Obliquely distorted pelvis. A still more remarkable species of pelvic deformity is the pelvis obliquÉ ovata, which, of late years, has been pointed out by Professor NaegelÉ. In this case the pelvis appears awry, the symphysis pubis being pushed over to one side; and the sacrum to the other; one side of the pelvis is more or less flattened, the other bulges out, so that one oblique diameter is shorter, the other longer than natural; and this applies not only to the brim, but to the cavity and outlet of the pelvis. In most cases the sacro-iliac symphysis on that side which is flattened, and to which the sacrum is inclined, is completely anchylosed, not a trace of the division between the ilium and sacrum to be detected, the two bones being completely united into one. In many, the sacrum on this side is smaller than on the other, as if a portion of it had been removed by absorption during the process of anchylosis, or at least not properly developed. When we consider the form of the pelvis, and the appearances which the sacro-iliac symphysis and the sacrum present, we are almost led to conclude that ulcerative absorption must at one time have existed between the sacrum and ilium at this point, probably at an earlier period, by which means more or less bone had been destroyed before the termination of the disease in anchylosis; indeed, we can to a certain extent imitate this peculiar species of pelvic deformity by sawing off the surfaces of the sacrum and ilium which had formed the symphysis, and then putting the bones together again. Still, however, in the various cases which have been collected by Professor NaegelÉ, no proofs could be obtained of disease having existed in the pelvis during early life.

“In none of the cases, the particulars of which have come to my knowledge, has there been any trace of rachitis; nor have any of the symptoms, appearances, and morbid changes been observed which characterize mollities ossium coming on after puberty. None of these cases have been traced to the effects of external violence, as falls, blows, &c.; nor has there been any complaint of pain in the region of the pelvis, inferior extremities, &c.” (Das SchrÄg Verengte Becken, p. 12.) “With respect to the strength, colour, structure, &c. of the bones of this species of deformed pelvis, no difference could be observed between them and the bones of young and perfectly healthy subjects; not a trace either in form or other respects could be detected of those changes which usually result from rachitis or mollities ossium; and but for this distortion and some other slight irregularities, which required close inspection to detect, these pelves would have been looked upon as well-shaped, and of sufficient capacity.” (NaegelÉ, op. cit. p. 11.) In some specimens no trace of anchylosis at the sacro-iliac symphysis has been observed; but whether this was the case throughout the union of the two bones we cannot say. Professor NaegelÉ is inclined to look upon them as modifications of the pelvis obliquÉ ovata, and certainly in the majority of known cases anchylosis has been found present.

It is scarcely necessary to do more than enumerate other varieties in the form of the pelvis, which are occasionally met with: it is sometimes round, the transverse and antero-posterior diameters being of the same length; in other cases it possesses many of the characters which distinguish the male pelvis, being more or less triangular, deep, and with a contracted angular pubic arch.

Exostosis. Lastly, the pelvis may be perfectly well formed, but the passage through it more or less interrupted by the exostosis: this is, perhaps, the rarest species of dystocia pelvica. It may arise from wounds of the periosteum, from fracture of the bones, callus, &c. and may vary in size from a small protuberance to a large mass, which completely fills up the pelvis.

Diagnosis of contracted pelvis. The difficulty of detecting an abnormal configuration of the pelvis, will depend, in great measure, upon its extent: where it is but slight, it may easily be passed over unobserved by a young practitioner, although it may, nevertheless, be quite sufficient to render labour both difficult and dangerous. In the ordinary form of contracted pelvis, where the antero-posterior diameter is shorter than natural, the being able to reach the projecting promontory of the sacrum with the finger is of itself a sufficient evidence: but the converse of this is not true, for we frequently meet with cases of contracted pelvis, without being able to reach the promontory. The numerous instruments which have been invented at different times for measuring the pelvis are of such doubtful accuracy, as to be nearly useless; the experienced finger is the best pelvimeter; and the power of correctly estimating the dimensions of the pelvis during examination, can only be acquired by constant practice, based on a thorough knowledge of them in the healthy pelvis.

The manner in which labour commences is frequently sufficient to make us suspect the presence of a contracted pelvis. Besides, the general appearance of the patient, we frequently find that the uterine contractions are very irregular; that they have but little effect in dilating the os uteri; the head does not descend against it, but remains high up; it shows no disposition to enter the pelvic cavity, and rests upon the symphysis pubis, against which it presses very forcibly, being pushed forwards by the promontory of the sacrum. It is probably from this circumstance that the os uteri, more especially its anterior lip, shows so little disposition to dilate in these cases, for the lower portion of the uterus being jammed between the head and symphysis pubis in front, and promontory behind, the contractions of the longitudinal fibres can have little effect upon the os uteri. Hence we find, that in cases of diminished antero-posterior diameter requiring perforation, and where the os uteri in spite of violent pains, bleeding, &c. has refused to dilate beyond a certain point, on lessening the head, and thus removing its pressure from the symphysis pubis, it has quickly attained its full degree of dilatation.

Where the pains have been active, and a portion of the head has forced itself through the brim, and now projects to a certain extent into the cavity of the pelvis, it will be still more difficult to reach the promontory before delivery; and if, as is frequently the case, the sacrum is bent strongly backwards, so as to render the cavity and outlet very spacious, the real cause of impediment to the progress of labour may be entirely overlooked. It is here that the position of the head upon the symphysis pubis will prove a valuable means of diagnosis. The straightness of the sacrum will also be a guide in other cases.

In that form of the pelvis which has been called the funnel-shaped pelvis, and where the brim and upper portion of the cavity are of the natural dimensions, but where it gradually diminishes towards the outlet, the appearances are frequently very deceptive, the head advances without impediment, and descends as far as the inferior aperture, with every promise of speedy delivery; but here its progress is arrested, and even in the very last stage may require perforation.

It occasionally happens, also, where the deformity is very considerable, that the promonotory projects to such an extent as to be even capable of being mistaken for the head itself; and cases have actually occurred where, under this impression, the bone has been perforated instead of the child’s head. So gross an error as this may easily be avoided by care in making the examination; by ascertaining that the projecting mass is immoveable; that the patient is sensible to the pressure of our finger; and that the promontory can be traced to be continuous with the adjacent parts of the pelvis.

The effects which may result from labour protracted by pelvic deformity are very various, both as regards the mother and her child. The most common form of injury which is produced by this cause, is the contusion and consequent inflammation and sloughing of the soft tissues which line the pelvis from the long continued pressure of the head against the symphysis pubis in front, and against the promontory of the sacrum behind. Not only may sloughing of the vagina and lower part of the uterus be the result, but the mischief may extend through the posterior wall of the bladder, and thus render the patient incapable of retaining her urine, and an object of great, and, generally speaking, incurable suffering.

The danger from rupture of the uterus will chiefly depend on the degree of pressure with which the uterine contractions force the head against the brim. Where the pains are violent, and yet insufficient to overcome the obstacle which the contracted pelvis presents to the advance of the head, there is not safety for a minute, and perforation must be immediately had recourse to. Where the edge of the promontory is very projecting and sharp, the structure of the uterus may be seriously injured by the pressure and contusion. In some cases it has evidently been the cause of ruptures, the fibres having given way first at this spot.

The constant severe pressure upon the head will be not less injurious to the child’s life; it must inevitably produce a considerable impediment to the cerebral circulation; and where the liquor amnii has escaped, the pressure of the uterus upon the body of the child will scarcely be less prejudicial. The cranial bones frequently become remarkably distorted, so that after a difficult labour a deep furrow is found on that part of the head which corresponded to the projecting promontory.

Fracture of the parietal bone may even be produced, a fact of which practitioners, till lately, have not been sufficiently aware; and cases have occurred where children have been born dead, with the head greatly distorted, and one of the bones fractured, from which circumstances the mothers have been suspected of infanticide. Dr. Michaelis, of Kiel, has lately reported an interesting case of this kind, where the fracture seems to have resulted from the great immobility of the coccyx. The head was much disfigured, and on examining it the frontal bones were uninjured, but so flattened that the frontal and parietal portions of the sagittal suture lay nearly in the same place; the fontanelle and anterior two-thirds of the sagittal suture projected high up, and the sagittal borders of the parietal bones were firm and well formed. In the posterior third of the sagittal suture, where the parietal bones were firm and well formed, and the suture only two lines in width, were seen small livid portions of the longitudinal sinus forced between the bones. The occipital bone was flattened and forced deep under the parietal bones, but not otherwise injured. The right parietal bone, which during birth had been turned towards the promontory of the sacrum, was covered anteriorly and superiorly with effused blood, and on removing the periosteum, was found fractured in five places. (Neue Zeitschrift fÜr Geburtskunde, vol. iv. part 3. 1836.[124])

Where the action of the uterus is not very violent, and the bones yielding, the head gradually adapts itself to the form of the passage without destroying the foetus; it elongates itself more and more until it is enabled to pass, so that after a tedious labour of this sort, we sometimes find the configuration of the head remarkably altered. Baudelocque, has mentioned a case recorded by Solayres de Renhac, where the head was so elongated that the long diameter measured eight inches all but two lines, the transverse being only two inches and five or six lines.

Treatment. Where the pelvic deformity is very considerable, there can be little difficulty in deciding upon the line of conduct to be adopted. It is in those cases where the obstruction is but slight that the indications for treatment are less distinctly marked: nor must we be satisfied with merely ascertaining the relative proportions of the head and pelvis; for the hardness or softness of the cranial bones, the disposition which they manifest to yield to the pressure of the uterus and surrounding parts, the state of the cranial integuments, and though last not least, of the soft tissues which line the pelvis, must all be carefully ascertained before a correct opinion as to the precise mode of treatment can be formed. Nor, if the woman has already had children, can we altogether be guided by the history of her previous labours; for where the above-mentioned circumstances have been favourable, a slight diminution of the pelvis will scarcely be attended with any perceptible delay or increase of difficulty beyond the natural degree; whereas, if the head happens this time to be a little larger, its bones more ossified, the fontanelles smaller, the scalp and soft linings of the pelvis more swollen, &c. a serious obstruction to the progress of labour will be the result. Thus it is that we not unfrequently meet with patients in whom the first labour has been tolerably easy, the second has been attended with much difficulty and required the forceps, in the third, the difficulty was so much increased as to require perforation, and the fourth where the labour was, like the first, perfectly easy and natural.

It is impossible for the head to remain long in the pelvis (except under unusually favourable circumstances) without more or less obstruction to the circulation, both in the scalp itself and in the surrounding soft tissues. The necessary consequence of this is swelling, by which the head increases while the passage diminishes in size; and this must still be more remarkably the case where the pelvis is at all contracted. It is in these cases that we frequently see such relief produced by venesection; and it is also as a topical depletion to the overloaded vessels, that we can explain why a free secretion of mucus is so favourable a symptom.[125]

Prognosis. Where the pains are moderate and equable, the os uteri nearly or quite dilated, the head not large, its bones yielding and overlapping at the sutures; where the greater portion of it has evidently passed through the brim, and, although slowly, advances perceptibly with the pains; where the passages are cool and moist, the pulse good, and the patient not exhausted, we may safely wait awhile and trust to the efforts of nature. On the other hand, where the pains are violent, the os uteri thin and undilatable, the head forced forwards upon the symphysis pubis by the projecting serum, if the greater part of its bulk has not yet passed the brim, if the soft parts are much swelled, the vagina hot and dry, the pulse has become irritable, the abdomen tender, the patient exhausted and much depressed both in mind and body, the powers of nature are evidently incompetent to the struggle, and require the assistance of art.

Such cases seldom permit the application of the forceps; the head is already pressing too firmly against the brim, and its greatest bulk having not yet passed, a still farther increase of pressure will be required to effect this object, which therefore cannot be attained without producing serious mischief. Where, however, the head has fairly engaged in the cavity of the pelvis, and the case is rather becoming one of deficient power, the forceps will be justifiable, and generally quite sufficient to effect the delivery safely.

The young practitioner must be cautious not to mistake an increase in the swelling of the scalp for an actual advance of the head itself—an error which may very easily be committed if he merely touches the middle of the presenting portion: he must carefully examine the circumference of the presenting part, where the head is pressing against the pelvis, and where there is little or no swelling, and he will frequently find to his disappointment, that although the cranial swelling may have even nearly approached the perineum since his last examination, the head itself has remained unmoved.

Where the forceps has been determined upon, we should endeavour to render its action as favourable as possible, viz. by bleeding, by the warm bath, and by evacuating the bladder and rectum before proceeding to the operation: we thus improve the condition of the soft parts, and diminish the chances of its acting injuriously.

From what has now been stated respecting the various circumstances which may tend to aggravate or alleviate the existing degree of pelvic deformity, it will be seen how incorrect and unpractical must be the attempt to classify the means of treatment merely according to the dimensions of the pelvis. To assert that within certain limits of pelvic contraction the child can be delivered by the natural powers, and that beyond these limits the forceps must be used; and that where it proceeds to a certain extent farther, it can only be delivered by perforation, &c. is evidently objectionable: for there are no two cases alike, even supposing that the degree of pelvic contraction is exactly similar; hence, on the one hand, we might (under such fallacious guidance) be induced to trust to the natural powers when they are wholly incompetent to the task, and on the other, to have recourse to art when the real condition of the case justified no such interference.[126]

With regard to the diagnosis and treatment in the case of obliquely distorted pelvis (pelvis obliquÉ ovata,) our data are still too scanty to enable us to give any decided rules: the immobility of the head, although the antero-posterior diameter appears of its full length, the shortness of one oblique diameter, and consequent undue pressure upon the head in this direction, and the unusual length of the other, are the characteristics which we have observed in the only case of the kind which has come under our notice during life. In all the cases of labour rendered difficult by this condition of the pelvis, which have been collected by Professor NaegelÉ, the perforation has been strongly indicated; and where the forceps has been used, it has either failed, as with us, or if the delivery has been effected by this means, it has been attended with fatal consequences.

In exostosis of the pelvis we must be guided by our knowledge of the healthy pelvis, and by our carefully ascertaining the form and size of the bony growth, and in what degree it is likely to impede the passage of the child. As in cases of simple projection of the promontory, the head may be capable of passing, but in doing so becomes more or less distorted: thus Dr. Burns quotes a case from Dr. Campbell, where from exostosis within the pelvis, the left frontal bone was so greatly sunk in, as to make the eye protrude. Professor Otto, of Breslau, mentions a woman who had pelvic exostosis being the mother of four children, in each of whom a small portion of the cranium was depressed and not ossified.

An interesting case has been described by Dr. Kyll, of Cologne, where the patient was the mother of seven children; her former labours had been perfectly natural, except that in the last there had been preternatural adhesion of the placenta, which had required to be removed by the hand; in six days after she was seized with feverish symptoms and violent pain at the spot where the placenta had been attached. The attack yielded to proper treatment, but she continued feverish at night with perspirations, frequently deranged bowels, difficulty in passing water, and severe pain in the abdomen, especially when she tried to stand on the right leg. An abscess formed in the right groin, which was opened and discharged a large quantity of pus, from which her recovery was very slow, and in three years afterwards she became again pregnant. When labour came on, no presenting part could be reached; after a long time the feet came down one after the other, but the nates would not advance. Dr. Kyll found the child resting with the hips on the brim of the pelvis, and completely wedged fast by a hard immoveable tumour as large as a hen’s egg, springing from the upper part of the right sacro-iliac symphysis, and apparently having been a result of the pelvic abscess; the child was delivered with great difficulty by embryotomy.

Perhaps the most remarkable case of pelvic exostosis is that which has been described by Dr. Haber of Carlsruhe, and where also the cause was ascertained to have arisen from a violent fall on the ice when carrying a heavy load upon the head; on coming to herself the woman found that she was unable to move, and in this state was conveyed home; she recovered to all appearances in a few weeks, married, and soon became pregnant. When labour came on it was found impossible to deliver her, from the pelvis being entirely filled with a huge exostosis: the CÆsarean section was performed, but she died, and on examination after death an immense mass of bony growth was found springing from the sacrum, which had been apparently fractured, not only filling up the whole cavity of the pelvis, but arising to a considerable extent above the brim.

In those cases of funnel-shaped pelvis which we have had the opportunity of observing, perforation has been ultimately required, although the head had passed easily through the brim and entered the cavity; in one of these we have subsequently used the artificial premature labour with success.

We have already stated the doubtful utility of arranging cases of deformed pelvis according to their degree of contraction, and of classifying the different modes of treatment by such a scale; still, however, there must be certain limits beyond which it will be impossible to make the child pass, even when diminished by embryotomy. To draw the precise line of demarcation, however, will be nearly if not quite impossible; and, as in cases of slighter deformity, we must take many other circumstances into consideration which we have already mentioned. An inch and a half from pubes to sacrum has been mentioned by many as the extreme degree of contraction through which a full grown child can be delivered by embryulcia; generally, however, in these cases of unusually deformed pelvis, there is much more space on each of the sacrum; and on this, in great measure, will depend the possibility of effecting the delivery. The celebrated case of Elizabeth Sherwood, which Dr. Osborn has recorded, and where he succeeded in delivering the child, although the antero-posterior diameter “could not exceed three-quarters of an inch,” has been looked upon as being of doubtful accuracy, and that Dr. Osborn had unintentionally deceived himself. When, however, we learn that on the right side of the sacrum the antero-posterior diameter was an inch and three-quarters, the incredible nature of the case diminishes considerably, the more as the patient was examined by Dr. Denman and others who fully coincided with Dr. Osborn’s statements. To assert that in this case the antero-posterior diameter was only three-quarters of an inch, as many have done, is evidently incorrect, and tends to throw doubt upon it: the case was evidently the closest possible approach to the limits requiring the CÆsarean operation; its success was mainly attributable to the gradual manner in which it was performed; the child had become completely soft and flaccid from putrefaction, and was thus more capable of being moulded to the contracted passage.