Cerebellum Overview and Structure

Cerebellum Overview

• Metencephalic derivative located in the posterior cranial fossa.
• Positioned posterior to the pons and medulla, inferior to the tentorium cerebelli.
• Key functions include coordination of voluntary movements, maintenance of balance, equilibrium, and posture.

External Features

• Superior surface is convex.
• Inferior surface features a deep median notch known as the vallecula.

Structural Composition

• Comprises 2 hemispheres connected by the midline vermis.
• Can be categorized into anatomical lobes, zones, and functional lobes.
• Each hemisphere contains three anatomical lobes:
  • Anterior lobe: Superior surface, anterior to the primary fissure.
  • Posterior lobe: Extends from the primary fissure to the posterolateral fissure on the inferior surface.

Internal Structure

• Flocculonodular lobe consists of:
  • Outer layer of grey matter (cerebellar cortex).
  • Inner layer of white matter along with four nuclei.

Functional Parts

• Archicerebellum: The oldest part, responsible primarily for balance and equilibrium.
• Paleocerebellum: Functions in muscle tone and posture.
• Neocerebellum: Comprises most of the cerebellar hemispheres, coordinating voluntary movements.

Cerebellar Vasculature

• Blood supply derived from three pairs of arteries:
  • Superior cerebellar arteries (from the basilar artery).
  • Anterior inferior cerebellar arteries.
  • Posterior inferior cerebellar arteries (from the vertebral artery).
• Venous drainage occurs through superior and inferior cerebellar veins into dural venous sinuses via superior petrosal, transverse, and straight sinuses.