ADHESIONS OF TIIE PLACENTA.
The two most complete works upon this subject are those of Van Lyn seele, and of Regan The latter found adhesions in cases of abortion, of premature labor, and of delivery at term, and showed them to be due to such pathological processes as degeneration of or hemorrhage into the pla centa, and inflammations of its parenchyma, of the decidua, and of the tissues about the uterus.
lst. In cases of abortion and premature labor there is an arrest in the, process of involution of the placenta. Retention of the placenta occurs from the intimate union between the maternal placenta and the uterine parietes, from separation of the maternal from the Petal placenta, from the want of energy in the uterine contra4tions due to incomplete develop ment of the muscular layer, from the resistance of the cervix, and from pathological processes of the uterus, of the appendages of the egg, and. of the organs in the neighborhood of the womb.
2d. In cases of vesicular mole, to which we shall presently return.
3d. In case of exudative processes, and of extravasations into the pla centa.
That adhesions from primaty exudations from the uterine wall do occur, has been anatomically demonstrated. (Obs. of Stradfort, Chiari, Clay, Brailn, Wrisberg, Hegar, Simpson, Meckel, Hfiter, Siebold, Stoltz). The placental tissue may appear solid, antemic, and white, or, on the contrary, it may be soft, friable, and brownish, but it is firmly attached t,o the uterus by the uniting layer. Thus the placenta is easily torn, and frag
ments remain in the uterus at the time of delivery.
Some authors have described adherent placentas in a condition of atrophy; they were dry, small, and antemic.
When the adhesions are secondary, they occur in consequence of exu dations and extravasations into the parenchyma of the placenta, or be tween it and its membranous covering. The uniting layer of the mucosa participates in the lesion by extension of the morbid process, by the irri tation which the pathological product causes in its vicinity, and by the modific,ations of the circulation which it effects. The effusions poured out between the membranous coverings and the fcetal surface of the pla centa most often extend to the periphery, following the ramifications of the umbilical vessels along the external surface of the chorion, and with prolongations extending to the decidua.
These placental adhesions may be spread out as membranes or may form bands and cords. They rarely extend over the entire uterine sur face.
Causes. —These may be diseaaes of the fcetus, of the umbilical vessels, of the amnion, or of the chorion; or they may be obstacles to the umbi lical circulation, hemorrhages and effusions, or endotnetritis.
Hegar believes that he can recognize them during pregnancy, but the symptoms that he gives are of very doubtful value.