The principles and practice of obstetrics . ame hav-ing been applied to it by Fallopius. It usually measures from sixto eight inches in diameter, and, at its centre, is from one inch toone inch and a half in thickness, gradually becoming less so towardits border or circumference. But while these may be consideredthe standard measurements, it must be remembered that there areoccasionally exceptions; for example, the after-birth at full termwill sometimes greatly exceed these dimensions, while again it willfall short of them. Divisions of the Placenta.—The placenta is divided into twosurfaces—th
The principles and practice of obstetrics . ame hav-ing been applied to it by Fallopius. It usually measures from sixto eight inches in diameter, and, at its centre, is from one inch toone inch and a half in thickness, gradually becoming less so towardits border or circumference. But while these may be consideredthe standard measurements, it must be remembered that there areoccasionally exceptions; for example, the after-birth at full termwill sometimes greatly exceed these dimensions, while again it willfall short of them. Divisions of the Placenta.—The placenta is divided into twosurfaces—the fcetal and maternal. The foetal surface (Fig. 45) issometimes called the membranous, because the chorion and amniosboth pass over it; it likewise has received the name of arbores-cent, for the reason that the distribution of the two umbilical arte-ries, and one vein, give to it that peculiar appearance resemblingthe branches of a tree. This surface of the placenta is smooth,and, as it were, glistening. The maternal portion, sometimes. *lQio- Fig. 46. denominated uterine, is in contact with the uterus ; and, while theintegrity of the contact is preserved, this surface is also smooth, itslobes or cotyledons being more or less in close juxtaposition. the afterbirth be examined, subsequently to its detachment fromthe uterus, the maternal surface will exhibit an irregular, brokenaspect, ami distinct separations recognised among the various lobescomposing it. (Fig. 46.)Blood-vessels of the Placenta.—Physiologically speaking, it may 248 THE PRINCIPLES AND PRACTICE OF OBSTETRICS. be said that the placenta is divided into two distinct portions; oneappertaining to the foetus, and the other to the mother; for, as weproceed further in the examination of this subject, it will be shownthat there are two distinct, independent circulations in the organ ;one on the fcetal surface, composed of the vessels in the umbilicalcord; the other, on the maternal surface, composed of the ut
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Keywords: ., bookcentury1800, bookdecade1860, bookpubli, booksubjectobstetrics
