Cerebellum Anatomy Relevant to Dizziness

Timothy C. Hain, MD Marcello Cherchi, M.D., Ph.D. Page last modified: March 13, 2021

This page is meant to provide a general outline of cerebellar function. It is adapted from a clinical neuroanatomy lecture given on a yearly basis to Northwestern PT students. This page is "under construction" and should not be relied upon.

Normal axial MRI
The cerebellum with surrounding skull and spinal fluid occupies the bottom 1/3 of this axial MRI image.


What is the cerebellum and what does it do ?

The cerebellum is part of the brain. It lies under the cerebrum, towards the back, behind the brainstem and above the brainstem. The cerebellum is largely involved in "coordination". Persons whose cerebellum doesn't work well are generally clumsy and unsteady. They may look like they are drunk even when they are not.


Gross Anatomy:

Cerebellar Hemispheres and Vermis

cerebellar hemispheres



Gross Anatomy: Lobes & Lobules

Gross Anatomy: Fissures

Connections with brainstem:

cerebellar afferents

Afferent connections with spinal cord and brain


Cerebellar efferents
Cerebellar Efferents

Efferent connections


Sections of the Cerebellum

Vestibulocerebellum or archicerebellum

  • Comprises the flocculonodular lobe
  • Extensive connections with the vestibular system
  • Phylogenetically oldest

Spinocerebellum or paleocerebellum

  • Comprises the vermis (medial) & paravermal (intermediate) region
  • Extensive connections with the spinal cord & brainstem
  • Phylogenetically of intermediate age

Cerebrocerebellum or neocerebellum

  • Comprises lateral portions of cerebellar hemispheres (excluding paravermal regions)
  • Extensive connections with cerebral cortex through relay stations in cerebellar nuclei and dorsal thalamus
  • Phylogenetically youngest


Cerebellar pathways



Superior cerebellar peduncle (brachium conjunctivum)


Middle cerebellar peduncle (brachium pontis)

Inferior cerebellar peduncle (“corpus restiform” or “restiform body”)

Connects to medulla

Cerebellar Nuclei

cerebellar nuclei fastigial bleed


Cerebellar bleed into fastigial area. (MRI image is flipped to match anatomical orientation on left)

The patient associated with the right image above had a bleed into the area of her fastigial nucleus, blood filling her 4th ventricle, 3rd ventricle, and in ther lateral ventricles. This was decompressed surgically. From the picture above, certainly there could also be damage to several other deep cerebellar nuclei as well. Seven years later, she still had exotropia, inability to converge, horizontal saccadic dysmetria, some dysarthria, and gait ataxia. She had no spontaneous or positional nystagmus at all.

A movie of her eye is shown here. Note how the eye overshoots several times after returning to center.

Fastigial nucleus

  • Controls antigravity muscles
  • Controls proximal muscles of stance (station) & walking (ambulation)
  • Controls eye movements (lesions create overshoot dysmetria, exophoria).


Globose and emboliform (the “interposed nuclei”)

Dentate nucleus

The Dentate nucleus is part of the "triangle of Guillain Molleret" which is involved in oculopalatal myoclonus.

The triangle of Guillain-Mollaret -- Source: https://www.mni.mcgill.ca/neuroimage/


Another schematic of the triangle of Guillain-Mollaret -- source: https://www.neurology.org/cgi/content/full/71/4/301/F119. This view is a coronal view mainly showing the brainstem.


Vestibular nucleus


cortical layers layer circuits






Cortical Layers

Histology: Cell Types

Purkinje Cells

Largest cells in CNS (cell body = 60-90 µm in diameter)

Cell body

  • In Purkinje cell layer
  • Inhibitory synapse (GABA) from basket cells
  • Excitatory synapse (aspartate) from a single climbing fiber


  • In molecular layer
  • Dendritic arbor is “planar,” oriented in a rostrocaudal plane
  • Inhibitory synapses (GABA & taurine) from stellate cells
  • Excitatory synapses (glutamate) from granule cells’ parallel fibers.  Over 200,000 mossy fibers indirectly (through Golgi cell, then granule cell) excite each Purkinje cell


  • The only projections that exit the cerebellar cortex
  • Mostly project to cerebellar nuclei (to all four); some fibers project to vestibular nuclei in brainstem
  • Forms inhibitory synapses (GABA)
  • Often also releases a peptide cotransmitter
layers 2


Granule Cells

granule cells



1 x 1011 granule cells (more neurons than entire cerebral cortex!)

Cell body

  • Located in granule cell layer
  • Inhibitory synapse (GABA) from Golgi cells


  • Projects from granule cell layer, through Purkinje cell layer, up to molecular layer, where it forms parallel fibers (which are oriented in a horizontal plane, parallel to the cerebellar folia)
  • Forms excitatory synapses (glutamate) on Golgi, basket and stellate cell

Golgi Cells

Basket Cells

Stellate Cells

Cerebellar Circuits

Mossy Fiber System

Climbing Fiber System

Monoaminergic Fiber System

The monoaminergic projections to cerebellum send fibers to all three layers of cerebellar cortex.

Projections include:


Cerebellar Arterial Vasculature

brainstem arteries

SCA (superior cerebellar artery)

AICA (anterior inferior cerebellar artery)

PICA (posterior inferior cerebellar artery)


Clinical Correlates of Cerebellar disease

Postural instability


Other Clinical Correlates




Errors in smoothness and direction of movement

Lack of coordination or synergy of movement (“decomposition” of complex movements)

Lack of motor plasticity or motor learning


  • Have patient hang forearm loosely from elbow and induce a passive swing (“pendulous reflex”)
  • Check tendon reflexes