Faculty of Dental Medicine and Surgery Sem 4 Cerebellum Dr. Abbas
Anatomy of the cerebellum
Cerebellum Configurations External - located in posterior cranial fossa - communicate with other structure via superior, middle, and inferior cerebellar peduncle - longitudinal division Vermis, Paravermal Region, Cerebellar Hemisphere - transverse division Anterior Lobe ------------ primary fissure Posterior Lobe ------------ posterolateral fissure Flocculonodular Lobe
Cer ebellmn Stl}Jetior Stuface Roatral(anter lor) lohe lobule A-rt:erior cerebellar notch adrangular Central lobule of superior vermi Primary fissure...- - - - - - Horizontal fissure,...----simplex lobule eclive of superior vermi Postlunate fissure Rostral (superior) semilunar lobule Folium of superior vermis dal Onferior) semilunar lobule Posterior cerebellar notch Caudal (posterior)lobe r ra / % e Clfift-GEIGV
f erebellmn Infetior Stuface Flocculonodular lobe Ungula of superior verm Superior medullary vel Central lobule of superior verm of central lobule uperior cerebellar peduncle Mddle cerebellar peduncle nferior cerebellar peduncle Dorsolateral (posterolateral) fissure audal Onferior) semilunar lobule Tuber of inferior vermi Posterior cerebellar notch econdary (postpy ramidal) fissure Cauda l (posterior) lobe r L ;, f$ e ClfiA-GEIG'{
Anatomy of the cerebellum Forms roof of 4th ventricle Lobes of cerebellum: anterior, posterior, flocculonodular Primary fissure; tonsil Nolte 20-2d; DE Haines 382c
Cerebellar divisions Spinocerebellum (Vermis + Intermed. Hem) Control of limbs and trunk Cerebrocerebellum (Lateral hemisphere) Planning of movement+ Vestibulo-cerebellum (Floculo-nodular lobe) Control of eye & head movements Balance IVth vent Spinocerebellum: Vermis Intermediate hem. Cerebrocerebellum: Lateral hem. Vermis Intermediate hem. Lateral hem. NTA Fig. 13-1 Floculo-nodular lobe
Indirect influence on LMNs Thalamus Cortex UMN (CST) Cerebellum UMN CNS LMN Cerebellum directly or indirectly influences UMN systems that control LMNs PNS muscle
DE Haines. 380 A, B Cerebellar peduncles
Inferior cerebellar peduncle DeArmond 89
Middle cerebellar peduncle
Superior cerebellar peduncle DeArmond 99, 105
Cerebellmn Sectio11it1Pla11e of SU}Jetior C erebellar Pedtn1cle Decussation o1 superior cerebellar peduncles Cerebral peduncle Superior medullary vel Fa:::tigial nucleus 4th ventricl / Medi llong udin l f sciculus Nuclear layer of medulla oblongata Superior cerebellar peduncle Globose nuclei nucleus Dentate nucleus is
Deep Nuclei 1. fastigial nucleus 2. globos e nucleus 3. embolifor m nucleus 4. dentate nucleus
Main Connections of the Vestibulocerebellum Vestibular Organ VESTIBULAR NUCLEUS Floculonodular Lobe Vermis vestibulospinal tract MLF FASTIGIAL NUCLEUS lower motor neuron ARCHICEREBELLUM LMN
Main Connections of the Paleocerebellum RED NUCLEUS NUCLEUS INTERPOSITUS rubrospinal tract Inferior Olivry Nucleus ANTERIOR LOBE PARAVERMAL ZONE lower motor neuron SPINAL CORD spinocerebellar tract PALEOCEREBELLUM
Main Connections of the Neocerebellum CEREBRAL CORTEX THALAMUS DENTATE NUCLEUS pyramidal tract Pontine Nucleus POSTERIOR LOBE CEREBELLAR HEMISPHERE lower motor neuron LMN NEOCEREBELLUM
Cerebellar cortex Three layers: Molecular, Purkinje, Granular Wheater 370 DE Haines 386
T he im age cannot be display ed. Y our com puter may not hav e enough mem ory to open the im age, or the im age m ay hav e been corrupted. Restart y our com puter, and then open the file again. If the red x still appears, y ou may hav e to delete the im age and then insert it again. Cerebellar Cortex Inputs Climbing fibers from Inferior olive Mossy fibers Output Purkinje neurons Interneurons Granule neurons Stellate neurons Basket neurons Molecular Golgi neurons Purkinje Granular NTA Fig. 13-11
Layers Cerebellar cortex: cell types, connections Molecular Cell types -basket, stellate -Purkinje project to deep nuclei -Granule, Golgi Purkinje Granular Fibre types -Climbing (from inferior olive, direct to Purkinje) -Mossy (all other input, to granule cells, which project to Purkinje neurons)
Blood supply of the cerebellum
Damage to the cerebellum Ataxia: uncoordinated movement Muscles tend to be hyporeflexic, hypotonic Midline damage (vermis/fastigal) causes ataxia of trunk musculature Lateral damage (paravermis/interposed and lateral/dentate) causes ipsilateral ataxia of limbs Intension (action) tremor Dysmetria (inaccurate reaching) Decomposition of movement Dysdiadochokinesia (inability to perform rapid alternating movements)
a b c Cerebellar Ataxia d 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
Diseases affecting the cerebellum Tumours (medulloblastoma or astrocytoma) Strokes (hemorrhagic or ischemic) Alcoholism (malnutrition, thiamine deficiency) Spinocerebellar degeneration Netter 24 CIBA Collection