A treatise on the science and practice of midwifery / By W. S. Playfair.
- William Smoult Playfair
- Date:
- 1885
Licence: Public Domain Mark
Credit: A treatise on the science and practice of midwifery / By W. S. Playfair. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
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![uterus greatly hypertrophied. The second, the decidua reflexa, is closely applied round the ovum, and it is probably formed by the sprouting of the decidua vera around the ovum at the point on which the latter rests, so that it eventually completely surrounds it. As the ovum enlarges, the decidua reflexa is necessarily stretched, until it comes everywhere into contact with the decidua vera, wath which it firmly unites. After the third month of pregnancy true union has occurred, and the two layers of decidua are no longer separate. The decidua serotina, which is described as a third portion, is merely that part of the decidua vera on which the ovum rests and where the placenta is eventually developed. Vietvs of William and John Hunter.—It is needless to refer to the various views which have been held by anatomists as to the structure and formation of the decidua. That taught by John Hunter was long believed to be correct, and down to a recent date it received the adhe- rence of most physiologists. He believed the decidua to be an inflamma- tory exudation, which on account of the stimulus of pregnancy was thrown out all over the cavity of the uterus, and soon formed a distinct lining membrane to it. When the ovum reached the uterine orifice of the Fallopian tube it found its entrance barred by this new membrane, which accordingly it pushed before it. This separated portion formed a covering to the ovum and became the decidua reflexa, while a fresh exu- dation took place at that portion of the uterine wall which was thus laid bare, and this became the decidua vera. Williani_Hunter had much more correct views of the decidua, the accuracy of which was at the time much contested, but which have recently received full recognition. He describes the decidua in his earlier writings as a hypertrophy of the] uterine mucous membrane itself—a view which is now held by all! physiologists. Structure of the Decidua.—When the decidua is first formed, it is a hollow triangular sac lining the uterine cavity (Fig. 49), and having three openings into it—those of the Fallopian tubes at its upper angles, and one, corresponding to the internal os uteri, below. If, as is gener- ally the case, it is thick and pulpy, these openings are closed up and can no longer be detected. In early pregnancy it is well developed, and continues to grow up to the third month of utero-gestation. After that time it commences to atrophy, its adhesion with the uterine walls less- ens, it becomes thin and transparent, and is ready for expulsion when delivery is effected. When it is most developed, a careful examination of the decidua enables us to detect in it all the elements of the uterine mucous membrane greatly hypertrophied. Its substance chiefly consists of large round or oval nucleated cells and elongated fibres, mixed with the tubular uterine gland-ducts, which are much elongated, and filled with cylindrical epithelium cells and a small (jnantity of milkv fluid. According to Friedlander, the decidua is divisible into two layers : the iiiiier, being formed by a prolifi'ration of the corpuscles of the sub-cpi- tlielial connective tissue of the mucous membrane; the deeper, in contact with the uterine walls, out of flattened or compressed j^land-ducts. In an early abortion the extremities of these ducts may be observed by a lens, on the external or uterine surface of the decidua, occujwing the summit of minute projections sei)arated from each other by depressions.](https://iiif.wellcomecollection.org/image/b2121072x_0111.jp2/full/800%2C/0/default.jpg)
