Diseases of the nervous system / edited by Archibald Church.

Date:
1908
Catalogue details

Licence: In copyright

Credit: Diseases of the nervous system / edited by Archibald Church. Source: Wellcome Collection.

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    the outer, darker, and largest portion is called the putamen. The lateral surface of the putamen is parallel with the island of Reil from which it is separated by a narrow gray streak, the claustrum; and between the latter and the putamen runs the narrow medullary lamina, the external capsule. Poste- riorly to the nucleus lentiformis and close to the tail of the nucleus caudatus, communicating with both, is the sharply defined gray mass, the amygdala, which is also united with the hippocampus major. The relation of these gray ganglia to each other and to the adjacent portions of the brain, and their physiologic importance in man and in the higher mammals, can be deter- mined only by microscopic and comparative anatomical examination, and in spite of many experiments and pathologic observations we are still completely in the dark concerning these. The cerebral hemispheres are united with one another by several com- missures : (1) The most important of these is the corpus callosum which is seen upon the floor of the great medial, longitudinal fissure. Besides this portion of the corpus callosum, called the truncus, we find also the posterior splenium corporis callosi which is thickened and lies above the corpora quad- rigemina, anteriorly bending somewhat downward the genu corporis callosi, which may be followed backward to the fornix as a narrow line, the rostrum. Between the corpus callosum and the rostrum the septum pellucidum spreads out in the form of two thin plates and contains the ventriculus septi pellu- cidi. (2) Below the corpus callosum the fornix unites both hemispheres in the form of a narrow band (the fimbria), passing out of the lower horn of the lateral ventricles at each side in the region of the cornu ammonis, uniting upon the two crura fornicis, passing along the lower surface of the corpus callosum, to divide in front at the lower end of the septum pellucidum into two columns, the columnce fornicis; the latter extend to the base of the brain, to the corpora mamillaria. (3) The anterior commissure as a white band joins the hemispheres in front of the columnae fornicis, which unite the basal portions of the temporal and frontal lobes. In their entire extent the cerebral hemispheres are permeated by cavities, the lateral ventricles mentioned above. These cavities pass arch-like from above anteriorly downward posteriorly and permit the differentiation of a middle portion, the cella media, and three horns, the anterior horn which passes into the temporal lobes, the posterior horn entering the occipital lobe, and the lower horn extending to the temporal lobes. The cella media shows upon its floor, besides other structures, the tail of the nucleus caudatus, while above is the middle portion of the corpus callosum. The anterior horn passes around the head of the nucleus caudatus into the posterior portion of the temporal lobe, and is bounded above by the corpus callosum, while medially it reaches the septum pellucidum. The posterior horn runs dorsally close to the occipital pole. The most important structure upon its base is the calcar avis or pes hippocampi minor, which is produced by the sinking in of the fissura calcarina on the medial surface of the occipital lobe. Here are also a number of fiber strands which play a role in the law of cerebral localization; the optic radiation of Gratiolet which passes from the thalamus opticus to the occipital lobe, the unilateral interruption of which produces hemianopsia, and the fasciculus longitudinalis inferior, which connects the temporal and occipital lobes. The posterior horn is covered from above by the fiber masses
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