Anatomy of the cerebellum a narrow midline zone called the "vermis". A set of large folds are conventionally used to divide the overall structure into ten smaller lobules. Because of its large number of tiny granule cells, the cerebellum contains more neurons than the rest of the brain put together, but it only takes up 10% of total brain volume. The cerebellum receives nearly 200 million input fibers; in contrast, the optic nerve is composed of a mere one million fibers. The unusual surface appearance of the cerebellum conceals the fact that the bulk of the structure is made up of a very tightly
Anatomy of the cerebellum the face; it can also cause hearing impairment. Moreover, it could cause an infarct of the cerebellopontine angle. This could lead to hyperacusia (dysfunction of the stapedius muscle, innervated by CN VII) and vertigo (wrong interpretation from the vestibular semi-circular canal's endolymph acceleration caused by alteration of CN VIII). The PICA branches off the lateral portion of the vertebral arteries just inferior to their junction with the basilar artery. Before reaching the inferior surface of the cerebellum, the PICA sends branches into the medulla, supplying blood to several cranial nerve nuclei. In the cerebellum, the PICA supplies blood to the