Two longitudinal furrows, most prominent on the undersurface of the cerebellum's posterior lobe, identify the region of the vermis (Latin word for "worm"), a thin longitudinal strip in the midline, wich separates the left and right cerebellar hemispheres. The part of the hemisphere closest to the vermis is called the intermediate part; the remainder of the hemisphere is the lateral part. The vermis and the two parts of the hemisphere are connected to different deep nuclei and to different components of the descending systems and constitute funcionally distinc regions of the cerebellum. The vermis, through direct projections to the vestibular nuclei and through indirect projections to other medial brain stem and cortical descending systems, controls axial and proximal limb muscles.