Henry Gray (18251861). Anatomy of the Human Body. 1918.
inferior cornu. Its lower end is enlarged, and presents two or three rounded elevations or digitations which give it a paw-like appearance, and hence it is named the pes hippocampi. If a transverse section be made through the hippocampus, it will be seen that this eminence is produced by the folding of the wall of the hemisphere to form the hippocampal fissure. The main mass of the hippocampus consists of gray substance, but on its ventricular surface is a thin white layer, the alveus, which is continuous with the fimbria hippocampi.
The collateral eminence (eminentia collateralis) (Fig. 740) is an elongated swelling lying lateral to and parallel with the hippocampus. It corresponds with the middle part of the collateral fissure, and its size depends on the depth and direction of this fissure. It is continuous behind with a flattened triangular area, the trigonum collaterale, situated between the posterior and inferior cornua.
The fimbria hippocampi is a continuation of the crus of the fornix, and will be discussed with that body; a description of the choroid plexus will be found on page 840.
FIG. 741 Two views of a model of the striatum: A, lateral aspect; B, mesal aspect. (See enlarged image)
The corpus striatum has received its name from the striped appearance which a section of its anterior part presents, in consequence of diverging white fibers being mixed with the gray substance which forms its chief mass. A part of the corpus striatum is imbedded in the white substance of the hemisphere, and is therefore external to the ventricle; it is termed the extraventricular portion, or the lentiform nucleus; the remainder, however, projects into the ventricle, and is named the intraventricular portion, or the caudate nucleus(Fig. 737).
The caudate nucleus (nucleus caudatus; caudatum) (Figs. 741,742) is a pear-shaped, highly arched gray mass; its broad extremity, or head, is directed forward into the anterior cornu of the lateral ventricle, and is continuous with the anterior perforated substance and with the anterior end of the lentiform nucleus; its narrow end, or tail, is directed backward on the lateral side of the thalamus, from which it is