The cerebellum is part of the metencephalon and supervises the coordination and fine tuning of motion sequences.
The cerebellum is in the posterior cranial fossa and is divided from the cerebrum by the cerebellar tentorium. The falx cerebelli is between the two largely symmetric cerebellar hemispheres . The cerebellum borders on medulla oblongata and the pons and constitutes the roof of the 4th ventricle. The cerebellomedullary cistern is highly clinically significant, because it is where liquor can be extracted in case of a suboccipital puncture which is relevant for diagnostics.
The cerebellum is connected to the brainstem via the three cerebellar penduncles. The afferents mainly proceed in the middle cerebellar penduncleand inferior cerebellar penduncle, the efferents in the superior cerebellar penduncle. The two cerebellar hemispheres are divided into three main lobes by two fissures:
The primary fissure divides the anterior and posterior lobe, the posterolateral fissure divides the posterior from the flocculonodular lobe. The two hemispheres are divided by the cerebellar vermis. Lateral of the cerebellar vermis is the flocculus on both sides which is connected to the lower part of the vermis via the nodulus. Flocculus and nodulus constitute the flocculonodular lobe. The cerebellar tonsils are the most caudal structure of the cerebellum. They are directly above the foramen magnum. The surface of the cerebllum is interspersed with lots of bulges (cerebellar folia) and fissures, which both increase the surface.
