Cerebellum
Updates to Article Attributes
The cerebellum, meaning "the little brain", sits at the base of the brain in in the posterior cranial fossa below the tentorium and behind the brainstem.
Gross anatomy
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 the midbrain via the superior cerebellar peduncles (brachia conjunctiva)
- to the pons via the middle cerebellar peduncles (brachia pontis)
- to the medulla via the inferior cerebellar peduncles (restiform bodies)
CSF cisterns
- cerebellopontine angle cistern
- cisterna magna
- quadrigeminal
plate cistern superior cerebellarcistern
Blood supply
The cerebellum is essentially supplied by three bilateral vessels from the vertebrobasilar system:
- superior cerebellar artery (SCA): branch of the distal basilar
- anterior inferior cerebellar (AICA): branch of the proximal basilar
- 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
- superior cerebellar peduncle
- middle cerebellar peduncle
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
- middle cerebellar peduncle
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
- inferior cerebellar peduncle
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.
Variant anatomy
- cerebellar agenesis
- tonsillar ectopia: asymptomatic protrusion of the tonsils through the foramen magnum by no more than 3-5 mm
-<p>The <strong>cerebellum</strong>, meaning "the little brain"<em>, </em>sits at the base of the <a href="/articles/brain">brain</a> in the posterior cranial fossa below the <a href="/articles/tentorium-cerebelli">tentorium</a> and behind the <a href="/articles/brainstem">brainstem</a>. </p><h4>Gross anatomy</h4><p>The cerebellum has the following features:</p><ul>- +<p>The <strong>cerebellum</strong>, meaning "the little brain"<em>, </em>sits at the base of the brain in the <a href="/articles/posterior-cranial-fossa">posterior cranial fossa</a> below the <a href="/articles/tentorium-cerebelli">tentorium</a> and behind the <a href="/articles/brainstem">brainstem</a>. </p><h4>Gross anatomy</h4><p>The cerebellum has the following features:</p><ul>
-<li>to the <a href="/articles/midbrain">midbrain</a> via the <a title="Superior cerebellar peduncles" href="/articles/superior-cerebellar-peduncles">superior cerebellar peduncles</a> (brachia conjunctiva)</li>-<li>to the <a href="/articles/pons">pons</a> via the <a title="Middle cerebellar peduncles" href="/articles/middle-cerebellar-peduncles">middle cerebellar peduncles</a> (brachia pontis)</li>-<li>to the <a href="/articles/medulla-oblongata">medulla</a> via the <a title="Inferior cerebellar peduncles" href="/articles/inferior-cerebellar-peduncles">inferior cerebellar peduncles</a> (restiform bodies)</li>- +<li>to the <a href="/articles/midbrain">midbrain</a> via the <a href="/articles/superior-cerebellar-peduncles">superior cerebellar peduncles</a> (brachia conjunctiva)</li>
- +<li>to the <a href="/articles/pons">pons</a> via the <a href="/articles/middle-cerebellar-peduncles">middle cerebellar peduncles</a> (brachia pontis)</li>
- +<li>to the <a href="/articles/medulla-oblongata">medulla</a> via the <a href="/articles/inferior-cerebellar-peduncles">inferior cerebellar peduncles</a> (restiform bodies)</li>
-<li><a href="/articles/quadrigeminal-plate-cistern">quadrigeminal plate cistern</a></li>-<li><a href="/articles/superior-cerebellar-cistern">superior cerebellar cistern</a></li>- +<li><a href="/articles/quadrigeminal-cistern-1">quadrigeminal cistern</a></li>