A System of Midwifery

by Edward Rigby

Farther experience has shown that, so long as the pelvis is of the natural size, the head can be born in this position without peculiar difficulty, the soft parts usually require a little more dilatation than where the cranium presents, and, therefore, this stage of the labour is generally somewhat slower. Although presentations of the face are not so favourable for the child as those of the cranium, they stand next to them in point of safety. Where the cranium presents, a slight misproportion between the head and pelvis produces little or no increase of difficulty to the passage of the child; but under similar circumstances, where the face presents, the difficulty may become very serious, for if the labour is prolonged, “the brain and vessels of the neck,” observes Smellie, “will be so much compressed and obstructed as to destroy the child.” (Explanation to table 25.) A similar view has been given by Dr. Denman, and still more recently by Professor Chaussier, of Paris, and Professor Naegelé; the two latter authorities examined the brain in several still-born children where the face had presented, and invariably found the cerebral vessels gorged with blood.

The presenting side of the face when born is frightfully distorted by the livid swelling above-mentioned; the mouth is pulled to one side and upwards; the angle of the eye is drawn downwards, and the corresponding ala of the nose scarcely discernible amid the purple mass of tumefaction: the less this is meddled with the better, for in the course of a day or two the parts will have returned to their condition; whereas, if friction or hot poultices, &c., be used, ulceration may be the result, and produce considerable disfigurement.[80]

Nates presentations. “After the presentations of the cranium those of the nates are the most frequent in point of occurrence, and also the most natural,” says the celebrated Boer, in the work already quoted. Under the term nates presentations, we include those of the knees and feet, as these latter presentations can only be looked upon as modifications of the former. Professor Naegelé, jun., in his new edition of the admirable essay upon the mechanism of labour, published by his father, in Meckel’s Archiv. für die Physiologie, has very properly brought these different positions under one head, viz. “positions of the pelvic extremity of the child:” as, however, we possess no word in English to express this, we shall attain the same object by considering knee and footling births as mere modifications of breech presentations.

“As regards the relative situation of the limbs to the body of the child, the position is the same as in the two genera of head presentations above described, viz. the knees are usually drawn up to the abdomen, the feet close to the nates, so that not unfrequently they may both be felt together at the beginning of labour, and afterwards descend into the pelvis and are born together. Sometimes the feet (or perhaps only one foot) are felt higher above the brim than the nates; in which case, as the nates descend they rise, and are turned upon the abdomen and breast of the child, and descend with these parts as labour advances. Frequently it is the reverse: the feet are somewhat lower than the nates; they are felt in the os uteri at the beginning of labour, and descend before them as labour advances. It is rare that the knees come down before the nates during the farther progress of labour, and it is not probable that they are ever found alone in the os uteri at the commencement of it.” (H. F. Naegelé, Mechanismus der Geburt, 1838, p. 57.)

The nates may present in two ways, either with the back of the child forwards, or with its abdomen forwards: of these the former occurs most frequently; thus of 161 cases which were accurately ascertained at the lying-in hospital of Heidelburg, 121 were observed with the back of the child forwards, and 40 with it backwards: in either of these positions the transverse diameter of the child’s pelvis always corresponds to one or other of the oblique diameters.

“Labours with the nates or feet presenting, follow certain laws quite as much as those where the head presents, only that one more frequently sees deviations from them, both with respect to the manner in which the child presents at the time of labour, and its passage through the pelvis; but where, under a proper state of the other requisites for healthy parturition, no prejudicial result occurs.” (Naegelé, on the Mechanism of Parturition, transl. § 19. p. 128.) “In every case, whether the nates have at first a completely transverse or oblique direction, they will be always found, on pressing lower into the superior aperture of the pelvis, to have taken an oblique position; and that ischium, which is directed anteriorly, to stand lowest. They pass through the entrance cavity and outlet of the pelvis in this position, which is oblique, both as to its transverse diameter as well as to its axis.”

Thus, if in the first species the left ischium were either originally directed more or less forward, (which is usually the case,) or had taken this direction in passing through the superior aperture, the nates descend in this direction into the pelvic cavity, with the left ischium during the whole time standing lowest; and this is the part, during the farther progress of the nates, which first passes between the labia as the os externum dilates. As they advance, and while the left ischium, which is directed forwards and always somewhat to the right, comes completely under the pubic arch and presses against it, the other ischium, which is situated in the opposite direction, and which has to make a much greater circuit, passes forwards over the strongly distended perineum, so that, when the pelvis is born, the abdomen of the child will be directed to the inner and posterior surface of the mother’s right thigh.

“The rest of the trunk follows in this position, and as the breast approaches the inferior aperture of the pelvis, the shoulders press through its superior aperture in the direction of the left oblique diameter; and during its passage (viz. the breast) through the pelvic outlet, the arms and elbows which were pressed against it are born at the some moment. But whilst the shoulders are descending in the above-mentioned oblique position, the head, which during the whole progress of the labour rests with its chin upon the breast, presses into the superior aperture in the direction of the right oblique diameter, (viz. with the forehead corresponding to the right sacro-iliac synchondrosis,) and then into the cavity of the pelvis in the same direction, or one more approaching the conjugate diameter. After this, it presses through the external passage and the labia, in such a manner, that whilst the occiput rests against the os pubis, the point of the chin, followed by the rest of the face, sweeps over the perineum as the head turns on its lateral axis from below upwards.

“But it is sometimes the right ischium, which, in this chief division, is either originally turned forwards, or in the process of time assumes this direction. In this case the child passes through the pelvis in the same manner as before, only with the difference, that the surface of the body takes of course a different position with respect to the pelvic parietes, viz. its anterior surface, which in the former case corresponded to the right side of the pelvis, will be directed to the left, and the head will press through the superior aperture of the pelvis, in the direction of the left oblique diameter (the forehead passing before the left sacro-iliac synchondrosis.)”

“As in positions of the cranium, the swelling of the integuments is chiefly met with on that parietal bone which during the passage of the head, is situated lowest, and on that spot with which it enters the external passage, so in this case the livid coloured swelling appears on that part which, directed forwards, was situated lowest during the passage of the nates, and with which the nates were born.