Anatomy of the Cerebellum

Page 5: Cerebellum: Location

  • Posterior cranial fossa

  • Tentorium cerebelli

  • Fourth ventricle

Page 6: Cerebellum Functions

  1. Maintenance of equilibrium (balance)

  2. Coordination of voluntary movement

    • Provides precise timing and appropriate patterns of skeletal muscle contraction

  3. Control muscle tone and posture

  4. Learning & memory of motor tasks

Page 7, 8, 9: Cerebellum Connection with Brainstem

  • Cerebellum is connected to posterior brainstem

  • Attached to superior, middle & inferior cerebellar peduncle

Page 10: External Features

  • Cerebellum consists of 2 cerebellar hemispheres, joined in midline by vermis.

  • Surface displays alternating parallel elevations called folia and grooves known as sulci to increase surface area.

    • Vermis

    • Cerebellar hemisphere

    • Folia & sulcus

Page 13: Cerebellum Fissures

  1. Primary Fissure: V-shaped fissure separating the anterior and posterior lobes.

  2. Uvulonodular (posterolateral) Fissure: separating the flocculonodular lobe and the posterior lobe.

  3. Horizontal Fissure: margin separating the superior and inferior surfaces of the cerebellum.

Page 14: External Features

Page 18

Cerebellum: External Features

Page 19

  • Cerebellum has 3 lobes:

    1. Anterior lobe

    2. Posterior (middle) lobe

    3. Flocculonodular lobe (composed of left/right flocculi and nodulus)

  • Lobes can be further divided into lobules

Page 20

  • Cerebellum is composed of outer cortex (gray matter) and inner white matter

  • Embedded in white matter are deep cerebellar nuclei (also gray matter):

    1. Dentate (most lateral)

    2. Emboliform

    3. Globose

    4. Fastigial (most medial)

  • Emboliform & globose nuclei are collectively known as interposed nuclei

Page 21: Cerebellum Internal Features

Page 22: Deep Nuclei / Intracerebellar Nuclei

Page 23: Deep Nuclei/Intracerebellar Nuclei

  • Deep cerebellar nuclei are gray matter embedded deep in the white matter of the cerebellum

  • They are the main source of cerebellar output

Page 24: Deep Nuclei Input

  • Each cerebellar nucleus receives input from specific areas of cerebellar cortex:

    • Fastigial nucleus – receives input from the cortex of flocculonodular lobe and vermis

    • Globose & emboliform nuclei – receive input from the paravermal zone

    • Dentate nucleus – receives input from the lateral hemisphere of cerebellum

Page 25: Cerebellum Subdivisions

  1. Anatomic subdivision

    • Lobe subdivision

      • ant, post & flocculonodular lobes

    • Longitudinal zone

      • vermis, paravermis, lateral hemisphere.

  2. Functional area

    • Vestibulocerebellum, spinocerebellum, cerebrocerebellum

  3. Phylogenic subdivision

    • Archicerebellum, paleocerebellum, neocerebellum

Page 26: Longitudinal Zones

Cerebellum can be divided into 3 longitudinal zones (based on functional & connections)

  1. Vermis

  2. Paravermal zone (Intermediate zone) - medial strip of cerebellar hemisphere adjacent to vermis

  3. Lateral hemispheric zone - lateral part of cerebellar hemisphere

Page 27: Functional Areas

  1. Cerebrocerebellum

    • Corresponds to lateral zone of cerebellar hemisphere

  2. Spinocerebellum

    • Corresponds to vermis & paravermal zone

  3. Vestibulocerebellum

    • Corresponds to flocculonodular lobe

Page 28

Cerebrocerebellum:

  • The largest division, formed by the lateral hemispheres

  • Involved in planning movements and motor learning

  • Receives inputs from the cerebral cortex and pontine nuclei

  • Sends outputs to the thalamus and red nucleus

  • Regulates coordination of muscle activation and is important in visually guided movements.

Spinocerebellum:

  • Comprised of the vermis and intermediate zone of the cerebellar hemispheres

  • Involved in regulating body movements by allowing for error correction; also receives proprioceptive information.

Vestibulocerebellum:

  • Functional equivalent to the flocculonodular lobe

  • Involved in controlling balance and ocular reflexes

  • Receives inputs from the vestibular system

  • Sends outputs back to the vestibular nuclei

Page 29: Phylogenic (Evolutionary) Subdivision

  • The division of the cerebellum into three major parts or regions based on its evolutionary development helps understand how the cerebellum has evolved in different species to serve varied functions.

Page 31: Cerebellar White Matter

  • Arbor vitae is the white matter present in the cerebellum of the brain. It has a tree-shaped structure.

Page 32: Cerebellar White Matter

White matter fibres:

  1. Intrinsic

    • Connect different regions of the cerebellum.

  2. Afferent

    • Most abundant fibers.

    • Enter mainly through middle & inferior cerebellar peduncle.

    • Fibers are from cerebrum, spinal cord, and inner ear.

  3. Efferent

    • Output of the cerebellum

    • Axon of the Purkinje cells of the cerebellar cortex

    • Majority will synapse with deep cerebellar nuclei (DCN)

    • Fibers from DCN leave the cerebellum via superior cerebellar peduncle

Page 33: Corticopontocerebellar pathway

  1. Fibers from cerebral cortex

  2. Descend through corona radiata & internal capsule.

  3. Synapse with pontine nuclei

  4. Fibers from pontine nuclei (transverse fibers of the pons)

  5. Cross midline; enter opposite side of cerebellum via middle cerebellar peduncle.

Page 34: Cerebro-olivocerebellar pathway

  1. Fibers from cerebral cortex

  2. Descend through corona radiata & internal capsule.

  3. Synapse with olivary nuclei

  4. Fibers from olivary nuclei

  5. Cross midline; enter opposite side of cerebellum via inferior cerebellar peduncle.

Page 35: Cerebroreticulocerebellar pathway

  1. Fibers from cerebral cortex (sensorimotor area)

  2. Descend through corona radiata

  3. Synapse with Reticular formation

  4. Fibers from Reticular formation (reticulocerebellar fibres)

  5. Enter the same side of cerebellum via inferior & middle cerebellar peduncles.

Page 36: Cerebellar Afferent Fibers (from Spinal Cord)

  1. Anterior spinocerebellar tract: upper & lower limbs

  2. Posterior spinocerebellar tract: trunk & lower limbs

  3. Cuneocerebellar tract: upper limbs and upper thorax

All receive information from muscle spindle, joint, and tendon

Page 37: Cerebellar Afferent Fibers (from Inner Ear)


Vestibular nuclei receive information from inner ear ; concerning motion from the inner ear.

Page 38: Cerebellar Efferent Fibers

1. Purkinje Cell Axons:

  • Principal output neurons of the cerebellar cortex

  • Transmit processed information from the cerebellar cortex to other parts of the brain, primarily the deep cerebellar nuclei and vestibular nuclei

  • Modulate and coordinate motor commands, contributing to motor control and coordination.

2. Deep Cerebellar Nuclei Output:

  • Deep cerebellar nuclei, including fastigial, interposed, and dentate nuclei, serve as efferent fibers.

  • They receive input from Purkinje cells and project to various parts of the brain, including the thalamus and brainstem

  • Essential for transmitting refined motor commands and playing a key role in motor planning and execution.

Page 39: Blood Supply

  1. Superior Cerebellar artery, a branch of basilar artery

  2. Anterior Inferior Cerebellar artery, a branch of basilar artery

  3. Posterior Inferior Cerebellar artery, a branch of vertebral artery

Page 40

  • Each cerebellar hemisphere is connected by nervous pathways principally with the same side of the body

  • A lesion in one cerebellar hemisphere produces signs and symptoms limited to that same side of the body.

Page 41

  • Clinical Signs:

    • Dysdiadochokinesis - impairment in performing rapid alternating movements.

    • Ataxia - unsteady gait, difficulties with balance, and issues with fine motor skills.

    • Nystagmus - involuntary, rhythmic movement of the eyes.

    • Intention tremor

    • Scanning dysarthria - slow, monotonous speech.

    • Heel-shin test positivity – unable to produce smoothly and accurately moving their heel down their shin, typically due to a loss of coordination.