. An American text-book of obstetrics. For practitioners and students. st ol/ Fig. 121.—A, mesial section through brain of a human fetus of two and a half months (His): eh, cere-bral hemisphere; o, optic thalamus; fm, foramen of Monro; olf, olfactory lobe; p. pituitary body; mo,medulla oblongata ; eg, corpora quadrigemina ; cb, cerebellum. B, brain of human fetus of three months(His): olf, olfactory lobe; est, corpus striatum; cq, corpora quadrigemina; cb, cerebellum; mo, medullaoblongata. The relative position of the mid-brain, however, undergoes great change, itsoriginal situation as the hig
. An American text-book of obstetrics. For practitioners and students. st ol/ Fig. 121.—A, mesial section through brain of a human fetus of two and a half months (His): eh, cere-bral hemisphere; o, optic thalamus; fm, foramen of Monro; olf, olfactory lobe; p. pituitary body; mo,medulla oblongata ; eg, corpora quadrigemina ; cb, cerebellum. B, brain of human fetus of three months(His): olf, olfactory lobe; est, corpus striatum; cq, corpora quadrigemina; cb, cerebellum; mo, medullaoblongata. The relative position of the mid-brain, however, undergoes great change, itsoriginal situation as the highest part of the entire encephalon being gradually 128 AMERICAN TEXT-BOOK OF OBSTETRICS. appropriated by the enormously developed cerebral mantle formed by the rapid-growing cerebral hemispheres ; in consequence of the covering in of the mid-brain thus effected, the derivatives of this segment, as the corpora quadri-gemina, occupy a position in the base of the adult brain instead of theirmorphologically normal place. The extent to which the cerebral mantle c calhn. int/ Fig. 122.—Fetal brain at the beginning of the eighth month (Mihalkovics): A, superior, B, lateral, C,mesial surface : R, fissure of Rolando ; pre, precentral fissure ; %, Sylvian fissure ; intp, interparietal fissure ;poc, parieto-occipital fissure; pll, parallel fissure; callm, calloso-marginal fissure; unc, uncus ; calc, calca-rine fissure. covers the remaining parts of the encephalon, including the cerebellum, isdistinctive of the human brain (Figs. 121, 122). The inter-brain undergoes great differentiation, its derivatives forming numer-ous highly specialized organs, among which are the eyes and the pineal andpituitary bodies. For the complicated details of the development of thevarious parts of the brain the reader must be referred to the special works onembryology. The following table, however, modified from Hertwig, will serveas a general indication of the genetic relations existing between the more i
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectobstetrics, bookyear1
