cerebellar hemisphere

The cerebellum consists of three parts that are continuous with one another and substantially the same in structure: a median portion and two lateral portions. The median part is constricted and called the vermis, a name drawn from the annulated appearance produced by the transverse ridges and furrows on it, while the expanded lateral portions are the hemispheres. The hemispheres are thus the paired regions lying outside and lateral to the central vermis. Among the cerebellar subdivisions the lateral hemisphere is considered the most recently developed in phylogenetic terms. Two subordinate structures are recorded beneath this entry, and the hemisphere is classified as a regional part of the cerebellar cortex within the nervous system.