A system of midwifery / by Edward Rigby.

  • Rigby, Edward, 1747-1821.
Date:
1844
Catalogue details

Licence: Public Domain Mark

Credit: A system of midwifery / by Edward Rigby. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    ovum gradually increases in size. The external layer of decidua is called decidua vera ; the internal or reflected portion is called the decidua reflexa, having received this appellation from its discoverer Dr. Hunter. These mem- branes would, as Dr. Baillie has correctly observed, be more correctly named the decidua uteri and decidua chorii: the decidua chorii or reflexa is reflected inwardly from above downwards; it is connected on its inner surface with the chorion ; externally it is unattached, whereas the decidua uteri or vera is un- connected on its inner surface, but attached to the uterus externally. The membrana decidua differs in its arrangement from that of a serous membrane, inasmuch as it is not only reflected so as to cover the chorion, but at the point of reflexion it is continued over the chorion externally, where it forms the placenta, so that the chorion is enclosed in all directions by the de- cidua: this latter portion, however, is not formed till about the middle of preg- nancy. The decidua uteri or vera does not extend further than the os uteri internum, which is filled up by the plug of tough gelatinous substance above described ; the decidua chorii or reflexa, from its forming the outer covering of the chorion, of course passes over the os uteri. Accordingto Mr. John Hunter, the decidua vera is continued some little way into the Fallopian tubes, more especially on that side where the corpus luteum has been formed ; it is perforated at the points where the Fallopian tubes enter, as well as at the os uteri, a fact which is beautifully shown in Dr. Hunter's last plate : but this does not continue long, for, as Mr. John Hunter observes, the in- ferior opening becomes closed in the first month, and, according to Lobstein's ob- servations, the openings of the Fallopian tubes are closed after the second month. Where the decidua reflexa is beginning to pass over the chorion, there is, at an early period of pregnancy, an angle formed between it and the decidua, which lines the uterus; and here the decidua is often extremely thin, and perforated with small openings so as to look like a piece of lace. In proportion as pregnancy advances, the decidua reflexa becomes gradually thinner and thinner, so that at the fourth A month it forms an extremely fine layer / \ covering the chorion; it comes at the Membrana decidua. same time more and more closely in con- The lower orifice corresponds to the tact with the decidua, which lines that part os uteri, the two upper ones to the Fal- of the uterus to which the placenta is not lopian tubes. From Dr. Hunter. fixed, till at length they adhere together. * That portion of the decidua which passes between the placenta and uterus during the latter half of gestation, is called the placental decidua, the description of which will be given with that of the placenta. To Dr. W. Hunter are we indebted for the first correct description of the decidua; indeed, so excellent is it, that the membrane has been called after him the decidua of Hunter. Although he was the undoubted discoverer of the re- flexa, the existence of the decidua was distinctly noticed by Burton in 1751. In stating the post mortem examination of a woman, who died undelivered at the full time of pregnancy, he says, Upon wiping the inside of the uterus very gently with a sponge, there seemed to be pieces of a very tender thin trans- parent membrane adhering to it in such parts of the uterus where the placenta did not stick to it; but as the womb was somewhat corrupted, and the membrane so very tender, we could not raise any bulk of it so as to be certain what it was. (Burton's Midwifery.) * Observations by Dr. Baillie, in the posthumous work of Dr. W. Hunter, on the Anatomy of the Gravid Uterus,