Henry Gray (18251861). Anatomy of the Human Body. 1918.
into its substance, and divide it into a series of layers or leaves. The largest and deepest fissure is named the horizontal sulcus. It commences in front of the pons, and passes horizontally around the free margin of the hemisphere to the middle line behind, and divides the cerebellum into an upper and a lower portion. Several secondary but deep fissures separate the cerebellum into lobes, and these are further subdivided by shallower sulci, which separate the individual folia or laminæ from each other. Sections across the laminæ show that the folia, though differing in appearance from the convolutions of the cerebrum, are analogous to them, inasmuch as they consist of central white substance covered by gray substance.
The cerebellum is connected to the cerebrum, pons, and medulla oblongata; to the cerebrum by the superior peduncle, to the pons by the middle peduncle, and to the medulla oblongata by the inferior peduncles.
The upper surface of the cerebellum(Fig. 702) is elevated in the middle and sloped toward the circumference, the hemispheres being connected together by the superior vermis, which assumes the form of a raised median ridge, most prominent in front, but not sharply defined from the hemispheres. The superior vermis is subdivided from before backward into the lingula, the lobulus centralis, the monticulus and the folium vermis, and each of these, with the exception of the lingula, is continuous with the corresponding parts of the hemispheresthe lobulus centralis with the alæ, the monticulus with the quadrangular lobules, and the folium vermis with the superior semilunar lobules.
The lingula (lingula cerebelli) is a small tongue-shaped process, consisting of four or five folia; it lies in front of the lobulus centralis, and is concealed by it. Anteriorly, it rests on the dorsal surface of the anterior medullary velum, and its white substance is continuous with that of the velum.
The Lobulus Centralis and Alæ.The lobulus centralis is a small square lobule, situated in the anterior cerebellar notch. It overlaps the lingula, from which it is separated by the precentral fissure; laterally, it extends along the upper and anterior part of each hemisphere, where it forms a wing-like prolongation, the ala lobuli centralis.
The Monticulus and Quadrangular Lobules.The monticulus is the largest part of the superior vermis. Anteriorly, it overlaps the lobulus centralis, from which it is separated by the postcentral fissure; laterally, it is continuous with the quadrangular lobule in the hemispheres. It is divided by the preclival fissure into an