The document describes the anatomy and functions of the cerebellum. It discusses the gross features, subdivisions, internal structure including layers of the cerebellar cortex and nuclei, connections via afferent and efferent fibers, and clinical implications of cerebellar diseases. The cerebellum coordinates movement and maintains posture and balance through connections with other parts of the brain and spinal cord. Damage can result in motor disturbances like ataxia and intention tremors.

1. Cerebellum
Dr Muhammad Arshad
CIMS Multan

2. Learning Objectives
• At the end of demonstration, the student will
be able to:
• Describe the gross features of cerebellum
• Enumerate the deep nuclei and connections
• Describe the subdivisions of cerebellum
• Describe the cerebellar peduncles
• Explain the anatomical basis of clinical
features of cerebellar diseases

3. Introduction
• Develops from alar plates (rhombic lips) of the
metencephalon
• Cerebellum lies in posterior cranial fossa
behind pons and medulla oblongata
• Separated from pons and medulla by 4th
ventrical
• Weight: 150 gram

4. Introduction
• Cerebellum is separated from cerebrum by
tentorium cerebelli
• Its surface is marked by folia and fissures
• Cerebellum consists of two hemispheres
united in midline by the vermis
• Each hemisphere is connected to three parts
of brainstem by three pairs of fibers called
cerebellar peduncles

8. Functions
• The basic functions of cerebellum are
• 1. Maintenance of equilibrium
• 2. Regulation of muscle tone and learning of
repeated motor functions
• 3. Coordination of voluntary motor activity

9. Introduction
• Cerebellar disease is manifested by motor
disturbances, including staggering gait,
hypotonia , failure of coordination
• Note:- There is no paralysis or inability to
start or stop movement by cerebellar lesion

10. Major subdivisions of cerebellum
• Consists of a midline vermis and two lateral
hemisphere
• Covered by outer three-layered cortex, which
contains folia and fissures
• Contains a central medullay core, wich is the
white mater that contains myeliated axons
• And four cerebellar nuclei (dentate,
emboliform, globose and fastigeal nuclei)

12. Major subdivisions
• Interposed nucleus=(emboliform+globose
nuclei)

13. Nuclear connections of cerebellum

15. External Features
• Three parts: A part lying near the midline is
called vermis and two lateral hemispheres.
Two surfaces, three well marked fissures,
two notches.

16. External Features
• Surfaces: Superior and Inferior; Superior
surface is convex , no line of distinction
between vermis and hemispheres
• Inferior surface: on this aspect, two
hemispheres are separated by a deep
depression called vallecua. The vermis lies in
depth of this depression

17. Notches
• The anterior aspect of cerebellum is marked
by a wide shallow anterior cerebellar notch
which accommodates pons and medulla
• The posterior cerebellar notch is deep and
narrow, and lodges the falx cereblli

18. Fissures and Lobes
• The surface of cerebellum is marked by series
of fissures transversely.
• Some of the fissures are deeper than others.
They divide the cerebellum into lobes within
which smaller lobules may be recognized
• V-shaped Fissura prima running transveresly
across the superior surface

19. Fissures
• Posterolateral fissure seen on inferior surface
and separates flocculonodular lobe from rest
of cerebellum
• The horizontal fissure is most conspicuous
and runs along the lateral and posterior
margins of cerebellum
• It divides cerebellum into superior and
inferior surfaces

20. Lobes of cerebellum
Lobes:
• 1. The part anterior to primary fissure is
anterior lobe. (spinocerebellum) receives
inputs from muscle spindles and golgi tendon
organs via spinocerebellar tracts
• Play a role in regulation of muscle tone
• 2. Paleocerebellum consists of anterior(except
lingula)+pyramid+uvula of posterior lob

21. Lobes of cerebellum
• The part between primary and posterolateral
fissures is posterior (middle) lobe receives
input from neocortex via
corticopontocerebellar fibers
• Plays a role in coordination of voluntary motor
activity
• 3. Neocerebellum consists of posterior lobe
except pyramid and uvula

22. Flocculonodular lobe
• 4. Flocculonodular lobe
(vestibulocerebellum) is smallest of all and
lies on inferior surface in front of
posterolateral fissure
• Receives input from the vestibular system
• Plays a role in the maintenance of posture and
balance

23. Vermis
• Proceeding from above downwards, it consists
of the lingula, central lobule, and culman,(in
the anterior lobe); the declive, pyramid and
uvula (in the middle lobe); and the nodule (in
the flocculonodular lobe)

26. Subdivisions (lobules)

29. Internal structure
• Cerebellum is made up of a thin layer of grey
mater, cerebellar cortex and intracerebellar
nuclei
• A central core of white mater being arranged
in the form of branching pattern of a tree, is
called arbor vitae= tree of life
• The cerebellar cortex has a uniform srtucture
in all parts of cerebellum

30. Structure of cerebellar cortex
• It consists of three distinct layers with five
neurons:
• 1. Outer Molecular layer (outer Stellate
cells+Basket cells)
• 2. Intermediate Purkinje cell layer (Purkinje
cells)
• 3. Inner Granular layer (Granule cells+Golgi
cells )

32. Cerebellar cortex

33. Intracerebellar nuclei
• Embedded in the central core of white mater,
there are masses of grey mater which
constitute the cerebellar nuclei
• From lateral to medial these are
• 1. Dentate nucleus
• 2. Emboliform nucleus
• 3. Globose nucleus
• 4. Fastigial nucleus

34. Afferent fibers entering cerebellar
cortex
• Two different types:
• Mossy fibers: All fibers(excitatory) entering
cerebellum, other than olivocerebellar, end as
mossy fibers.
• These fibers originate from vestibular nuclei
(vestibulocerebellar), pontine nuclei
(pontocerebellar) and spinal cord
(spinocerebellar)

35. Cerebellar cortex layers,fibers and cells

36. Afferent fibers
• These fibers terminate in granular layer of
cortex within the glomeruli and excite granule
cells.
• Climbing fibers: Afferent excitatory fibers of
the olivocerebellar tract
• Terminate on dendrites of purkinje cells

37. Efferent fibers
• These are axons of Purkinje cells which
terminate in the cerebellar nuclei.
• These are inhibitory to cerebellar nuclei

38. Cerebellar Peduncles
• Superior -→ Midbrain ║Brain
• Middle - →Pons ║ Stem
• Inferior – →Medulla oblongata║

39. Fibers in cerebellar Peduncles
Superior Cerebellar
peduncle
Afferent Efferent
Mainly efferent Anterior spinocerebellar
Tectocerebellar
Cerebello-rubral
Dentato-thalamic
Dentato-olivary
Fastigio-reticular
Middle Cerebellar
peduncle
Only afferent
Cortico-ponto-cerebellar

40. Fibers in cerebellar peduncles
Inferior Cerebellar
peduncle
Mainly afferent
Afferent Efferent
Posterior spinocerebellar Cerebello-vestibular
Cuneo-cerebellar
(posterior external arcuate
fibers)
Cerebello-olivary
Olivo-cerebellar Cerebello-reticular
Para-olivo-cerebellar
Reticulo-cerebellar
Vestibulo-cerebellar
Anterior external arcuate
fibers
Stria Medullaris
Trigemino-cerebellar

41. Clinical correlation
• Hypotonia
• Disequilibrium
• Dyssynergia includes
• 1. Dysarthria
• 2. Dystaxia
• 3. Intention tremors
• 4. dysmetria (past-pointing)

42. Clinical correlation
• 5. Dysdiadochokinesia
• 6. Nystagmus
• 7. Asthenia
• Tumors of the cerebellam
• Astrocytomas
• Medduloblastomas
• Ependymomas

43. Clinical correlation

44. Clinical correlation