Observations upon the nature and treatment of difficult occipito-posterior positions of the head : founded upon an analysis of twenty-six operative cases / by Angus Macdonald, M.D.

  • Macdonald, Angus, M.D.
Date:
1874
Catalogue details

Licence: Public Domain Mark

Credit: Observations upon the nature and treatment of difficult occipito-posterior positions of the head : founded upon an analysis of twenty-six operative cases / by Angus Macdonald, M.D. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    infeum. It quickly, as I heave said already, healed. Very severe cases of this presentation lead, no doubt, occasionally to the necessity for craniotomy. But luckily I have as yet not met with one which could not be overcome by the use of the forceps. Now, as to the reason why those occipito-posterior cases are _ so frequently defective in regard to their rotation. This is a question really very difScult to-answer. Of course the great distance over which the occiput must glide forwards and the forehead backwards, is of itself sufficient to account for some proportion of the failures; the uterine action proving unequal to complete the task, even though the occipu.t gets well down. But the occiput not getting well down at first, as Dr Uvedale West has pointed out, may also be to blame for some of the defective eases. But, then, even in cases of face to the pubes, the occiput gets ultimately so well down as to be the leading point in the completion of the labour when the mechanism fails, and yet it does not come forward. I do not believe, with Leishman, that in those cases of rotation forwards of the occiput in posterior cases it is necessary, or is the fact, that the occiput requires to get down so far as to be placed within the antero-posterior line of the pelvis which passes horizon- tally through the apex of the ischial spine of the side towards which the occiput is directed. I am satisfied that many, if not all, of those cases which rotate, do so while the occipital protuberance is distinctly above the level of the corresponding spine of the ischium, and indeed that the occipital end of the cranial lever passes over the spine in its motion forwards. Of this I have again and again convinced myself by careful arid prolonged observation while the mechanism of rotation forwards was taking place. I consider that we are too much inclined to regard the foetal head as an unyielding mass in dealing with the initial steps of this movement, and that more of the initial tendency of the head to move forwards is owing to its elastic nature and its capacity for getting moulded under the influence of the pains. The force, then, of the pains transmitted along the spinal column is expended most upon the occipital extremity of the plastic mass formed by the child's head ; and as only in one direction, viz., forwards, can this mass make way, as it is surrounded by unyielding hard structures both posteriorly and laterally, it begins to bulge in the unresisted anterior direction, and thus a tendency is established which no doubt has the effect, in favourable circumstances, to a cer- tain amount, of making the forehead rise somewhat, so as to leave more room for the parts under greatest tension to occupy. It is also to be remembered that the projection formed by the posterior parietal protuberance, in cases of occipito-posterior presentation, acts at a much greater advantage in exerting a tendency for the hind head to glide forwards than it can effect in cases in which the occi-