Das Wachstum der Chorionzotten vom II. bis X. Monat

Development and Structure of the Human Placenta From the End of the 3rd Month of Gestation

“…Hormann's graphs show there is a regular decrease in average villous diameter up to the tenth month of pregnancy. The average diameters for the early months of pregnancy were: fixed, 170 p, unfixed, 140 p. For the tenth month placentae the corresponding figures were : fixed, 70 p, unfixed, 50 p. Knopp (1960), who applied the statistical method elaborated by Linzbach (1947) to the problem of the growth of the "chorionic villi", also demonstrated the marked decrease in the diameter of the terminal villi as they increase in number during gestation. Recently Aherne and Dunnill (1966a and b) have produced frequency distribution histograms at various gestation ages (18, 34 and 40 weeks) showing a modal diameter of the villi to be constant at 40 to 49 p. Our own data are all based on fixed material and although we have not yet applied to our measurements the elaborate statistical techniques used by Hormann and Knopp, none of our measurements fall outside the ranges indicated by these investigators.…”

“…(Foetus, 80 mm. but little information is available on quantitative changes in placental structure and proportions during development, most of the published data relating to specimens at, or near, full-term (see Wilkin, 1958, 1965a andJaroschka, 1959;Knopp, 1960;and Aherne and Dunhill, 1966a and b).…”

“…As the result each column penetrates the peripheral trabecular syncytium and the cytotrophoblastic cells mushroom outwards circumferentially through this syncytium and in the junctional zone between it and the decidua. Here the fusion of the proliferations from the cell columns of adjacent villi results in the estab-Peters, 1899; Kollmann, 1901 ;Herzog, 1909;Grosser, 1909Grosser, , 1927Lazitch, 1913;Spanner, 1935;Ortmann, 1938;Stieve, 1941;Peter, 1943Peter, , 1950Wislocki and Bennett, 1943;Baker et al, 1944;Hormann, 1948Hormann, , 1951Hormann, , 1953Bee, 1953;Lemtis, 1955/56;Snoeck, 1958;Bargmann and Knoop, 1959;Mazanec, 1959;Amstutz, 1960;Boyd, 1960, 1966;Knopp, 1960;Tenzer, 1962;Crawford, 1962;Becker, 1963;Fox, 1964a lishment of the cytotrophoblastic shell. Each initial villus is attached at its proximal (chorionic) end to the chorionic plate and at its distal (basal) extremity to the cytotrophoblastic shell.…”

“…Consequently it is difficult to make and to record, for purposes of comparison, quantitative measurements of their dimensions. Contributions to the technical problems raised in making the measurements and to the analysis of the data themselves, are presented by Hormann (1951), Vanden Eynden (1957, 1958), Jaroschka (1959), Knopp (1960Knopp ( , 1962 and Aherne and Dunnill (1966a and b).…”

“…In the last four months of pregnancy there are extensive regions where, including its brush border the syncytium is much attenuated but even in the mature placenta there are many villi on which it remains thick (Colour Plates 1 and 11). Knopp (1960) gives 6.5 p as the mean value for syncytial thickness in the tenth month. Our own electron microscopic measurements are given in Table 11; the findings are selective but confirm the impression from light microscopy that with advance in foetal age much of the syncytium becomes progressively thinner.…”