Neuroanatomy: Cerebellum

Cerebellum

• Located in the posterior cranial fossa, superiorly separated from the cerebral hemisphere by the tentorium cerebelli
• Anteriorly, it is related to the back of the pons and medulla with the 4th ventricle

Gross Features of the Cerebellum

• Consists of two cerebellar hemispheres (large lateral parts formed of many gyri called folia) and a narrow median part called vermis
• Vermis is divided into superior and inferior vermis

Notches of the Cerebellum

• Anterior notch: a wide notch related to the back of the brain stem
• Posterior notch: a narrow notch which receives the falx cerebelli

Fissures of the Cerebellum

• Primary fissure: on the superior surface at the junction of the anterior one-third and posterior two-thirds
• Posterolateral fissure: on the inferior surface
• Horizontal fissure: between superior and inferior surfaces

Anatomical Classification of Lobes

• Anterior lobe: area on the superior surface cranial to the primary fissure
• Posterior lobe: area between primary and posterior fissures, lies in superior and inferior surfaces
• Flocculo-nodular lobe: lies in the inferior surface, consists of right & left flocculi and a median nodule

Cerebellar Peduncles

• Three peduncles connect the cerebellum with the brainstem:
• Superior cerebellar peduncles: connect cerebellum to midbrain
• Middle cerebellar peduncles: connect cerebellum to pons
• Inferior cerebellar peduncles: connect cerebellum to medulla oblongata

Structure of the Cerebellum

• Outer layer of grey matter: cerebellar cortex
• White matter: medullary center
• Four deep cerebellar nuclei:
• Fastigial nucleus
• Globose nucleus
• Emboliform nucleus
• Dentate nucleus

Divisions of the Cerebellum

• Longitudinal divisions: 3 zones
• Vermal zone: contains fastigial nuclei
• Paravermal zone: contains globose and emboliform nuclei
• Lateral zone: contains dentate nucleus
• Functional divisions:
• Archicerebellum (flocculo-nodular lobe): connected with the vestibular system, concerned with equilibrium
• Paleocerebellum (vermal and paravermal zones): connected with the spinal cord, concerned with regulation of muscle tone and muscle coordination
• Neocerebellum (lateral zone): connected with the cerebral cortex, concerned with planning and automatic control of movements

Signs of Cerebellar Dysfunction

• Intention tremor: involuntary, rhythmical wavering movement of the hand
• Loss of muscle coordination:
• Ataxia: the patient walks with legs far apart
• Nystagmus: the eyes make repetitive, uncontrolled movements
• Scanning speech: the speech is slurred and hesitating
• Dysmetria with overshooting: inability to measure the distance, results in overshooting the target

Learn about the cerebellum, a large posterior part of the brain, its location and general relations. Quiz covers the anatomy and structure of the cerebellum.