebellar lesions manifestations Friday, May 10, 2013 2

3. 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. Friday, May 10, 2013 3

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6. 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. Friday, May 10, 2013 6

7. Friday, May 10, 2013 7 Cerebellum has three peduncles

8. Superior cerebellar peduncles It is a connection between cerebellum and mesencephalon. It is an out flow tract coming out -efferent's from cerebellum. Friday, May 10, 2013 8

9. The inferior cerebellar peduncles They connect medulla and spinal cord with the cerebellum. They carry mainly the inputs from body. Friday, May 10, 2013 9

10. Friday, May 10, 2013 10 ICP

11. 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. Friday, May 10, 2013 11

12. Friday, May 10, 2013 12 MIDDLE CEREBELLAR PEDUNCLE

13. 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. Friday, May 10, 2013 13

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15. The dentate nuclei are the deep nuclei of cerebellum, all efferent from cerebellum comes from deep nuclei Friday, May 10, 2013 15

16. The deep nuclei of the cerebellum Friday, May 10, 2013 16

17. 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) titubation Friday, May 10, 2013 17

18. References http:// vanat.cvm.umn.edu/NeuroLectPDFs/LectCerebellum.pdf http://www.csuchico.edu/~ pmccaffrey/syllabi/CMSD%20320/362unit7.html Friday, May 10, 2013 18

19. SAMPLE MCQS The 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. The lateral vestibular nuclei are functionally analogous to the... A. Red nucleus B. Purkinje cells C. Basal ganglia D. Thalamus E. Deep cerebellar nuclei Friday, May 10, 2013 19

20. 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 Friday, May 10, 2013 20