4. External features of cerebellum
It consists of 2 hemispheres & a vermis connecting them.
Superiorly the cerebellar hemisphere shows primary fissure. The part ant to primary fissure is the ant lobe.
Inferiorly, the vermis shows secondary fissure. The part ant to secondary fissure is called nodule & is connected to a part of the hemispheres called floccule to form flocculonodular lobe.

5. The rest of the cerebellum is the post (middle) lobe, including a horizontal fissure between sup & inf surfaces.
Inferiorly, part of the hemisphere projects through foramen magnum called tonsils.
The cerebellum shows outer grey matter lobules called folia. It has an inner tree shaped white matter called arbor vitae.

6. Functional lobes of cerebellum
Output
Input
Function
Corresponding anatomical lobe & nuclei
Functional lobe
Project to spinal cord to maintain balance
Information from inner ear
Equilibrium
Flocculonodular lobe
(fastigial nucleus)
Vestibulocerebellum (archicerebellum)
Projects to spinal cord (AHCs) to control muscle tone
Unconscious proprioception from the same side of body through spinocerebellar tracts & same side of head & neck through spinotrigeminal tracts
Regulate muscle tone
Vermal & paravermal zones of ant & post lobes
(fastigial & interposed nuclei)
Spinocerebellum (paleocerebellum)
Projects back to cerebral cortex which projects to spinal cord
Motor & sensory information from cerebral cortex
Planning & control of movements
Lat zone of ant & post lobes
(dentate nucleus)
Cerebrocerebellum (neocerebellum)

7. Applied anatomy: cerebellar dysfunction: Ataxia (incoordinated movements), nystagmus (incoordination of eye muscles), Scanning speech (incoordination of speech muscles), intension tremors (only during movement), dysmetria (disturbed movement distance) & dysdiadochokinesia (inability to perform 2 opposite quick movements)