Cerebellum

The cerebellum, meaning "the little brain"sits at the base of the brain in the posterior cranial fossa below the tentorium and behind the brainstem

The cerebellum has the following features:

  • three surfaces: anterior (petrosal), superior (tentorial), inferior (suboccipital)
  • three fissures: primary (tentorial), horizontal (petrosal), prebiventral/prepyramidal (suboccipital)
  • two hemispheres
  • single median vermis
Vermis

The vermis is divided into nine lobules: (in a clockwise rotation, looking at the patient sagittally from his left), and separated into groups by fissures:

  • lingula
  • central lobule
  • culmen: primary (tentorial) fissure
  • declive
  • folium: horizontal (petrosal) fissure
  • tuber: prebiventral/prepyramidal (suboccipital) fissure
  • pyramid
  • uvula
  • nodulus

The subdivisions of the cerebellar vermis can be remembered by this mnemonic.

Cerebellar hemisphere

The cerebellar folia run parallel to the calvaria in an onion-like configuration.

Each of the nine vermis lobules is associated in both sides with two cerebellar hemisphere lobules and therefore the cerebellum has 18 cerebellar hemisphere lobules:

  • wing of lingula (lingula)
  • wing of central lobule (central lobule)
  • quadrangular lobule (culmen): primary (tentorial) fissure
  • simple lobule (declive)
  • superior semilunar lobule (folium): horizontal (petrosal) fissure
  • inferior semilunar lobule (tuber): prebiventral/prepyramidal (suboccipital) fissure
  • biventral lobule (pyramid)
  • tonsil (uvula)
  • flocculus (nodulus)
Connections to brainstem
  • to midbrain: superior cerebellar peduncles (brachia conjunctiva)
  • to pons: middle cerebellar peduncles (brachia pontis)
  • to medulla: inferior cerebellar peduncles (restiform bodies)

The cerebellum is essentially supplied by three vessels:

  1. superior cerebellar artery (SCA): branch of the distal basilar
  2. anterior inferior cerebellar (AICA): branch of the proximal basilar
  3. posterior inferior cerebellar (PICA): branch of the distal vertebrals
Superior cerebellar (SCA)

The SCA supplies:

  • whole superior surface of the cerebellar hemispheres down to the great horizontal fissure
  • the superior vermis
  • dentate nucleus
  • most of the cerebellar white matter
Anterior inferior cerebellar (AICA)

The amount of tissue supplied by the AICA is variable (PICA-AICA dominance) but usually includes:

  • middle cerebellar peduncle
  • inferolateral portion of the pons
  • flocculus
  • anteroinferior surface of the cerebellum
Posterior inferior cerebellar (PICA)

The PICA has a variable territory depending on the size of the AICA, but usually supplies:

  • posteroinferior cerebellar hemispheres (up to the great horizontal fissure)
  • inferior portion of the vermis

There are some variations in the PICA:

  • 18% arise extracranially, inferior to the foramen magnum
  • 10% arise from the basilar rather than vertebral artery
  • 2% bilaterally absent
  • occasionally loops around the cerebellar tonsil
  • occasionally a small vertebral artery will terminate into a common PICA/AICA trunk

It divides into lateral and medial branches that supply the inferior portion of the vermis and cerebellar hemispheres respectively.


Neuroanatomy
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Article Information

rID: 891
Section: Anatomy
Synonyms or Alternate Spellings:
  • Anatomy of the cerebellum
  • Cerebellum anatomy
  • Cerebellar anatomy

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Cases and Figures

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    Figure 1: vascular territories
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    Figure 2: superior cerebellum
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    Figure 3: mid-cerebellum
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    Figure 4: Inferior cerebellum
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