cerebellum

cerebellum

1. occupies most of the posterior cranial fossa.

2. The primary anatomical landmarks are the cerebellar hemispheres

   • the nodule
   • the flocculus
   • the tonsil
   • the vermis

3. Is intimately involved in maintaining balance and coordinanting fine motor control of muscles involved in voluntary movement.

4. Topography

   • The cerebellum is positioned inferior to the posterior portion of the cerebral hemispheres, it is separated from de cerebrum by the tentorium cerebelli.
   • Relative to the surface of the skull, the cerebellum is located deep to the occipital bone, where it fills the posterior cranial fossa.Together, the superior medullay vellum, inferior medullay vellum and superior cerebellar peduncles from the roof of the 40th ventricle, the cerebellum is posterior to the 4th ventricle.

5. Gross Structure

   • The cerebellum is most visibly devided into the 2 cerebral hemispheres. the 2 cerebellar hemispheres are separated by a fold of dura mater called the flax cerebelli, Though several cranial nerves appear around the surface of the cerebellum, the cerebellum does not originate any CN.
   • Structures
     • Inferior inspection of the cerebellum reveals the following structures
       • Vermis
         • Located along the midline of the cerebellum, connects the cerebellar hemispheres.
       • Nodule
         • Located along the inferior portion of the vermis, this lobules is framed by 2 tonsils
       • Tonsil
         • Paired rounded lobules that are visible when viewing the underside of each cerebellar himesphere.
       • Flocculus
         • Small lobe located along the posterior border of the middle cerebellar peduncle.
       • Flocculonodular lobe
         • Lobe formed when considering the nudule and the flocculus of the cerebellum together.
   • Connection to brainstern
     • the cerebellum is connected to the brainstern via 3 cerebellar peduncles.
       • Superior cerebellar peduncle
         • Connects the cerebellum to the thalamun in a motor pathway that terminates in the cortex, In addition, that pathways in the superior cerebellar peduncle serve as the principe pathways bringing information to the cerebellum.
       • Middle cerebellar peduncle
         • Connects the cerebellum to areas of motor cortex. These pathways are involved in movement.
       • Inferior cerebellar peduncle
         • Connects the cerebellum to the spinal cord, nuclei of vestibulocochlear verne and nuclei of the brainstern. these pathways are involved in the maintenance of equilibrium