The document discusses the anatomy and connections of the cerebellum. It notes that the cerebellum is located posterior to the pons and medulla and is separated from the cerebrum by the tentorium cerebelli. It has three lobes - the anterior, middle, and flocculonodular lobes - which are divided by fissures. The cerebellum receives input from the spinal cord, vestibular system, and cerebral cortex and is involved in motor coordination and balance. Lesions of the cerebellum can cause ataxia, which is why physiotherapists play an important role in rehabilitation through exercises to improve posture and coordination.

1. cerebellum

2. •From a clinical point of view most of the connections
of cerebellum are with spinal cord and the cerebral
cortex
•The general functions of cerebellum are
maintenance of body equilibrium ,maintenance of
muscle tone and control of fine voluntary movements
and we also know that cerebellum has connections
with the vestibular nuclei. But it doesn’t initiate any movements
•So lesion to the cerebellum will lead to ATAXIA.
•Here comes the role of physiotherapists ,as the
patient will need exercises to maintain body postures
and equilibrium .
•Not that the ataxia can be totally cured by
Why do we need to know about cerebellum as physiotherapists?

3. SITUATION: Posterior cranial fossa,behind the pons and medulla.
HOW IS IT SEPERATED FROM CEREBRUM:By a fold of dura matter which is called the
TENTORIUM CEREBELLI. Anteriorly,the fourth ventricle intervenes between the
cerebellum and pons and medulla.
RELATIONS:
Anteriorly: fourth ventricle{part of the cavity of the ventricle extends into cerebelum
as a transverse cleft} ,pons ,medulla.
Posterioinferiorly: squamous occipital bone.
Superiorly: tentorium ceribelli.
SUBDIVISIONS OF CEREBELLUM:
*The cerebellum consists of a part lying near the midline called the vermis,and two
lateral cerebellar hemispheres.
*It has two surfaces – superior and inferior.
*On superior aspect no line of distinction but on the inferior aspect a deep
depression called vallecula is present ,and also the vermis is present in this vallecula
on the inferior aspect.
The vermis is seperated from the cerebellar hemispheres by a paramedian sulcus.

4. •The vermis is subdivided into 9 subdivisions – each has a lateral extension{except
lingula}
•The surface of the cerebellum is marked by a series of fissures that run more or
less parallel to each other,the fissures subdivide the surface of cerebellum into
narrow leaf like bands also known as folia.
•The long axis of these fissures are more or less transverse,when cut in right angles
to these fissures the structure appears like a tree ,hence named ArBOR VITAE (tree of
life).
•Some of the fissures are deeper than the others and these fissures are responsible
for the division of cerebellum into lobes.
•The horizontal fissure separates the superior and inferior surfaces.
• Fissura prima separates its respective lobe on superior surface.
•Postereolateral fissure separates its respective love on inferior surface.
FISSURES AND LOBES :
Gross anatomical structure of the cerebellum:
fissures lobes
Fissura prima Anterior lobe
Horizontal fissure Middle or posterior lobe
Posterolateral fissure Flocculonodular lobe

6. From developmental ,phylogentical and functional point of veiw the cerebellum is
often divided into:
These correspond roughly not precisely to
DEVELOPMENTAL DIVISION AND ITS RELATION WITH LOBES AND THEIR EXACT
FUNCTION:
Division Lobe Function
Archicerebellum{oldest part of
evolution found in aquatic
vertebrates}
Flocculonodular lobe and
lingula of vermis
Connected to vestibular part ,maintains
equilibrium of the body
Paleocerebellum{found after
archicerebellum in terrestrial
vertebrates with limbs}
Anterior lobe and pyramid and
uvula of vermis
Connected to spinal cord and maintains
muscle tone and fine control of crude
movements of limbs
Neocerebellum{newest part of
cerebellum and also the largest
part of cerebellum}
Middle lobe Extensive connections with cerebral
cortex,fine control -co ordination of
voluntary movements

8. Cerebellum has outer grey matter and inner white matter .
* OUTER GREY MATTER CONSISTS:
1.Dentate nucleus
2.Emboliform nucleus.
3.Globose nucleus .
4.Fastigial nucleus
*INNER WHITE MATTER CONSISTS:
1.Afferent fibres entering the cerebellum from outside.
2.Projection fibres from the cerebellar cortex to the cerebellar
nuclei.
3.Association fibres interconnecting different arts of cerebellar
cortex.
4.Commisural fibres connecting the two cerebellar hemispheres.
5.Fibres from the cerebellar nuclie to the centres outside the cerebellum.
EXTERNAL HISTOLOGY OF CEREBELLUM :

9. The fibres entering or leaving the cerebellum pass through three thick bundles
called the cerebellar peduncles .They are as follows :
1.superior
2.middle
3.inferior .
* FORMATION:
SUPERIOR- axons growing out of the dentate nuclues.
MIDDLE-axons growing into cerebellum from pontine
nucleus.
INFERIOR-fibres growing into cerebellum from spinal
cord and medulla.{also called restiform
body ,fibres are responsible for formation of
juxtarestifrom body}
Cerebellar peduncles :

10. The cerebellar cortex has 3 layers-namely:
1.molecular layer {mostly superficial}
2.purkinje cell layer.{often described as a part of molecular layer}
3.granular layer.{rests on white matter}
The cells of the cerebellar cortex are of 6 main types :
1.purkinje cells { forming layer named after them}.- they mostly form only
efferents
2.granule cells{forming the granular layer} – spaces occupied by them are
called cerebellar islands
3.outer stellate cells
4.basket cells{lying in the molecular layer}
5.golgi cells{present in granular layer}
6.bursh cells {present in granular layer}
INTERNAL HISTOLOGY :

12. *The afferents are divided into two kinds
1.Mossy fibres: -` Many of these fibers arise from the pontine nuclei, as well as vestibular
nuclei and from the spinal cord
`These fibers form excitatory connections with the deep cerebellar nuclei and the granule cells.
`Mossy fibers form connections with the dendrites of granule cells. Golgi cells and mossy fibers
form ‘glomeruli’.
`They brach profusely within the granular layer ,each branch ends in a expanded terminal called a
rosette.
2.Climbing fibres:- `These fibers arise from the inferior olivary nucleus, and send collaterals to
the deep nuclei before entering the cerebellar cortex.
`These fibers will reach Purkinje cells, and will synapse over the proximal dendrites and cell
bodies.
`These fibers are responsible for signaling errors we make in our motor system.
AFFERENT: AND EFFERENTS:

13. •Afferent connections
Olivocerebellar: Fibers arise from the olivary nucleus and decussate to
reach the fibers of the opposite Raphe nucleus. From here they pass
onwards as internal arcuate fibers, through the inferior peduncle and to
the opposite cerebellar hemisphere.
Vestibulocerebellar: This is a pathway that joins the pontine
tegmentum to the cerebellar cortex.
Reticulocerebellar: These fibers originate at various levels of
the reticular formation and mainly terminate in the vermis (which lies in
the midline).
Corticopontocerebellar tract: This connects the premotor areas to the
contralateral cerebellar hemisphere via the pontocerebellar tract.
Trigeminocerebellar fibres: These ascend via the inferior cerebellar
peduncles and transmit proprioceptive information from the face, to

14. •Efferent connections
Cerebellovestibular tract: This is an output from the cerebellum to
the extensor muscles of the axial muscles which coordinate muscle tone
adjustment.
Cerebelloreticular tract: This tract sends information to the motor
circuits of the brain stems.
Corticonuclear tract: This connects the cerebral cortex to the
brainstem and is functions for the motor function of the oculomotor
nerve.
Cerebellothalamic tract: This arises from the superior cerebellar
peduncle, arises from the cerebellar nuclei and decussates to terminate
in the ventral anterior nucleus of the thalamus.

15. •The spinocerebellar pathways covey propiceptive and also few times exteroceptive
impulses.
•The connections between spinal cord and cerebellum are direct ,indirect and cerebello-spinal.
•The connections from direct are of the limbs.
•The connections from indirect pathway carry impulses from tissues of head to the cerebellum.
•The connections from the cerebello-spinal pathway influences the spinal cord .
THE CONNECTIONS ARE GIVEN BELOW :{tracts}
CONNECTIONS BETWEEN CEREBELLUM AND SPINAL CORD:
DIRECT PATHWAYS INDIRECT PATHWAYS CEREBELLO-SPINAL PATHWAYS
*ventral spinocerebellar *spino-olivo cerebellar *cerebello-rubro-spinal
*dorsal spinocerebellar *spino-reticulo cerebellar *cerebello-vestibulo-spinal
*rostral spinocerebellar *spino-vestibulo cerebellar *cerebello-reticulo spinal
*cuneocerebellar *spino -tecto cerebellar *cerebello-tecto spinal

16. The connections of cerebral cortex to the cerebelllum is through indirect pathways only
1.CORTICO-CEREBELLAR PATHWAYS:
*The cerebral cortex influences the cerebellum through centres in the brainstem through the
following pathways.
I. cortico-ponto-cerebellar pathways {complex}
II. cortico –olivo-ccerebellar
III. cortico-reticulo-cerebellar
IV. corticorubro cerebellar
V. cortico-tecto-cerebellar
VI. cortico-spino-cerebellar
2.CEREBELLO-CORTICAL PATHWAYS:
*Cerebellaar impulses reach the cerebral cortex through this pathway
I. cerebello-reticulo-thalamo-cortical pathway
CONNECTIONS WITH CEREBRAL CORTEX:

17. COMPARISION WITH CEREBRUM:
Features Cerebrum Cerebellum
Weight (approx) 1500g 150 g
Surface area double of cerebellum 50% of cerebral cortex
Structure Not uniform ,(sulci ,gyrus) Uniform
No” of lobes 4 3
No” of cortical layers 6 3
Location Forebrain hindbrain
Activity control Initiates movements Supports movements

18. Truncal ataxia : *flocculonodular lobe defect.
*inability to sit upright and/or stand
without support,most apparent in a
sitting position
Staggering gait : *anterior lobe defect .
*in co-ordination in lower limbs
*cant walk in a straight line
*seen in alcoholics
Defective speech :*middle lobe defect
*phonation is defective
*less co-ordination in muscles of lips,
tongue and palate
CLINICAL SIGNIFICANCE: