. Anatomy, descriptive and applied. Anatomy. 932 THE NERVE SYSTEM The more superficial sections reveal relatively more gray than white substance; deeper sections show a reverse condition, and a section immediately dorsad of the corpus callosum reveals, in each cerebral hemisphere, a very extensive semioval field of white substance, the centrum semiovale, surrounded on all sides by a narrow, convoluted margin of gray substance, the cortex. A close examination of the cut surface, in a fresh and normal brain, shows it to be studded with numerous minute red dots (puncta vasculosa) produced by the
. Anatomy, descriptive and applied. Anatomy. 932 THE NERVE SYSTEM The more superficial sections reveal relatively more gray than white substance; deeper sections show a reverse condition, and a section immediately dorsad of the corpus callosum reveals, in each cerebral hemisphere, a very extensive semioval field of white substance, the centrum semiovale, surrounded on all sides by a narrow, convoluted margin of gray substance, the cortex. A close examination of the cut surface, in a fresh and normal brain, shows it to be studded with numerous minute red dots (puncta vasculosa) produced by the escape of blood from divided blood- vessels. The Cortex.—The cortex, as revealed in such a section, is not of uniform thickness throughout; difi^erent regions show different cortical thicknesses. In general, the cortex is somewhat thicker at the summit of a gyre than in the depths of an adjoining fissure, and it is thicker upon the convex than upon the mesal or basal surfaces. The maximum thickness is observed in the cortex of the central gyres. t IG bSb —Corpus callosum ( and the insula; the minimum at the frontal and occipital poles, notably the latter. Not only is the cortex not of uniform thickness, but it is not of homogeneous structure as seen with the naked eye. An alternation of gray and white stripes is discernible, particularly in the occipital cortex, where a white band runs parallel with the cortical surface between two gray strata; this while stripe, first described by Gennari and usually bearing his name, is also called the band of Vicq d'Az3rr. The preponderance of white substance over gray substance in the cerebrum is a human charac- teristic concomitant with the relative increase of the association cortex, in turn demanding a more intricate interconnection of the ma-ny nerve cells by a multitude of association neurones. These. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - colorat
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1913
