The cerebellum is located in the posterior cranial fossa. It consists of two hemispheres united by a midline vermis. The cerebellum receives inputs from the cerebral cortex, spinal cord, and vestibular system. It is divided into three lobes - the archicerebellum, paleocerebellum, and neocerebellum - which are involved in balance, muscle tone, and voluntary movement coordination respectively. The cerebellar cortex has three layers - molecular, purkinje cell, and granular. Purkinje cells are the main output neurons. The cerebellum regulates posture, balance, and muscle coordination through its connections with the brainstem and thalamus.

1. CEREBELLUM

2. GROSS ANATOMY OF CEREBELLUM
Location:
 The term cerebellum is from “latin
meaning” the little brain.It is a
part of the hindbrain situated in the
posterior cranial fossa.
 It is also present behind the pons
and medulla ablongata, seperated
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

3.  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,
seperating superior and inferior
surface

4.  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.

5. Vermis
• The cerebellar vermis (Latin for worm) is
located in the medial, cortico-nuclear zone
of the cerebellum, residing in the posterior
fossa of the cranium. The primary fissure in
the vermis curves ventrolaterally to
the superior surface of the cerebellum,
dividing it into anterior and posterior lobes.
Functionally, the vermis is associated with
bodily posture and locomotion.

7. Cerebellar Hemispheres
• Each hemisphere
consists of lobes
separated by deep and
distinct fissures.
• The anterior lobe and
posterior lobe govern
subconscious aspects of
skeletal muscle
movements.
• The flocculonodular lobe
on the inferior surface
contributes to
equilibrium and balance.

8. Cerebral Nuclei
• Dentate
• Emboliform
• Festigial
• Globose

9. Dentate Nucleus
The dentate nucleus is a
cluster of neurons, or nerve
cells, in the central nervous
system that has a dentate –
tooth-like or serrated –
edge. It is located within the
deep white matter of each
cerebellar hemisphere, and
it is the largest single
structure linking the
cerebellum to the rest of the
brain.

10. Emboliform Nucleus
The emboliform
nucleus (or anterior
interposed nucleus) is
a deep cerebellar
nucleus that lies
immediately to
the medial side of
the nucleus dentatus,
and partly covering
its hilum.

11. Fastigial Nucleus
• The fastigial nucleus is located in
the cerebellum. It is one of the four deep
cerebellar nuclei and is grey matter embedded
in the white matter of the cerebellum.
• It refers specifically to the concentration of
gray matter nearest to the middle line at the
anterior end of the superior vermis, and
immediately over the roof of the fourth
ventricle, from which it is separated by a thin
layer of white matter

12. Globose Nucleus
• The globose nucleus is one of the deep
cerebellar nuclei. It is located medial to
the emboliform nucleus and lateral to
the fastigial nucleus. This nucleus contains
primarily large and small multipolar
neurons.

13. Fourth
ventricle
Arbor vitae
cerebelli
Arbor vitae
•In latin “ tree of life” it is the white matter
of the white matter of cerebellum.
•It is so called because of the tree like
appearance.
•It brings sensory and motor
sensation to and from cerebellum.

14. Cerebellar peduncles
• Cerebellar peduncles connect the
cerebellum to the brain stem.
• Superior cerebellar peduncle is a paired
structure of white matter that connects
the cerebellum to the midbrain.
• Inferior cerebellar peduncle is a thick rope-
like strand that occupies the upper part of the
posterior district of the medulla oblongata.
• Middle cerebellar peduncles connect
the cerebellum to the pons and are composed
entirely of centripetal fibers.

15. The cerebellum is connected
to
Brain stem by three
peduncles
Superior cerebellar peduncle
Midbr
ain
Middle cerebellar peduncle
Pon
s
Inferior cerebellar peduncle
Medulla
ablongata

16. Peduncles of the cerebellum

17. LOBES OF CEREBELLUM
Anatomical
Anterior lobe
Posterior lobe
Flocculonodular lobe
Superior surface

18. Archicerebellum
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.
• Embryologically, 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 equlibrium

19. Archicerebellum …….contd.
 It has connections with vestibular &
reticular nuclei of brain stem through
the inferior cerebellar peduncle.
 Afferent vestibular Fibres. Pass from
vestibular nuclei in pons & medulla to
the cortex of ipsilateral flocculo-nodular
lobe.
 Efferent cortical (purkinje cell) Fibres.
Project to fastigial nucleus (It is one of
the four deep cerebellar nuclei and is
grey matter embedded in the white
matter of the cerebellum), which
projects to vestibular nuclei & reticular
formation.
 It affects the locomotror system
bilaterally via descending vestibulo-
spinal & reticulo-spinal tracts.
Sub – divisions
Vermis:- Nodulus
Hemispheres:- Fluocculus and
parafuocculus

20. Paleocerebellum
(spinal part)
• It is formed of midline vermis +
surrounding paravermis + globose &
emboliform nuclei.
• It receives afferent proprio-ceptive
impulses from Ms.& tendons Via spino-
cerebellar tracts (dorsal & ventral)
mainly.
• It sends efferents to red nucleus of
midbrain. (The red nucleus or nucleus
ruber is a structure in the
rostral midbrain involved in motor
coordination. It is pale pink in color; the
color is believed to be due to iron, which
is present in the red nucleus in at least
two different forms
: hemoglobin and ferritin)
• It is concerned with muscle tone

21.  It is concerned with muscle tone &
posture.
 Afferents spinal Fibres consist of
dorsal & ventral spino-cerebellar
tract from muscle, joint & cutaneous
receptors to enter the cortex of
ipsilateral vermis & para vermis Via
inferior & superior cerebellar
peduncles .
 Efferents cortical fibres pass to
globose & emboliform nuclei, then
Via sup. C. peduncle to contra-
lateral red nucleus of midbrain to
give rise descending rubro-spinal
tract (motor control pathway)
Sub – divisions
Vermis:- Lingula, Columen
Hemispheres:- Central Lobule and
anterior quadrang lobule

22. Neo-cerebellum
(cerebral part)
• 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 cerebro-
ponto- cerebellar pathway.
• It sends efferents to Ventro
lateral nucleus of thalamus.
• It controls voluntary
movements (muscle
coordination).

23.  It is concerned with muscular
coordination.
 It receives afferents from cerebral cortex
involved in planning of movement- to
pontine nuclei ,cross to opposite side Via
middle Cerebellar peduncle to end in
lateral parts of cerebellum (cerebro-ponto-
cerebellar tract).
 Neo-cerebellar efferents project to
dendate nucleus,which in turn projects to
contra-lateral red nucleus & ventral lateral
nucleus of thalamus ,then to motor cortex
of frontal lobe, giving rise descending
cortico-spinal & cortico-bulbar pathways.
 Efferents of dentate nucleus form a major
part of Superior cerebellar peduncle.
Sub – divisions
Vermis:- Declive, Folium, tuber, pyramis,
uvula
Hemispheres:- Simple lobule, superior
semilunar lobule, superior semilunar lobule,
Gracile lobule ,Biventral lobule, Tonsil

24. Cerebellar Cortex
• Molecular Layer
• Purkinje Cell Layer
• Granular Layer

25. CEREBELLUM CORTEX
1. Molecular Layer
a. Stellate Cell:- taurine
(inhibitory)
afferent: parallel fiber
efferent: Purkinje cell dendrite
b. Basket Cell :- GABA
(gamma-aminobutyric
acid)(inhibitory)
(Inhibit or reduce the activity of the neurons or nerve cells)
afferent: parallel fiber
efferent: Purkinje cell soma
c. Parallel Fiber
granule cell axon
d. Purkinje Cell Dendrite

26. 2. Purkinje Cell Layer
Purkinje Cell
• 15,000,000 in number
• GABA (inhibitory)
• afferent:
– parallel fiber
– climbing fiber
– stellate cell
– basket cell
• efferent:
– deep cortical nuclei
Bergman’s glial cell

28. Purkinje cells
flaskshaped cell, single layered
Dendrites
–Molecular layer
–Profuse branching
–Dendritic spines
Axon
– synapse with deep cerebellar
nucleus
– basket & stellate cells
– vestibular nuclei

29. 3.Granular Layer
Granular Cell
• 50,000,000,000 in number
• glutamic acid (excitatory)
• afferent: mossy fiber
• efferent: Purkinje cell axon,
basket cell, stellate cell
Golgi cell
GABA (inhibitory)
• afferent: parallel fiber,
mossy fiber rosette
• efferent: granule cell
dendrite

30. Climbing fibres
- from inferior olivary complex
- direct action on individual Purkinje cell
-powerful , sharply localised
-- Basket cells, stellate cells, Golgi cells act
as inhibitory interneurons.
Mossy fibres
-from spinal cord / brain stem centres
-indirect action on Purkinje cells via
granule cells
-diffuse
( thousands of Punkinje cells may be excited )

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

32. White matter of cerebellum
 The internal circuitry of cerebellum
 Do not 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)

33. Intrinsic pathway
• Afferent pathways to cerebellar cortex
excite Purkinje cells.
• Basket, stellate and Golgi cells regulate
Purkinje cell activity
• Efferent pathways from the cerebellar
cortex originate from Purkinje cells -

36. Cerebellar afferent pathway
From cerebral cortex
cortico-ponto-cerebellar fibres
cerebro-olivo-cerebellar fibres
cerebro- reticulo- cerebellar fibres
From spinal cord
anterior spinocerebellar tract
posterior spinocerebellar tract
cuneocerebellar tract
From vestibular nucleus
vestibulocerebellar tract [
flocculonodular lobe ]
From other areas
red nucleus, tectum

37. Afferent pathway origin Destination via
Corticopontocerebellar
Frontal, parietal,
temporal, occipital
Pontine nuclei & mossy
fibres to cerebellar
cortex
Cerebroolivocerebellar
climb fibres to
cerebellar cortex
Cerebroreticulocerebellar Sensorimotor areas Reticular formation
Ant spinocerebellar
Muscle
spindles,tendons,
joints
Mossy fibres to
cerebellar cortex
Post spinocerebellar
Cuneocerebellar
Vestibular nerve
Utricle,
saccule,semicircular
canals
Mossy fibres to cortex
of FN node
others Red nuc, tectum cerebellar cortex

38. Cerebellar efferent pathways
• Axons of Purkinje cells
synapse with the cerebellar nuclei.
• Axons of the neurones form the
efferent pathways
Connect with
• Red nucleus
• Thalamus
• Vestibular nuclei
• Reticular formation

39. Cerebellar cortex…..contd.
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 Astrocyte

40. Fibres entering and leaving through cerebellar peduncles
Superior cerebellar peduncle
A. Fibres entering the cerebellum
1. Ventral spino-cerebellar tract
2. Rostral spino-cerebellar tract
3. Tecto-cerebellar fibres
4. Rubro-cerebellar fibres
5. Trigemino-cerebellar fibres
6. Hypothalamo-cerebellar fibres
7. Coerulo-cerebellar fibres
B. Fibres leaving the cerebellum
1. Cerebello-rubral fibres
2. Cerebello-thalamic fibres
3. Cerebello-reticular fibres
4. Cerebello-olivary fibres
5. Cerebello-nuclear fibres
6. Some fibres to hypothalamus
and thalamus
Superior cerebellar pedunc

41. Middle cerebellar peduncle
Pontocerebellar fibres
Inferior cerebellar peduncle
A. Fibres entering cerebellum
1. Posterior spino cerebellar tract
2. Cuneo-cerebellar tract
3. Olivo-cerebellar fibres
4. Reticulo-cerebellar fibres
5. Vestibulo-cerebellar fibres
6. Anterior external arcuate fibres
7. Fibres of striae medullaries
8. Trigemino-cerebellar fibres
B. Fibres Leaving the cerebellum
1. Cerebello-olivary fibres
2. Cerebello-vestibular fibres
3. Cerebello spinal and cerebello reticular
fibres
Middle cerebellar pedunc
Inferior cerebellar peduncle

42. Functions
• Regulates posture and postural activities
• Muscular co-ordination and balance
• Detection and correction of motor output from
cortex
• Controls timing of motor activities
• Maintenance of body posture,equlibrium and
eye movements.
• cerebellum may also have non-motor functions
such as cognition (acquisition of knowledge)
and language processing.

43. • Damage to the cerebellum can result in a
loss of ability to coordinate muscular
movements, a condition called ataxia .
• Cerebellar syndrome : muscular hypertonia,
intensional tremors, nystagmus, unsteady
gait etc.

44. Balance

45. Motor skills

46. BLOOD SUPPLY OF BRAIN
• Internal Carotid Artery:-
– Ant. cerebral artery
– Middle cerebral artery
• Vertebral Artery
– Anterior spinal artery
– Posterior spinal artery
– Posterior and inferior cerebellar artery
– Medullary artery
– Meningial branches

47. Basilar artery branches
• Superior, Inferior & anterior cerebellar
artery
• Pontine branches
• Labyrinthine artery

51. Circle of Willis
• The circle of Willis (also called Willis'
circle, loop of Willis, cerebral arterial circle,
and Willis polygon) is a circulatory
anastomosis that supplies blood to
the brain and surrounding structures.

52.  The circle of Willis is a part of the cerebral circulation and
is composed of the following arteries
 Anterior cerebral artery (left and right) forms
anterolateral part
 Anterior communicating artery-which connects right and
left Anterior cerebral artery and forms the anterior part.
 Internal carotid artery (left and right)-lateral part
 Posterior cerebral artery (left and right)
 Posterior communicating artery (left and right) – gives the
link between internal carotid and posterior cerebaral
 Circle completed at the bifurcation of basilar artery
 The middle cerebral arteries, supplying the brain, are not
considered part of the circle,

53. Functional Importance
• Equalizes the pressure of the blood flow to
the two sides of brain.
• The arterial anastamosis provides an
alternative route

54. Applied anatomy
Berry Aneurysm
• Localized dilatation on one of the arteries
of circle of Willis due to congenital
muscular weakness.

55. Venous drainage
• Cerebral veins and finally drain in to dural
venous sinuses

56. Ataxia: incoordination of
movement
- decomposition of movement
- dysmetria, past-pointing
- dysdiadochokinesia
- rebound phenomenon of
Holmes
- gait ataxia, truncal ataxia,
titubation
Intention Tremor
Hypotonia, Nystagmus
Archicerebellar Lesion:
medulloblastoma
Paleocerebellar Lesion: gait
disturbance
Neocerebellar Lesion: hypotonia,
ataxia, tremor
Syndromes

57. Cerebellar Ataxia
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

58. Cerebellar Medulloblastoma
Cerebellar tumors on vermis
- Truncal Ataxia
- Frequent Falling

59. THANK YOU