A system of obstetrics . Fig. 148.—Human Embryo in situ within its Membranes, 4 weeks old, natural size. Fig. 149.—Human Embryo in the Fourth Week, magnified : 1, amnion removed in part of the dorsal region; 2, umbilical vesicle; 3, omphalo-mesenteric duct; 4, inferior maxillary tubercle of first pharyngeal arch; 5, superior maxillary tubercle from the same arch; 6, second pharyngeal arch ; 7, third; 8, fourth; 9, eye; 10, primitive auditory vesicle; 11, anterior extremity; 12, posterior extremity; 13, umbilical cord ; 14, heart; 15, liver. During the first month the human embryo is indistingu
A system of obstetrics . Fig. 148.—Human Embryo in situ within its Membranes, 4 weeks old, natural size. Fig. 149.—Human Embryo in the Fourth Week, magnified : 1, amnion removed in part of the dorsal region; 2, umbilical vesicle; 3, omphalo-mesenteric duct; 4, inferior maxillary tubercle of first pharyngeal arch; 5, superior maxillary tubercle from the same arch; 6, second pharyngeal arch ; 7, third; 8, fourth; 9, eye; 10, primitive auditory vesicle; 11, anterior extremity; 12, posterior extremity; 13, umbilical cord ; 14, heart; 15, liver. During the first month the human embryo is indistinguishablefrom that of other mammals. The ovum at this early period may bedescribed as a double-walled, flattened vesicle filled with fluid. Theouter wall bears the branched villi; the inner one is smooth. Theconnection of the villi with the decidua reflexa, and even with thedecidua serotina, is a superficial one, and the ovum is easily separatedfrom its uterine The yolk-sac, at first occupying nearlythe w
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectobstetrics, bookyear1
