A study of the human placenta, physiological and pathological / by Thomas Watts Eden.

  • Eden, Thomas Watts, 1864-1946.
Date:
[1894?]
Catalogue details

Licence: Public Domain Mark

Credit: A study of the human placenta, physiological and pathological / by Thomas Watts Eden. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    to penetrate it for any considerable distance, but they become attached in large numbers to its surface. Even at the beginning of pregnancy the decidua is roughly divisible into two layers: a superficial layer, in which the haemorrhages are most numerous, and a deep layer containing the dilated glands. In the third stage, however, the serotina consists of two perfectly distinct layers: a superficial compact layer, and a deep cavernous layer (Plate XXL Fig. 12). The, superficial layer is composed of closely-packed decidual cells, and is traversed by the placental arteries and veins, which open upon its surface into the intervillous spaces. There are no glands in this layer. The surface is covered by a stratum of fibrin. The deep or cavernous layer contains a network of irregular, dilated, glandular channels. In the third and fourth months, many of the glands retain a well-preserved lining of cubical epithelium. Towards the end of pregnancy, only occasional small groups of these cells remain; so that the channels are often mistaken for veins. The arteries and veins, of course, also pass through it. The decidual stroma consists of cells smaller and more closely packed than those of the superficial layer. It is through the deep layer that separation of the placenta occurs when it is normally shed. The course of the maternal vessels deserves more detailed notice. The fact that these vessels opened into the intervillous spaces was proved long before the details of the process by which this communica- tion becomes established were worked out. Waldeyer (43) first succeeded in making satisfactory observations upon this point, and his research is one of the landmarks of the study of the placenta. Very little has since been added to his description of the course of the maternal vessels in the adult placenta. There are very few capillaries in the serotina at this period; the arteries and veins open directly into the intervillous spaces, but before doing so they give off a few nutritive branches to the serotina. The arteries run a spiral course right through the uterine wall. In many naturally shed placentae, the torn ends of these arteries may be detected upon the maternal surface. In the muscular wall of the uterus, they show the usual three coats, and round many of them is found a semi- circular, peri-lymphatic space. When the artery leaves the muscular wall the middle coat disappears, and in the serotina there is only an endothelial layer surrounded by a loose fibrous sheath. The artery enters the serotina vertically, but alters its course so as to open obliquely into the intervillous spaces. The fibrous sheath ceases abruptly just before the artery opens. Waldeyer asserts that the endothelial layer may be traced not only up to the opening, but for some distance over the surface of the adjacent serotina. Others believe that it disappears with the fibrous sheath, so that the actual aperture is formed only by the rounded edges of the decidual tissue (Plate XXII. Figs. 15 and 16). The veins form large sinuses in the muscular wall of the uterus.