11. FUNCTION OF THE BRAINSTEM
Midbrain:
•Visual & auditory processing and reflexes
•Fine-tuning of voluntary movements
Pons:
•Relay station for cerebellum
•Control of sub-conscious movement
Medulla Oblongata:
•Control of cardiovascular functions
•Control of respiration
•Control of gastrointestinal functions
11
13. GROSS ANATOMY OF CEREBELLUMGROSS ANATOMY OF CEREBELLUM
Location:
The term cerebellum is from
“Latin meaning” the little brain.
part of the hindbrain situated in
the posterior cranial fossa.
behind the Pons and medulla
oblongata, separated from two
structures by the cavity of fourth
ventricle.
It is covered by tentorium
cerebelli and is connected to
brain stem by three cerebellar
peduncles.
In adults the weight ratio
between cerebellum and
cerebrum is 1:10,Infants 1:20
13
14. Consists of two laterally, large
hemisphere which are united by
midline vermis.
Cerebellar surface is divided by
numerous curve transverse
fissures giving it a laminated
appearance
One conspicious fissure
“horizontal fissure" extends around
dorsolateral border of each
hemisphere from middle
Cerebellar peduncle to vallecula,
separating superior and inferior
surface
Horizontal
fissure
Vermi
s
Hemisphere
Superior surface
Anatomy of cerebellum......contd.
14
15. The deepest fissure in the
vermis is primary fissure,
which curves ventrolaterally
in the superior surface of the
cerebellum to meet
horizontal fissure.
Primary fissure divides the
cerebellum into anterior and
posterior lobe.
Primary fissure
Anterior lobe
Posterior lobe
Primary fissure
External surface of cerebellum
15
17. Fourth ventricle
Arbor vitae cerebelliArbor vitae
•In Latin “ tree of life” it is
the white matter of the
cerebellum.
•It is so called because of
the tree like appearance.
•It brings sensory and
motor sensation to
and from cerebellum.
17
21. Archi-cerebellum
posterior lobe
(Vestibular part)
•It is
formed of the flocculo-nodular
lobe + associated Fastigial
nuclei, lying on inf. Surface in
front of postero-lateral fissure.
•Embryo logically, it is the
oldest part of cerebellum.
•It receives afferent Fibres.
From vestibular apparatus of
internal ear Via vestibulo-
cerebellar tracts.
•It is concerned with
equilibrium
Neocerebellum
Archicerebellum
Paleocerebellum
21
22. Paleo-cerebellum (spinal
part) •it is
formed of midline vermis +
surrounding paravermis +
globose & emboliform nuclei.
•It receives afferent
proprioceptive impulses from
Ms.& tendons Via
spinocerebellar tracts (dorsal
& ventral) mainly.
•it sends efferent to red
nucleus of midbrain.
•it is concerned with muscle
tone & posture.
Paleocerebellum
22
23. Neo-cerebellum
(cerebralpart)
•It is the remaining largest
part of cerebellum.
•It includes the most 2-
cerebellar hemispheres +
dendate nuclei.
•It receives afferent impulses
from the cerebral cortex +
Pons Via cerebroponto-
cerebellar pathway.
•it sends efferent to Ventro
lateral nucleus of thalamus.
•it controls voluntary
movements (muscle
Neocerebellum
23
24. Archicerebellum
Nodulus
Archicerebellum
flocculus
Palaeocerebell
um
Neocerebellum
Spinocerebellum
Pontocerebellum
Vestibulocerebellu
Summary of classification
24
Classification byClassification by
phylogeneticphylogenetic
Ontogenic developmentOntogenic development
• ArchicerebellumArchicerebellum
• PaleocerebllumPaleocerebllum
• NeocerebellumNeocerebellum
Classification by AfferentClassification by Afferent
ConnectionConnection
• VestibulocerebellumVestibulocerebellum
•SpinocerebellumSpinocerebellum
•Ponto cerebellumPonto cerebellum
Classification by EfferentClassification by Efferent
ConnectionConnection
•VermisVermis
•Paravermis RegionParavermis Region
•Cerebellar HemisphereCerebellar Hemisphere
27. INTERNAL STRUCTURE:-INTERNAL STRUCTURE:-
Cerebellum consists of
outer layer of grey matter
known as cortex and
inner layer of white matter
known as medulla.
The medullary core is
composed of incoming
and outgoing fibres
projecting to and from the
Cerebellar cortex.
Medullary core also
contain the nucleuses of
the cerebellum which are
four in number.
27
31. White matter of the cerebellum
Consists of three types of nerve fibres in the
white matter
A.Axons of purkinje cells
The only axons to leave Cerebellar cortex to end
in deep
Cerebellar nuclei specially dendate nucleus.
B.Mossy fibres
They end in the granular layer.
C.Climbing fibres
They end in the molecular layer 31
32. The internal circuity of cerebellum:-
Don't leave the cerebellum, interconnect
different regions of cerebellum.
Some connect the same side.
Some connect the two Cerebellar hemisphere
The Cerebellar efferent via middle Cerebellar
peduncle(MCP) and inferior Cerebellar peduncle
(ICP)
The Cerebellar afferent via superior Cerebellar
peduncle(SCP) and from Fastigial from inferior
Cerebellar peduncle(ICP)
White matter of cerebellum
32
33. The cerebellum is connected to
Brain stem by three peduncles
Midbrain
Middle Cerebellar peduncle
Pons
Inferior Cerebellar peduncle
Medulla oblongata
33
Superior Cerebellar peduncle
39. Blood supply to brain
Arch of aorta
1. Brachiocephalic trunk
i. right common carotid artery
2. Left common carotid artery
3. Left subclavian artery
right common carotid artery
1. External carotid artery
2. Internal carotid artery
39
46. Coordination of half-automatic movementCoordination of half-automatic movement
of walking and posture maintenanceof walking and posture maintenance
- posture -gait- posture -gait
46
51. Ataxia:Ataxia: incoordination of movementincoordination of movement
- decomposition of movement- decomposition of movement
- dysmetria, past-pointing- dysmetria, past-pointing
- dysdiadochokinesia- dysdiadochokinesia
- rebound phenomenon of Holmes- rebound phenomenon of Holmes
- gait ataxia, truncal ataxia, titubation- gait ataxia, truncal ataxia, titubation
Intention TremorIntention Tremor
Hypotonia,Hypotonia, NystagmusNystagmus
Archicerebellar Lesion:Archicerebellar Lesion: medulloblastomamedulloblastoma
Paleocerebellar LesionPaleocerebellar Lesion: gait disturbance: gait disturbance
Neocerebellar LesionNeocerebellar Lesion: hypotonia, ataxia, tremor: hypotonia, ataxia, tremor
SyndromeS
51
52. CerebellarCerebellar
AtaxiaAtaxia
Ataxic gait and position:Ataxic gait and position:
Left cerebellar tumorLeft cerebellar tumor
a. Sways to the right ina. Sways to the right in
standing positionstanding position
b. Steady on theb. Steady on the
right legright leg
c. Unsteady on thec. Unsteady on the
left legleft leg
d. ataxic gaitd. ataxic gait
52
53. CerebellarCerebellar
MedulloblastomaMedulloblastoma
Cerebellar tumors onCerebellar tumors on
vermisvermis
- Truncal Ataxia- Truncal Ataxia
- Frequent Falling- Frequent Falling
The child in this picture:The child in this picture:
-- would not try to standwould not try to stand
unsupportedunsupported
- would not let go of the- would not let go of the
bed railbed rail
if she was stood on theif she was stood on the
floor.floor. 53