Lateral Perspective of Cerebellar Hemisphere Lobules. The cerebellum is divided anatomically into the anterior, posterior, and flocculonodular lobes. The anterior and posterior lobes of the cerebellum are separated by the primary (preclival) fissure. The quadrangular lobule is divided into an anterior portion (in the anterior lobe) and posterior portion (in the posterior lobe) by the preclival fissure.  The superior posterior fissure divides the posterior quadrangular lobule (also referred to as the simple lobule) from the superior semilunar lobe. The superior semilunar lobule is separated from the inferior semilunar lobule by the horizontal fissure. The gracile lobule is separated from the inferior semilunar lobule by the inferior posterior fissure. The biventer lobule is then separated from the gracile lobule by the inferior anterior fissure. Lastly, the biventer lobule is separated from the cerebellar tonsil by the secondary fissure (not demonstrated). (Image courtesy of AL Rhoton, Jr.)