. Diseases of the nervous system . borderof the hemispheres, usually making two bends (the superior and inferiorgenu of the sulcus centralis) and then runs downward terminating a littleabove the horizontal limb of the Sylvian fissure. The two principal fissuresare chiefly located upon the median surface of the occipital lobe, and arethe fissura parieto-occipitalis which usually extends somewhat upon the lateralsurface, and the fissura calcarina, these uniting at an acute angle and termi-nating immediately below the splenium of the corpus callosum, in the sur-roundings of which in the cortex, t
. Diseases of the nervous system . borderof the hemispheres, usually making two bends (the superior and inferiorgenu of the sulcus centralis) and then runs downward terminating a littleabove the horizontal limb of the Sylvian fissure. The two principal fissuresare chiefly located upon the median surface of the occipital lobe, and arethe fissura parieto-occipitalis which usually extends somewhat upon the lateralsurface, and the fissura calcarina, these uniting at an acute angle and termi-nating immediately below the splenium of the corpus callosum, in the sur-roundings of which in the cortex, the sense of sight in man appears to besituated. The sulcus corporis callosi, sometimes also known as the fissurahippocampi, and the fissura cltorioidea, which is scarcely perceptible in thedeveloped brain, are principal fissures in the embryo but do not proceed tocomplete development. To facilitate its description the division of the hemispheres of the cere-brum into separate lobes formed as far as possible by the main fissures is. Fig. 5.—Lateral View of the Brain. (After Edinger.) important. Hence, we differentiate a frontal lobe situated in front of thecentral fissure and extending downward to the Sylvian fissure, also a parietallobe which begins behind the central fissure and is also limited below by theSylvian fissure. The boundaries of the temporal and occipital lobes are not sodistinct, but by the aid of the fissura parieto-occipitalis and the Sylvian fissure,which must be extended, these may be determined. The island situated at thebase of the Sylvian fossa is to be regarded as a special portion of the frontal lobe, which in no animal known to us, not even the anthropoidapes, attains the development that it does in man, has three surfaces, lateral,median, and basal. The last is adjacent to the osseous roof of the orbit,and is therefore called the orbital surface. On the lateral surface we invariablydifferentiate three fissures, the sulcus prcecentralis which
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectnervoussystem, bookye
