VERTEX PRESENTATIONS.
We have already seen the causes of vertex presentations, and have studied the positions of the ketus, in detail, in considering abdominal palpation. We are thus, at once, brought to the diagnosis of vertex presentations, which is made by palpation, auscultation and vaginal touch, and should be made before labor, during labor, both before and after the rupture of the membranes.
a. Before Labor—Palpation.—Palpation permits us to discover, at the lower part of the abdomen, a hard, round, smooth, prominent object, and at the upper part, another body broader, equally prominent, but less round and hard, beside which we recognize little mobile objects which may be displaced by the fingers, and which are the inferior foetal extremi ties. On one side of the uterus or the other one feels a resisting, ex panded mass, which connects the upper and lower tumor. This masa is the back.
Auscultation.—The foetal heart-beats are heard below the line which divides the uterus into two equal parts.
Vaginal Touch.—By this means one feels a hard, round, prominent body, more or less engaged, which sometimes imparts a sensation like parchment to the finger, or upon which we may feel, when the inferior segment is thin, the sutures and the fontanelles. In front of this tumor, at a variable height and generally on the left, one feels the little eminence and depression formed by the more or less completely effaced cervix.
b. During Labor.—The signs furnished by palpation and auscultation are the same, but palpation is more difficult on account of the uterine contractions. These methods of examination must, therefore, be em ployed in the interval between the pains. Vaginal touch furnishes differ ent information according as it is practised before or after rupture of the membranes. Before the rupture of the membranes, vaginal touch varies according as it is employed during the pains or during the inter vals. If we palpate during the pains, we feel the 08 more or less dilated, more or less thick, more or less rigid, and occupying it, the tense, project ing bag of waters. Behind the bag of waters we feel the head, more or lees separated from it, according to the quantity of the liquor amnii. The
signs thus obtained are generally not very plain. The interval between the pains is, therefore, the time for palpation. At this time we feel the head, which is recognized by the sutures and the fontanelles, and which clears up all doubts regarding the nature of the presentation. If the head is mobile, not having engaged, it is a little less easy to recognize. Then it is well to depress .the hypogastrium with the left hand, in order to make the head more accessible, and to bring out the sutures and the fontanelles more plainly.
After Rupture of the Membranes.—If the membranes have just rup tured the diagnosis is very easy. Nothing intervenes between the head and the finger, which comes into contact with the sutures and the fonta nelles, and takes cognizance of their shape, extent and direction, thus simultaneously establishing the diagnosis of the presentation and of the position. If the membranes have been long ruptured, however, the diagnosis may be more difficult. Upon that part of the head which is over the pelvic brim, and, consequently, on the accessible part of the head, there is formed an oedematous swelling of the scalp, called the caput succedaneum, which, masking the bones, renders the perception of the sutures and of the fontanelles difficult and paves the way for errors. (Fig. 195). In this case the finger must be pushed higher, beyond this projection. It will thus discover the sutures and the fon tanelles, which prove that the vertex is presenting. If need be, when ever the presentation is above the brim, we must not hesitat3 to carry the finger as far up as possible. This facilitates the diagnosis of a possibly coexisting prolapse of the cord or of a foetal extremity. When the fcetua is dead, and has been macerated for a certain time, the head loses some of its characteristic features. The tissues uniting the bones have lost their solidity, and allow the bones to play upon each other, which gives a characteristic crepitation.