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Topic

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Cerebellum

The cerebellum is a major structure of the hindbrain located posterior to the brainstem and beneath the occipital lobes of the cerebral cortex. It plays a critical role in motor control, coordination, precision, and accurate timing of movements, as well as in maintaining balance and posture. Although it does not initiate movement, the cerebellum contributes to coordination, smoothness, and regulation of voluntary muscular activity. In addition, it is increasingly recognized for its roles in cognitive functions and emotional regulation.

Synonyms

  • Little brain

  • Metencephalon (developmental term)

Anatomy

  • Comprises two cerebellar hemispheres joined by a midline structure called the vermis.

  • Surface has many narrow, leaf-like folds called folia.

  • Divided into three anatomical lobes: anterior lobe, posterior lobe, and flocculonodular lobe.

  • Consists of a cortex (gray matter), underlying white matter, and deep cerebellar nuclei (dentate, emboliform, globose, fastigial).

  • Lies within the posterior cranial fossa, separated from the cerebrum by the tentorium cerebelli.

  • The cerebellum is connected to the brainstem via three cerebellar peduncles (superior, middle, inferior).

Arterial Supply

  • Superior cerebellar artery (SCA): Supplies the superior aspect.

  • Anterior inferior cerebellar artery (AICA): Supplies the anteroinferior portion.

  • Posterior inferior cerebellar artery (PICA): Supplies the posteroinferior part.

  • These arteries are branches of the vertebrobasilar system.

Venous Supply

  • Drained by the superior cerebellar veins (drain into the straight, transverse, and superior petrosal sinuses).

  • Inferior cerebellar veins (drain into the transverse, straight, and occipital sinuses).

  • Ultimately, venous drainage is via the dural venous sinuses to the internal jugular vein.

Function

  • Coordination of voluntary movements: Ensures smooth, balanced muscular activity.

  • Balance and posture: Regulates equilibrium and orientation.

  • Motor learning: Plays a role in acquiring and fine-tuning motor skills.

  • Cognitive functions: Involved in attention, language, and some aspects of emotional regulation.

  • Timing and rhythm: Important for the timing of muscle contractions and rapid, alternating movements.

MRI Appearance

  • T1-weighted images: Cerebellar cortex appears as low-to-intermediate signal; white matter is relatively hyperintense.

  • T2-weighted images: Cortex is hyperintense relative to white matter; folia are clearly seen.

  • FLAIR: Highlights edema, infarction, or demyelination.

  • Pathology: Atrophy seen as widened cerebellar sulci and folia; infarcts, tumors, and demyelinating lesions can be visualized.

  • Normal anatomical landmarks: “Arbor vitae” pattern (tree-like white matter branching) is visible.

CT Appearance

  • Gray matter: Slightly denser (hyperdense) compared to white matter, but difference is subtle.

  • White matter: Appears as lower density (“arbor vitae” can sometimes be seen in high-quality scans).

  • Pathology: Hemorrhage (hyperdense), infarcts (hypodense), mass effect, and calcifications can be assessed.

  • Atrophy: Seen as enlargement of the cerebellar sulci and cisterns.

  • Acute events: Edema or hemorrhage are more readily detected.

MRI images

Cerebellum MRI 3T coronal image

MRI images

Cerebellum MRI 3T sagittal image

CT image

Cerebellum CT image