Clinical Case A patient delays initiation of movement, displays an uneven trajectory in moving her...
-
Upload
winifred-tyler -
Category
Documents
-
view
215 -
download
0
description
Transcript of Clinical Case A patient delays initiation of movement, displays an uneven trajectory in moving her...
Clinical Case A patient delays initiation of movement, displays
an uneven trajectory in moving her hand from above her head to
touch her nose, and is uneven in her attempts to demonstrate rapid
alternation of pronating and supernating movements of the hand and
forearm. Which regions of the brain ismost likely contains the
lesion? Clinical Case A 55-year-old male had been complaining about
his having difficulty in coordinating the use of his arms in
meaningful ways. For example, when examined by a neurologist, the
patient was unable to move his finger accurately to his nose from
his side when requested to do so but instead he would undershoot or
overshoot the target. He also had difficulty in makingRapid
alternating rotational movements of the hand. The neurologist
believed that the patient was suffering from a disorder that
resulted in a lesion of a region of the cerebellum or structures
related to it. Which regions of the cerebellum ismost likely
contained this lesion Cerebellum External features
located in posterior cranial fossa. 2.Communicate with brain stem
by cerebellar peduncles. Superior cerebellar peduncles( Brachium
conjunctiva) Middle cerebellar peduncles (Brachium pontis) Inferior
cerebellar peduncle (Restiform Body Crebellum External features
cont..
Anatomical sub divisions of Cerebellum Longitudinal division
Vermis, Paravermal Region, Hemisphere Transverse division Anterior
Lobe ---- primary fissure Posterior Lobe ----posterolateral fissure
Flocculonodular Lobe Cerebellum Classification
Archicerebellum(Equilibrium, Tone& Postureof trunk Muscles)
Paleocerebllum (Tone& PostureoflimbMuscles) Neocerebellum
(Smooth performance of skilled act by coordination ofmove)
Classification by itsConnections Vestibulocerebellum
Spinocerebellum cerebrocerebellum Crebellum External features
cont..
SubdivisionofFlocculonodular Lobe Nodulus Flocculus
SubdivisionofAnterior Lobe Vermis Hemisphere Lingula Central Lobule
Ala Central Lobule postcentral fissure Culmen Quadrangular Lobule
Crebellum External features cont..
SubdivisionofPosterior Lobe Vermis crebellar Hemisphere Declive
Simple Lobule postcentral fissure Folium Superior Semilunar Lobule
horizontal fissure Inferior Semilunar Lobule Tuber Gracile Lobule
prepyramidalfissure Pyramid Biventer Lobule secondary fissure Uvula
Tonsil Crebellum Internal features cont..
Cerebellar Cortex Molecular Layer Purkinje Cell Layer Granular
Layer Deep Cerebellar Nuclei Fastigial Nuclei (Nucleus
Interpositus) Emboliform Nucleus Globose Nucleus Dentate Nucleus
Crebellum Internal features cont..
Cerebellar Cortex I. Molecular Layer Stellate Cell (inhibitory)
afferent: parallel fiber efferent: Purkinje cell dendrite Basket
Cell ---- GABA (inhibitory) efferent: Purkinje cell soma Parallel
Fiber granule cell axon Purkinje Cell Dendrite Cerebellum Internal
features cont..
II. Purkinje Cell Layer Purkinje Cell -- 15,000,000 in number --
GABA (inhibitory) afferent: parallel fiber climbing fiber stellate
cell basket cell efferent: deep cerebellar nucleinuclei Cerebellum
Internal features cont..
III. Granular Layer Granular Cell -- 50,000,000,000 in number --
glutamic acid (excitatory) afferent: mossy fiber efferent: Purkinje
cell dendrite basket cell, stellate cell Golgi cell Golgi Cell --
GABA (inhibitory) afferent: parallel fiber, mossy fiber rosette
efferent: granule cell dendrite Cerebellum Internal features
cont..
Synaptic Glomerulus Afferent terminals on granular layer Mossy
Fiber Rosette -- afferent fibers except inferior olivary input --
2/3 of medullary center Granular Cell Dendrite -- main afferent
input Golgi Cell Axon -- synapse on granule cell dendrite -- GABA
(inhibitory) - Surrounded by AstrocyteFoot Process Cerebellum
Connections
1. Inferior Cerebellar Peduncle Restiform Body Posterior
Spinocerebellar Tract Olivocerebellar tract Cuneocerebellar Tract
Reticulocerebellar Tract Juxtarestiform Body Vestibulocerebellar
Tract Primary Vestyibular Fiber Cerebellum Connections
Afferent Connections (2): 2. Middle Cerebellar Peduncle
Pontocerebellar fiber Corticopontocerebellar Fiber
Reticulocerebellar Fiber 3. Superior Cerebellar Peduncle Anterior
Spinocerebellar Tract Cerulocerebellar fiber Raphecerebellar fiber
Rubrocerebellar fiber Hypothalamocerebellar fiber Cerebellum
Connections
Efferent Connections: 1. Superior Cerebellar Peduncle
Cerebellothalamic fiber - From 3 deep nuclei to VPLo, VLc, CL
Cerebellorubral fiber - From nucleus globusus And dentate nucleus
2. Inferior Cerebellar Peduncle Fastigiovestibular fiber Descending
portion of Uncinate fasciculus Cerebellar Pathway Main Connections
of the Vestibulocerebellum
Vestibular Organ Floculonodular Lobe Vermis VESTIBULAR NUCLEUS
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
PALEOCEREBELLUM SPINAL CORD spinocerebellartract Main Connections
of the Neocerebellum
CEREBRAL CORTEX THALAMUS DENTATE NUCLEUS pyramidal tract Pontine
Nucleus POSTERIOR LOBE CEREBELLAR HEMISPHERE lower motor neuron
NEOCEREBELLUM LMN Pyramidal Tract and Associated Circuits
upper motor neuron UMN Cerebellum BASAL GANGLIA pyramidal tract
lower motor neuron UMN Cerebellum and Automatic Motor Control Lower
Motor Neuron (LMN)
Motor Cortex CEREBELLUM Red Nucleus Vestibular Nucleus Reticular
Formation Lower Motor Neuron (LMN) Proprioceptors Functions Of
Cerebellum
Maintenance of Equilibrium - balance, posture, eye movement
Coordination of automatic movement of walking and posture
maintenance - posture, gait Adjustment of Muscle Tone Motor Leaning
Motor Skills Cognitive Function Cerebellum Disorders Ataxia:
incoordination of movement
- decomposition of movement - dysmetria, past-pointing -
dysdiadochokinesia(Adidydakokinesia) - rebound phenomenon of Holmes
- gait ataxia, truncal ataxia, titubation Intention Tremor
Hypotonia, Nystagmus Cerebellum Disorders Archicerebellar Lesion:
medulloblastoma
Paleocerebellar Lesion: gait disturbance Neocerebellar Lesion:
hypotonia, ataxia, tremor