A System of Midwifery

by Edward Rigby

“In the second chief position, viz. with the anterior surface of the child corresponding to the anterior abdominal parietes of the mother, it is chiefly the left ischium which is either originally situated forwards, or takes this direction as the nates sink through the superior aperture of the pelvis, which latter preserve this oblique direction during the farther progress of the labour, both whilst pressing into the pelvic cavity, and when entering the external passages.

“If the ischia be already born, the anterior surface of the child turns itself to the right and backwards, either immediately, or as the rest of the trunk advances; but the manner in which the head in this case presses through the entrance cavity and outlet of the pelvis, is the same as has already been described.” (Naegelé, op. cit. p. 128, 130.)

It appears to be a law in nates presentations, that whatever may be the direction of the child (first or second position) at the beginning of labour, it will always, if not interfered with, be found with its anterior surface turned towards one or other of the sacro-iliac synchondroses, when the thorax or the shoulders are beginning to pass through the outlet of the pelvis. When the nates have once passed the os externum, the position of the child frequently varies a good deal, the abdomen turning first to one side and then to the other. This is especially the case in the second position, where it is more or less forwards; nevertheless, as labour advances, it will almost invariably turn obliquely backwards, and be born in this position. Dr. Collins is, as far as we know, the only English author who has distinctly noticed this fact. “It is very desirable,” he observes, “the child should be delivered in this position (viz. the back of the child towards the mother’s abdomen,) as it renders the getting away of the head much less difficult; yet where there has been no interference by the attendant in the previous part of the labour, he will rarely find it necessary to alter subsequently the child’s position, the breech naturally making the turn above alluded to in its passage.” (Practical Treatise on Midwifery, by Robert Collins, M. D. p. 41.)

It sometimes, although rarely, happens in these presentations, that the head does not rest with the chin upon the breast, but the occiput is pressed against the nape of the neck, as in presentations of the face. The passage of the trunk through the pelvis follows, as above-mentioned, as far as the head: this enters the brim with the occiput in advance, and vertex towards one or other ilium. As it advances through the brim into the cavity of the pelvis, it gradually turns more and more backwards, so that when the body is born, the vertex is turned towards the hollow of the sacrum, and the under surface of the lower jaw behind the symphysis pubis.

The diagnosis of nates presentations is not difficult. The pointed and more or less moveable coccyx, bounded at its broader end by the hard uneven sacrum, and in the contrary direction by the anus, will scarcely admit of a mistake. The tuberosities of the ischia may easily be mistaken, for the malar bone of a face presentation, or even a shoulder, can scarcely be distinguished from them, and the external organs of generation become too much swollen and pressed together to give any certain diagnosis; nor indeed can they be examined in this state without considerable risk of injury. The direction of the sacrum, like that of the forehead in face cases, points out the exact position of the child.

Presentations of the nates, although perfectly natural as far as labour is concerned, are far more dangerous for the child than those of the face, for when the head enters the pelvis, if every thing be not favourable for its passing rapidly through it, the cord is so long compressed that the child is almost certainly lost.

The natural position of the fœtus in utero is admirably adapted for its safe passage through the pelvis under these circumstances, and is what we ought to maintain, as far as possible, during labour. The legs are turned upon the abdomen, the arms are crossed upon the breast, the chin rests upon it, the head being bent forwards, so that the whole forms an oval mass. So long as the child advances gradually, the fundus presses firmly upon the head, and keeps the chin close upon the breast; the head therefore enters the pelvis in the most favourable position possible, and the uterus, not having been suddenly emptied of a part of its contents, continues to act briskly, and presses the head so rapidly through the pelvis, that the child is born without having suffered from any serious pressure upon the cord. As however the body of the child diminishes from its pelvis up to the axillæ, it is very apt to be rapidly expelled as soon as the nates have passed the os externum; and if not, it is but too frequently assisted, as it is called, at the very moment when it ought rather to be supported and prevented from advancing too suddenly. When this is the case, the fundus ceases to press upon the head, the chin quits the breast, and as a space is thus left between them, the arms slip into it, and then turn upwards, so that the head not only enters the pelvis in a most unfavourable position, but, to make matters still worse, it has an arm on each side of it: at this critical moment the uterus, from having been suddenly emptied, ceases to contract, and the head remains so long in the pelvis that the child has no chance of escaping with its life.

Where the child has descended gradually, and the arms have advanced with the breast into the pelvis, if the cord be considerably upon the stretch, a portion should be pulled gently down in order to relax it, and we should endeavour as far as possible to guide that part of it which is within reach towards one of the sacro-iliac synchondroses, being less liable there to suffer from pressure. One or two fingers should be introduced to bring down the arms, which are now coming into the lower part of the hollow of the sacrum: they should be hooked down by the bend of the arm, in order to prevent the humeri from sticking across the passage. When this has been effected, the shoulders follow as the head descends through the pelvis. The body of the child should now be wrapped in warm flannel, and two fingers passed up towards the face: the lower jaw must not be trusted to in bringing the head through the pelvic outlet and os externum, for it may easily be broken: the fingers should be applied one on each side the nose, and the chin depressed as much upon the breast as possible, by which means the head will come in a much more favourable direction, and pass readily.

In no case is so much mischief done by impatient interference as in presentations of the lower end of the child. This is still more so in footling cases, for here the soft parts are not so well dilated as in nates presentations, where the child comes double: hence the fact, that presentations of the feet are easier to the mother but more dangerous to the child. In either case, the passage of the head through the pelvis must ever be attended with considerable hazard, for if it be delayed beyond a short time, the child’s death is certain. “The more gradually the nates and body of the child are expelled, the quicker will its head pass through the pelvis, and the better will be its chance of being born alive.” (Obstet. Memorand. 2d ed.) Hence, therefore, if the pains are slow at this moment, it will be desirable to rouse them with a dose of ergot; and if the child gives a convulsive twitch, the forceps ought instantly to be applied. The result of Professor Busch’s practice in the lying-in hospital at Berlin shows, that by the timely use of the forceps a large majority of children may be saved. For the same purpose, the nurse should be instructed to have a warm bath in readiness, with some spirit, &c. for resuscitating the child the moment it is born.

The numbers which we subjoin are taken from the cases in the Dublin Lying-in-Hospital, under the late Dr. Joseph Clark and Dr. Collins, from the private practice quoted in Dr. Merriman’s Synopsis, and from the General Lying-in-Hospital.