BALLOITEMENT.
Ballottement is a peculiar sensation that is felt upon giving the fcetus an impulse so that it moves wholly or in part in the uterus; when, in fact, motion is imparted to the fcetus.
When this impulse is transmitted through the abdomen, it is abdominal ballottement, when through the vagina, it is vaginal ballottement. We will reserve the latter until we come to study the touch.
Abdominal ballottement may be effected in different ways. Placing the hands upon opposite sides of the abdominal walls, and communicating a sharp impulse upon one of them, the fcetus can be felt to be displaced, and to strike the other hand with a sensation of shock. Or a single hand may be laid upon the foetal part, and, upon giving an impulse to it, it may be felt to return and strike the hand. In both cases the sensation perceived by the fingers is analogous to that perceived when, with the finger, a piece of ice floating in a glass of water is sharply tapped. This sensation is never more pronounced than when the displacement of the foetus is only partial, as in what is called cephalic ballottement. We have seen, that it is especially when the head is in the upper part of the uterus that it can be perceived. When both hands are used, there is a double
sensation of shock, of departure and.retum of the fcetus. For ballotte ment to be practised, certain conditions are necessary: 1st. The uterus must be developed enough to project considerably above the pubes. 2d.
The fcetus must be developed and solid enough to offer a certain resist— MCC. 3d. There must be a certain quantity of liquor amnii, as compared with the bulk of the fcetus, to insure mobility. It is, therefore, only after the fourth month of pregnancy that ballottement can be properly obtained; and it is especially useful at the sixth and seventh months, when the conditions most favorable for it are present. Before this, neither fcetus nor uterus are sufficiently developed; later, the foetus is too large, and the quantity of amniotic fluid is too small. Of course hydram nion, twin pregnancies, etc., prevent ballottement.
Ballottement is a certain sign of pregnancy; nevertheless, Pajot has re corded a case in which he was able to perceive it, and yet in which the woman was suffering not from pregnancy, but from a multilocular ovarian cyst.