Cerebellum Structure and Function

Cerebellum Definition An organ concerned with the coordination of the voluntary movements It maintains posture and balance Situation Behind pons varolii Below the posterior portion of cerebrum In the posterior cranial fossa

Structure Ovoid in shape Two hemispheres Seaparated by vermis a median strip of tissue Grey matter forms the surface White matter in depth Cerebellum communicates with other regionof the CNS through three large nerve tracts called the cerebellar peduncles The cerebellum consists of following three parts

PARTS CONTROL flocculonodular Balance and maintenance of muscle tone Vermis – anterior part Motor coordination and muscle tone Vermis – posterior part and lateral hemispheres Fine motor coordination and muscle tone

Funtions Coordination of groups of voluntary muscles so that movements are smooth, even and precise Maintenance of body posture Coordination of activities associated with the maintenance of the balance and equilibrium of body. Cerebellar activities are carried out below the level of consciousnes i.e. not under voluntary control

Sensory input for cerebellum Derived from Muscles and joints Eyes Ears (from semicircular canals)

Applied anatomy Cerebellar dysfunction may cause Decreased muscle tone, Imbalance and Lack of co-ordination

Lobules of vermis and brain stem anatomy 1.Lingula 2. central lobule 3. culmen 4. declive 5. folium 6. tuber 7. pyramis 8. uvula 9. nodulus A. midbrain B.pons C. medulla D. cerebral aqueduct E. fourth ventricle F. primary fissure G. posterolateral fissure