Cerebellum

Done by

Dr. Rafid Remthan Al -Temimi
Clinical Radiology
CAMB,DMRD, M.B.Ch.B .,.
المرحلة : الثانية
المادة : التشريح
امعة ذي قار ج/ كلية الطب
الدكتور
رمثان التميمي رافد

CEREBELLUM

In posterior fossa
University Of Thi -Qar
College Of medicine
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi

Ce r ebell u m

foss a , a n d co nsi sts of
• It oc cup ie s th e p o sterio r cra n ial
tw o
hemispheres united in the midline
by the vermis .
• Th re e pe d uncles co nn e ct each
hemisphere to the three parts of the brainstem.
• The superior peduncle enters the
midbrain,
• th e middl e pe d uncle co nsi sts of the transverse
fibres of the pons
• th e in ferio r pe d uncle co nn e ct s it
to the medulla.
• The ventral surface of the vermis
lies up o n th e ro o f of th e 4 th
ventricle …
• 1 - the superior medullary velum
• 2 - the inferior medullary velum
1
2
University Of Thi -Qar
College Of medicine
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi

Ce r ebell u m

• Sepa rat e from th e ce rebr u m b y the
tentorium ..
• sh a llow sulci a n d foli a e
( equivalent to gyri in cerebrum ) !!
• Question You Should Answer After
Complete Reading The Lecture !!
• WHY cerebrum cerebellum ratio in neonates
is 1 :20 while in adults is 1 :8 ?!
1
2
University Of Thi -Qar
College Of medicine
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi

Ce r ebell u m

• Arbor viti cerebelli : the white mater of
cerebellum run from and to the cortex ..

• SO,

• Cortex = grey mater
• Arbor veli cerebelli = white mater
• Is th e re is o ther g re y m at e r in
cerebellum ?!
• YES
• 4 n u cle i emb e d d e d in the w h ite
mater ( to some extent it resemble
the Basal ganglia as the letter embedded
within white mater but it is a grey mater
rather than the cortex )
1
2
University Of Thi -Qar
College Of medicine
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi

Fissu r es

1 . Primary fissure
- V shaped.
- Sepa rat e th e a n terio r lo b e from
the posterior ( middle ) lobe.
2 . Horizontal fissure
- Deepest one.
- Separate the cerebellum to uppe and lower
portios.
r

e
3 . Uvulonodular fissure
• Separate the middle lobe from th
flocculonodular lobe.
1
2
2
3
2
University Of Thi -Qar
College Of medicine
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi

Lobes

1. Anterior lobe
2. Posterior ( middle lobe )
3. Flocculonodular lobe
1

2
3
University Of Thi -Qar
College Of medicine
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi

V ermis

• Disk like structure divided int o
regions as seen in sagggital
sections.
co nn e cte d to • This regions are o ther
region s in th e cerebellum
forming the usual structure of this
organ.
• Primar y fissu re di v e d it int o superior
and inferior portions !!
University Of Thi -Qar
College Of medicine
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi

Cerebellar nuclei

th rough
• 1 - dentate nucleus
- Medial to the center
- Most efferent fibers go
superior cerebellar peduncle
• 2 - nucleus emboliformis
- At the medial side of dentate nucleus
• 3 - nucleus globosus
- To the medial of nucleus emboliformis
• 4 - fastigial nucleus
- Larger than other two .. ( 2 +3 )
- Situ ate d near the midli n e at the anterior
end of superior vermis
- 2 +3 = interposed nucleus !!
1
3
2
4
University Of Thi -Qar
College Of medicine
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi

Functional parts of the cerebellum

Vetibulocerebellar
spinocerebellar
Cerebrocerebellar
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

Extrapyramidal system ?

University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

Extrapyramidal system tracts

Input Nuclei Tract Termination
( anterior horn
cells )
Function
- Cerebellum
( opposite side )
- Motor cortex (
same side )
Red nucleus Rubrospinal Cervical spinal
cord
Control the
muscle tone
- Cerebellum
- Cortex
Reticular
form ation
nuclei
Reticulospinal Anterior horn
cells
Locomotion
and posture
control
- Cerebellum
- Brainstem
- Spinal cord
Inferior
olivary
nu cleus
Olivospinal Anterior horn
cells
Control reflexes
- Retina
- Cortex
Supe ri or
colliculi
Tectospinal Cervical spinal
cord
Body response to
visual stimuli
- Vestibular
nerve
Vestibular
nuclei
Vestibulospinal Anterior horn
cells
Maintaining
balance of the
body
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

Vestibulocerebllum ( Archycerebellum )

P art
Vetib u loce rebellum (
Archicerebellum )
P osi ton Flocculonodular lobe
+ part of the vermis
Ce rebellar
Nucleus
Fastigial n .
Connection Vestibular n.
Tract Vetibulospinal
Fu ncti o n Balance in spatial
orientation
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

spinocerebllum ( palocerebellum )

P art
spinocerebellum
( palocerebellum )
P osi ton Vermis + paravermis
zone
Cerebellar
Nucleus
Interposed n. (
globosus +
emboliformis )
Connection • DC
• Sp in o ce re b ellar
system
Tract Rubrospinal
R eticulospi n al
Fu ncti o n Tone and fine
tuning
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

cerebrocerebllum ( neocerebellum )

P art
cerebrocerebellum (
neocerebellum )
P osi ton Lateral part of hemisphere
Ce rebellar
Nucleus
Dentate n.
Connection • Cerebral cortex
• thalamus
Tract Corticospinal
Fu ncti o n - Planning movemen
- Evalu ation the se n so ry
information for action
- Cognitive and speech
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

Connections inside the cerebellum

• Two main input fibers excitatory to
purkinje cell …
• 1 - climbing fibers
- From olivary n.
- Ascend to molecular layer to synapse with
dendrites of purkinje cell .
- A single Purkinje neuron makes synaptic
contact with only one climbing fiber
- 2 - mossy fibers
- the terminal fibers of all other
cerebellar afferent tracts .
- exert a much more diffuse excitatory
effect .
- A single mossy fiber may stimulate
thousands of Purkinje cells through the
granule cells
Efferent to
cerebellar nuclei
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

Cerebellum inputs

Area Fibers Function
1 Cortex Cortico -ponto -cerebellar Cortico -
olivo cerebellar
Cortical control
2 Posterior horn cells of
spinal cord
Anterior and posterior
spinocerebellar tract
Information from
muscle and joints
3 Cuneate nucleus Cuneocerebellar Information from
muscle and joints
4 Vestibular nuclei Vestibulocerebellar Information about head
position and eye movement
Ce rebe llum
Spinal cord Brainstem Cortex
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd stage Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

Cerebellum outputs

Area Fibers Function
1 Contralateral red
nucleus
Cerebellorubral Ipsilateral motor
activity
2 Thalamus Dentato -thalamic Ipsilateral motor
activity
3 Vestibular nuclei Cerebellovestibular Ipsilateral extensor
muscle tone
4 Reticular formation Cerebelloreticular Ipsilateral muscle tone
Thalamus brainstem
Cerebellum
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

Blood supply to cerebellum

1. Posterior inferior cerebellar artery (
vertebral a. )
2. Anterior inferior cerebellar
artery ( basilar a. )
3. Superi o r ce rebell a r ar te ry (
basilar a. )
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

Superior cerebellar peduncle

• Con n ec t ce rebell u m to midbrain
• Main output from cerebellum
( efferent )
• Small afferent !!
• Efferent :-
1. Cerebello -rubral fibers
2. Dentato -thalamic fibers
3. Cerebello -vestibular fibers
• Afferent fibers
• Anterior spinocerebellar tract
• tri g emin o th al a mi c fibe rs (
proprioceptive information
• tectocerebellar fibers ( auditory
and visual information )
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

middle cerebellar peduncle

• Connect cerebellum to pons
• Main input to cerebellum !!
• Comp o sed e xclusi vel y from cortico -
ponto -cerebellar fibers .
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

Inferior cerebellar peduncle

• Con n ec t th e ce rebell u m to
medulla oblongata ..
• Efferent :-
• Cerebello -olivary fibers
• Cerebello reticular fibers
• Afferent :-
• Posterior spinocerebellar fibers
• Cuneocerebellar fibers
• Reticulocerebellar
• Vestibulocerebellar
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

Functions of the cerebellum

• Afferent information about
• Voluntary movement
• Balance
• Site
will enter to cerebellum !!
• The output of the vermis projects to the
fastigial nucleus,the intermediate regions
of the cortex project to the globose and
emboliform nuclei, and the output of the
lateral part of the cerebellar hemisphere
projects
to the de nt a te n u cleu s .. AS
PR E VIOU S IN MEN TIO N ED
LECTURE !!
• A fe w P u rkinj e cel l a xo n s p a ss directly
out of the cerebellum.
• Purkinje axons are inhibitory !!
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

• Cerebellum exerts its influence indirectly through the cerebral cortex and brainstem ( not
connect to anterior horn cells ) !!
• the cerebellum functions as a coordinator of precise movements by continually comparing the
output of the motor area of the cerebral cortex with the proprioceptive information received
from the site of muscle action ; it is then able to bring about the necessary adjustments by
influencing the activity of the lower motor neurons
• This is accomplished by controlling the timing and sequence of firing of the motor neurons .
Functions of the cerebellum
University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020

• It is also beli e v e d th a t th e

cerebellum
in form a ti o n
ca n
to
send b a ck
the moto r
cerebral cortex
a g o n ist muscles the
antagonist
to inhibit th e and
stimulat muscles,
thu s
limiti n g th e e x te n t of v ol u nt ar y
movement.
University Of Thi -Qar
College Of medicine
Dr.Rafid Remthan AL -Temimi,Clinical Radiology,CAMB , 2020
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi

Thank you

University Of Thi -Qar
College Of medicine
Anatomy lecture . 2nd stage
Dr.Rafid Al -Temimi