Anatomy (CNS) · MU Sofia

155. Cerebellum – body of cerebellum and internal features.

Covers the position of the cerebellum in the posterior fossa and its connections to the brainstem, then its external division into lobes and surfaces by fissures. Internal structure is taken in turn: the three cortical layers, the fastigial, dentate and interposed nuclei, and the three cerebellar peduncles. It closes with climbing and mossy fibre types and their synapses, and includes a mnemonic for the nuclei.

Inside: 4 sections · 6 labelled pictures · 10 flashcards · 3 min

Topic 13 of 34 in the MU Sofia syllabus for Anatomy (CNS) (Medicine, Year 2). The free AceMed note covers it in 4 sections, about 377 words (3 min of reading), with 10 flashcards.

In this note

  1. CEREBELLUM
  2. Topography:
  3. External features:
  4. Internal features:

Topography:

  • It is the largest part of the hindbrain.
  • It is present in the posterior cranial fossa, below the cerebral hemispheres, seperated from them by dural fold "tentorium cerebelli"
  • It lies posterior to pons and medulla oblongata with the 4th ventricle intervening.
  • It communicates with the brainstem through the cerebellar peduncles.
  • Function: regulation of muscle tone, maintaining equilibrium & posture, and coordination of voluntary movements.

There are 8 lobules within the vermis, the lobules of the cerebellar hemispheres generally correspond to the ones of the vermis:

Sup.

Inf.

External features:

  • It is formed of 2 cerebellar hemispheres connected by the vermis.
  • The surface of the cerebellum is indented by neumrous parallel fissures "folia cerebelli"

→ Anatomical division:

  • 3 lobes: Anterior, posterior & folocculonodular — seperated by the primary fissure; seperated by postrolateral fissure
  • 2 Surfaces: Superior & inferior seperated by the horizontal fissure.

→ Functional division

Internal features:

  1. 1. Cerebellar Cortex: is the outer layer
  • Plays a crucial role in motor coordination, balance, and motor learning.
  • Organized into distinct layers:
  • Molecular Layer (Outermost): Contains axon branches of granule cells & the dendrites of Purkinje cells. → Stellate cells + Basket
  • Purkinje cell layer: Receiving 2 types of afferent fibers (direct climbing: from olivary nuclei) and (indirect Mossy: the remaining afferent fibers after relay in granule cells).
  • 3. Granular layer: - the innermost layer. - Contains granular cells. + Golgi cells
  1. 2. Cerebellar nuclei
  • They are embedded within the white matter.
  • They are:
  1. 1. Fastigial nucleus; medially → flucculonodular lobe + virmes
  2. 2. Dentate nucleus; laterally → lateral hemisphere
  3. 3. Interposed nuclei; in between: globose & emboliform nuclei → vermal + paravirmal areas

" Don't Eat Gressy Food "

  1. 3. Cerebellar white matter:
  • Superior Cerebellar Peduncle: Primarily efferent fibers that project to the midbrain and thalamus.
  • Middle Cerebellar Peduncle: Contains afferent fibers from the pons (pontocerebellar fibers) that carry input from the cerebral cortex.
  • Inferior Cerebellar Peduncle: Contains both afferent and efferent fibers, connecting the cerebellum with the medulla and spinal cord.
  1. 4. Fiber types
  • Climbing Fibers: Originate from the inferior olivary nucleus and make powerful excitatory synapses with Purkinje cells.
  • Mossy Fibers: Originate from various sources including the spinal cord, pontine nuclei, and vestibular system. They synapse with granule cells in the granule cell layer, indirectly influencing Purkinje cells through parallel fibers.

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