Cerebellum

Cerebellum• Site: Posterior cranial fossa, behind pons &

medulla oblongata.

• 2 Surfaces: Superior & Inferior.

• 3 Parts:

* Vermis

- Superior: indistinct from sup. surface.

- Inferior: lodged in the vallecula.

Anatomy of the CerebellumAnatomy of the Cerebellum

• 2 symmetrical hemispheres connected medially by the Vermis

• Folia: Transversely oriented gyri

• Neural arrangement: Gray matter (Cortex), White matter (Internal),

• Scattered cerebellar nuclei: dentate, globose, emboliform, fastigial

Cerebellum• * 3 Lobes:• Anterior• Middle• floccculonodular• 3 Fissures:

* Primary

* Horizontal

* Posterolateral

Anterior lobe

Posterior lobe

Primary fissure

Functional Divisions:

* Paleo-cerebellum: spino-cerebellum. * Neo-cerebellum: cerebro-cerebellum. *Archi-cerebellum:vestibulo-cerebellum.

• Spinocerebellum : (Vermis + Intermed. Hem)

• Cerebrocerebellum : (Lateral hemisphere)

• Vestibulo-cerebellum : (Floculo-nodular lobe)

Neocerebellum

Archicerebellum

Paleocerebellum

Functions of cerebellum

Maintenance of EquilibriumMaintenance of Equilibrium• - balance, posture, eye movement - balance, posture, eye movement Coordination of half-automatic movement ofCoordination of half-automatic movement of• walking and posture maintenacewalking and posture maintenace• - posture, gait - posture, gait Adjustment of Muscle ToneAdjustment of Muscle Tone Motor Leaning – Motor SkillsMotor Leaning – Motor Skills Cognitive FunctionCognitive Function -- (attention and(attention and language)language)

• Ataxia ( is a neurological sign consisting of lack of voluntary coordination of muscle movements

• . Ataxia is a non-specific clinical manifestation implying dysfunction of the parts of the nervous system that coordinate movement, such as the cerebellum

The damage to cerebellum may lead to may problems in an individual. These problems affect the brain as follows:

Asynergia: This is loss of coordination of motor movement.Dysmetria: The person finds it difficult to judge distance and when to stop.Adiadochokinesia: This is a condition where the person is unable to perform rapid alternating movements.Intention tremor: The patient may tremor while carrying out certain movements.Ataxic gait: Staggering and swaying while walking.Hypotonia: A person develops weak muscles.Ataxic dysarthria: Development of slurred speech.Nystagmus: Abnormal eye movements.

Cerebellum Function Test

There are certain neurological tests carried out to check the functions of the cerebellum. The cerebellum function test carried out generally are as follows:

• Finger-to-nose.

• Alternating hand movements.

• Romberg test

• Gait test

• Vestibular exam

Romberg test

• ask the patient to stand, feet together with eyes closed and arms at sides

• Romberg-only positive if loss of balance occurs

• The Romberg test is used to investigate the cause

of loss of motor coordination (ataxia)

• . A positive Romberg test suggests that the ataxia is sensory in nature, that is, depending on loss of proprioception. If a patient is ataxic and Romberg's test is not positive, it suggests that ataxia is cerebellar in nature, that is, depending on localized cerebellar dysfunction instead.

FTN test (Finger-to-nose.)

• ask the patient to alternately point from his or her nose to the examiner’s finger

• the examiner will typically move his or her finger to different locations

HTS test (heel to shin)

• ask the patient to run the heel of one foot along the shin of the opposite leg

• the patient then does the same procedure on the opposite side