A System of Midwifery Part 1

A System of Midwifery.

by Edward Rigby.

PREFACE.

This System of Midwifery, complete in itself, was published in London, as a part of Dr. Tweedie's "_Library of Medicine_." The first series of the Library, that on "_Practical Medicine_," recently completed, has been received with extraordinary favour on both sides of the Atlantic, and the character of the publication is fully sustained in the present contribution by Dr. Rigby, and will secure for it additional patronage.

The late Professor Dewees, into whose hands this volume was placed, a few weeks before his death, in returning it, expressed the most favourable opinion of its merits; and the judgment of such high authority renders it supererogatory to add a word farther of commendation.

It is only necessary for the editor to say that the production of the author is so complete as to have rendered his labour a light one. He has restricted himself mainly to such additions and references as he conceived would render the work more useful to American pract.i.tioners. The object of the publication being to present the most condensed view of each subject, he believed it to be inexpedient to depart from the plan by making extensive additions, and entering into the discussion of controversial points, most of which are of minor practical importance.

INTRODUCTION.

By the term Midwifery is understood the knowledge and art of treating a woman and her child during her pregnancy, labour, and the puerperal state.

We employ it in this extended sense, because most systematic writers of later times have adopted this arrangement. The terms, _Art des Accouchemens_ of the French, the _Ostetricia_, and _Arte della Parteria_, of the Italians and Spaniards, and the _Geburtshulfe_ of the Germans, are restricted to the process of parturition, although they have been and continue to be, used in the same extended sense as that in which we propose to use the term Midwifery.

Although pregnancy and parturition, strictly speaking, are perfectly natural functions, yet they involve such a complication and variety of other processes, and also changes of such extent, that the whole system is rendered more or less subservient to them during the periods of their existence: hence, therefore, their number and variety must ever render them more or less liable to deviations and irregularities of action, which will necessarily be aggravated by the effects of civilized life, and in many instances are productive of derangement in the general economy of the system. Under such circ.u.mstances the irritability of the system increases at the expense of its strength and vigour, and not only increases its liability to these derangements, but diminishes its power of resisting their effects.

In order that we may render the nature and treatment of the changes and phenomena, which take place in the human system during the periods above alluded to, more intelligible, we shall take a short anatomico-physiological view of the structure, form, arrangement, and function of the parts and organs which are more or less directly concerned in these important processes. This will embrace the subject of embryology, a department of physiological knowledge, which, though it has lately been much enriched by valuable discoveries, still affords a rich field of investigation and research.

The diagnosis and course of healthy pregnancy, and its various diseases, terminating with the subject of healthy parturition and its treatment will form the subject of the succeeding part.

Parturition properly speaking, will come under two separate heads _eutocia_ and _dystocia_; the one signifying natural or favourable labour, the other, unnatural, faulty, or unfavourable labour.

The concluding part will contain a short account of some of the more important diseases which occur to the female during the first month after parturition.

PART I.

THE ANATOMY AND PHYSIOLOGY OF UTERO-GESTATION.

CHAPTER I.

THE PELVIS.

_Ossa innominata.--Sacrum.--Coccyx.--Distinction between the male and female pelvis.--Diameters of the pelvis.--Pelvis before p.u.b.erty.-- Axes.--Inclination._

The Pelvis, as the frame-work which, in great measure, contains, supports, and protects, the complicated apparatus of the generative organs, first claims our attention; since an accurate knowledge of the form, size, and uses, of its different parts is indispensably necessary, not only to understand the situation of the viscera it contains, but also to form a correct view of the mechanism upon which the process of parturition depends.

This osseous ca.n.a.l or circular archway, consists essentially of three bones, the right and left os innominatum, which form the sides of the arch, with the sacrum between them, acting as a keystone, and supporting the whole weight of the trunk above.

_Ossa innominata._ The ossa innominata in early life consists of three distinct bones, the _iliac_ or _hip bones_ at the sides, the _ischia_ or lower portion upon which we sit, and the _ossa pubis_ which meet each other anteriorly to form the front part of the pelvis. In the adult these are consolidated into one bone, merely leaving irregular lines and ridges here and there to mark their previous existence.

These bones present several striking points of resemblance with those which belong to the upper extremities, viz. the scapula and clavicle; and in the early stages of development, this similarity is much more distinctly seen: it is remarkable, that although the ischia and ossa pubis are formed later than the ilia, yet they unite with each other much sooner than with the ilia, so that the two consolidated bones bear the same relation to the ilium which is separated from them, that the clavicle does to the scapula: many other points of resemblance between the bones of the shoulder and pelvis might be noticed if necessary. (Meckel, _Anat._ vol.

ii. p. 239.) The ossa innominata meet each other in front, forming the _symphysis pubis_, having layers of fibro-cartilage interposed between their extremities, and bound together by ligamentous fibres const.i.tuting the _ligamentum arcuatum_, or _annulare ossium pubis_, and by which a more rounded appearance is given to the pubic arch. They are united to the sacrum posteriorly, one on each side of it, forming the _right and left sacro-iliac symphysis_ or _synchondrosis_; this differs in many respects from the symphysis pubis, the cartilaginous coverings of the opposing bones being much thinner, especially those of the ossa innominata; the surfaces are extremely uneven from the deep indentations which each bone presents at this part, locking, as it were, into each other, and thus contributing greatly to increase the firmness of the joint, which is also still farther strengthened by the support of powerful ligaments.

Between the ligamento-and cartilaginous layers which cover the surfaces of the bones at the pubic and sacro-iliac symphyses, a minute collection of synovial fluid may be detected, like that found in the fibro-cartilages between the vertebrae; it serves to lubricate their surfaces, and separates them more or less, thereby increasing the thickness of the intervening cartilaginous structure; and separating also the edges of the bones, to a certain extent, more especially at the symphysis pubis. (Portal, _Anat.

Med._) These laminae of intervening fibro-cartilage are thicker in the female than in the male, although of smaller extent; and this is still more remarkable during pregnancy, this ligamento-cartilaginous structure becoming now more cushiony and elastic, while in the latter months we can easily distinguish blood-vessels ramifying through it, which are branches of the pudic arteries and veins.

_Sacrum._ The sacrum, which forms the upper and posterior portion of the pelvis, contributes greatly to the general solidity of the whole bony circle. From its wedge-like shape, it is admirably adapted to support the entire weight of the trunk, and acts, as we have before observed, as a kind of keystone to the arch which is formed by the ossa innominata. It is of a triangular shape, being concave before and convex behind. In the foetus it consists of five distinct pieces of bone separated by intervening layers of cartilage, like the vertebrae of the spinal column, and from their resemblance to those bones they have been called false vertebrae. These cartilages, after a time, gradually disappear; bony matter is deposited in their place; so that by the period of p.u.b.erty the five sacral vertebrae become united into one solid bone, although they may be distinguished, until an advanced period of life, by the ridges which their edges form.

The upper surface of the sacrum, having to sustain the whole weight of the spinal column, is broad and flat, and corresponds to the lower surface of the last lumbar vertebra. Its anterior surface forms with that of the other mentioned bone a considerable angle, which projects forwards and more or less downwards towards the symphysis pubis, and is called the _promontory of the sacrum_. Beneath this point, the sacrum takes a considerable sweep backwards as it descends, gradually advancing again forwards, as we approach its inferior extremity, forming an extensive concavity upon its anterior surface: this is termed _the hollow of the sacrum_.

_Coccyx._ The lower end is prolonged by a small bone, called _Coccyx_ or _os Coccygis_, from its supposed resemblance to a cuckoo's beak. It usually consists of four, and sometimes (especially in women) of five portions; they are much smaller than the bones of the sacrum, and are very imperfect rudiments of vertebral formation; like these, they are at an early period little else than cartilage, and even when the bones are fully formed, they are united by intermediate cartilage, and thus retain so much mobility upon each other, as well as upon the lower end of the sacrum, as to admit of being forced backwards to the extent of a full inch, thus contributing greatly to increase the capacity of the outlet.

The sacrum not only serves to form the posterior parietes of the pelvis, but by the curve which its lower portion takes forwards, together with the coccyx, it gives a powerful support to the pelvic viscera.

When we take a general view of the bones which collectively form the pelvis, we find that it is evidently divided into two portions--an upper and a lower one. On the Continent these have been called the large and the small pelvis; in Britain we merely speak of the pelvis above or below the _brim_, the line of demarcation being the linea ilio-pectinea at the sides, the crista of the os pubis in front, and the promontory of the sacrum behind. The alae of the ilia form a prominent feature in the upper pelvis, and not only afford an attachment for numerous muscles, but furnish a powerful and ample means of protection and support to the pelvic and lower abdominal viscera. In the female pelvis this is remarkably the case, the cavitas iliaca being well expanded and of greater extent than in the male, the crista of the ilium thrown more outwards; hence the distance between the antero-superior processes is much more considerable.

_Distinction between the male and female pelvis._ At the brim, the female pelvis presents several well-marked points of distinction from that of the male. The male pelvis has a contracted brim of a rounded or rather triangular form, with the promontory of the sacrum considerably projecting; whereas, that of the female is s.p.a.cious, of an oval shape, and with a slightly prominent sacrum, thus affording more room for the pa.s.sage of the child through the brim. The cavity of the male pelvis is deep, while in the female pelvis it is shallow, a circ.u.mstance which is very strikingly seen in comparing the length of the symphysis pubis in each, that of the male pelvis being nearly double the length of the female. This is an important point of difference as regards parturition, because in a shallow pelvis, the extent of surface exposed to the pressure of the head will be much less than where it is deep, and hence the resistance to the pa.s.sage of the child will be proportionably diminished: in confirmation of this, we find that tall women, in whom the pelvis is usually deep, do not, on the whole, bear children so easily as women of middling stature in whom the pelvis is more shallow. The capacious hollow of the sacrum in the female pelvis adds also greatly to the extent of its cavity, and peculiarly adapts it for parturition, the injurious pressure of the head upon the soft linings of the pelvis being thus prevented, and every facility afforded for its quick and easy transit through the cavity. This applies especially to the neck of the bladder, which would almost inevitably suffer in every labour, were it not for the ample hollow of the sacrum relieving the pressure of the head against the anterior portions of the pelvis. The bones of the female pelvis being more slender and delicately formed, the foramina ovalia and sacro-ischiatic notches are wider, and thus add still farther to the capacity of the cavity.

In no part of the pelvis is the difference between the s.e.xes more strongly marked than at the outlet. The s.p.a.cious and well-rounded arch of the p.u.b.es in the female of the slender rami, is a striking contrast to the contracted angular arch of the male pelvis; and the tuberosities of the ischium being much wider apart, the head is enabled to pa.s.s under the arch with greater facility, and thus still farther to relieve the anterior of the pelvis from its pressure. The length of the sacro-sciatic ligaments, and the mobility of the coccyx upon the sacrum, by which it can be forced backwards to the extent of an inch by the pressure of the head during labour, not merely serve to distinguish it from the male pelvis, but afford a beautiful instance of design and adaptation.

The greater width of the pubic arch in the female pelvis is seen by comparing its angle with that of the arch in the male pelvis. In the female it has been estimated to form an angle varying between 90 and 100, whereas in the male it is not more than between 70 and 80.

(Osiander, _Handbuch der Embindungs-kunst_, cap. iv. p. 58.)

From the greater width of the female pelvis, the acetubula are farther apart, and the great trochanters of the thigh-bones more projecting; hence the greater motion of the hips in the female when she walks, which is still more visible when she runs, for the motion is communicated to the whole trunk, so that each shoulder is turned more or less forwards as the corresponding foot is advanced. The thigh-bones, which are so far apart at their upper extremities, approach each other at the knees, contributing to produce that unsteady gait which is peculiar to the s.e.x. "The woman," says Mr. John Bell, "even of the most beautiful form, walks with a delicacy and feebleness which we come to acknowledge as a beauty in the weaker s.e.x."

(_Bell's Anat._ vol. i.)

These characteristic marks of the female figure, upon which its beauty in great measure depends, are well seen in all great works of art, whether of sculpture or painting. "The ancients," as Mr. Abernethy has observed, "who had a clear and strong perception of whatever is beautiful or useful in the human figure, and who, perhaps, delicately exaggerated beauty to render it more striking, have represented Venus as measuring one-third more across the hips than the shoulders, whilst, in Apollo, they have reversed these measurements." (_Physiological Lectures._)

_Diameters of the pelvis._ It is of the utmost importance to the obstetrician, that he should be thoroughly acquainted with the various dimensions of the female pelvis, for, without this, he can form no correct idea of the manner in which the presenting part of the child pa.s.ses through its brim, cavity and outlet during labour; indeed, unless he be thoroughly versed in this necessary point of obstetric knowledge, he will remain in almost total ignorance of the whole mechanism of parturition, which must, in great measure, be looked upon as the basis of practical midwifery. The dimensions of the brim cavity and outlet of the pelvis may be given with sufficient correctness for all practical purposes, by measuring three of their diameters,--1. the _straight_, _antero-posterior_, or _conjugate_; 2. the _transverse_; and 3. the _oblique_. At the brim they are as follow:--the straight diameter, drawn from the middle of the promontorium sacri to the upper edge of the symphisis pubis, 43 inches; the transverse diameter, from the middle of the linea-ilio-pectinea of one ilium to that of the other, 54 inches; and the oblique diameter, from one sacro-iliac synchondrosis to the opposite acetabulum, 48 inches. The oblique diameters are called right and left, according to the sacro-iliac symphysis from which they are drawn.

[Ill.u.s.tration: _Fig. 1. Fig. 2._

In the annexed representations of the superior and inferior aspects of the female pelvis are shown the three diameters of its brim and outlet; those of the former in _fig. 1._, and those of the latter in _fig. 2._ The same letters of reference are used in each figure to indicate the several diameters; thus _a p_ refers to the antero-posterior, _t t_ to the transverse, _o o_ to the right oblique, and _o' o'_ to the left oblique diameters.

In _fig. 2._ the coccyx is represented in situ.]

In the cavity these dimensions vary more or less. The straight diameter, measured from the centre of the hollow of the sacrum to that of the symphysis pubis, is 48 inches; the transverse, from the point corresponding to the lower margin of the acetabulum on one side to that of the other, 43; and the oblique, drawn from the centre of the free s.p.a.ce formed by the sacro-ischiatic notch and ligaments on one side of the foramen ovale of the other, 52.

At the inferior aperture or outlet the alteration is still more remarkable. The straight diameter, from the point of the coccyx to the lower edge of the symphysis pubis, measures only 38 inches; but from the mobility of the coccyx enabling it to be pushed back during labour to the extent of a whole inch, it is capable of being extended to 48 inches. The transverse diameter from one tuberosity of the ischium to the other, measures 43 inches: and the oblique, from the middle of the lower edge of the sacro-sciatic ligament of one side, to the point of union between the ischium and descending ramus of the p.u.b.es on the other 48 inches.

Although these are the proportions of the brim cavity and outlet of the female pelvis in the skeleton state, their real dimensions during life, when the pelvis is thickly lined with muscular and other structures, are very different. The large ma.s.ses of the psoas magnus and iliacus internus, besides other muscles of inferior size, contribute to alter materially the relations of the pelvic diameters to each other; hence we find that, so far from being the longest, the transverse diameter is one of the shortest, being little more than the antero-posterior. This holds good, especially during labour, because these muscles being thrown into powerful contraction, their bellies swell, and thus tend still farther to diminish its length. The oblique diameters are, in fact, the longest during life, because not only are the parietes of the pelvis at the brim covered by a very thin layer of soft tissues in these directions; but as the extremities of these diameters, in the cavity and outlet, correspond to free s.p.a.ces which are merely filled up with soft yielding structure, it follows that their length can be somewhat increased when pressure is applied in these directions; the antero-posterior diameter of the outlet can alone be compared with the oblique diameters in this respect, and then only when the coccyx is forced backwards to its full extent by the pressure of the head.

_Pelvis before p.u.b.erty._ The proportions of the adult female pelvis are no longer what they were during childhood; before the age of p.u.b.erty they resemble those of the male pelvis, the brim being contracted and more or less triangular, and the antero-posterior diameter equalling or even exceeding the transverse. Indeed, at a still earlier period, it presents many points of resemblance even to the pelvis of animals; as, however, growth and development advance, and the various changes which const.i.tute p.u.b.erty take place, the transverse diameters of the brim, cavity, and outlet increase at the expense of the antero-posterior, until at length, it has a.s.sumed the proper proportions of the adult female pelvis.