Ithas already been stated that in presentations of the Trunk it is nearly always the right or left shoulder which occupies the passage. It is stated, by some authors, that they have felt the back, and abdomen, but others think they were mistaken; and most certainly such positions are extremely rare, if they actually do ever exist.
There are two presentations of the Trunk, determined by the side on which the fœtus lies, and denominated accordinglyrightorleft lateral presentations.
Each of these presentations has two corresponding positions, determined by the side on which the child's head lies. If the head be on the mother's right side it is called theright cephalo iliac position, and if it be on the left side it is denominated theleft cephalo iliac position. The mechanism of spontaneous delivery is the same in them both, and in all their varieties, and so is the mode of rendering assistance, so that a description of one will suffice.
Sometimes, when the labor has lasted long without assistance, one arm will be forced down first, and even appear externally. This used to be considered a separate presentation, and described as such, under the name ofpresentation of the hand and arm. There is no reason for describing it separately however, and no utility in doing so, as it differs in no essential particular from ordinary presentation of the shoulders, and must receive the same assistance.
What it is that produces presentations of the Trunk, and other unfavorable parts, is not known, though they are generally thought to be owing to excessive motion in the child, or obliquities of the Womb.
M. Lachapelle met withsixty-eightcases of Trunk presentation infifteen thousand six hundred and fifty-two labors, which is nearly the same as the face. The right side presents more frequently than the left, and the head is on the left side oftener than on the right, as it is in ordinary head presentations.
As a general rule assistance is always rendered in presentations of the Trunk, and is generally considered absolutely necessary. It is undoubtedly true however, that nature has effected delivery in such cases unaided, though rarely, and such instances are considered as extremely fortunate exceptions to the general rule. M. Chailly says that the accoucheur should never leave such cases to nature alone, but always aid her; but other authors trust to her a little more. The most usual mode of rendering assistance is toturn the child, and bring down the feet, a manœuvre which will be fully described hereafter.
In some cases the child turns itself, from the contractions of the Womb, before it enters the upper strait; and in other cases, when very small, or long dead, it will pass folded double. This self-turning however, cannot take place after the escape of the waters, so that it seldom occurs when the membranes are broken.
This is the most usual mode for the fœtus to escape,in each presentation, and in every position. By referring to the following Plates, and the accompanying descriptions, it will be readily understood.
PLATE XXXV.left cephalo iliac positionPosition of the Fœtus in a presentation of the right shoulder, and in the left cephalo iliac position.
PLATE XXXV.
PLATE XXXV.
left cephalo iliac position
Position of the Fœtus in a presentation of the right shoulder, and in the left cephalo iliac position.
Position of the Fœtus in a presentation of the right shoulder, and in the left cephalo iliac position.
Previous to the rupture of the membranes the child's body liesacross, as formerly explained; but immediately after the rupture the shoulders descend into the Pelvis, as seen in the above Plate, while the head remains above the pubes; the arm frequently, but not always, protruding externally.
The shoulder then continues to descend, the body following, bent up against the face, as seen in Plate XXXVI.
PLATE XXXVI.Trunk presentationDescent of the shoulder in a Trunk presentation, at a more advanced period.
PLATE XXXVI.
PLATE XXXVI.
Trunk presentation
Descent of the shoulder in a Trunk presentation, at a more advanced period.
Descent of the shoulder in a Trunk presentation, at a more advanced period.
Here the shoulder is protruded from the Vulva, the back being nearly folded, and the knees turned up against the face.
PLATE XXXVII.Descent of the shoulder and trunkDescent of the shoulder and trunk at a still later period.
PLATE XXXVII.
PLATE XXXVII.
Descent of the shoulder and trunk
Descent of the shoulder and trunk at a still later period.
Descent of the shoulder and trunk at a still later period.
The whole Trunk is now fully delivered, folded almost double, and the legs and feet are turned up against the face. They speedily follow however, and then nothing is left but the head, and perhaps one or both arms, placed against the sides of it, as shown in Plate XXXVIII.
PLATE XXXVIII.Trunk fully descendedThe Trunk has fully descended, and only the head is left, with one arm.
PLATE XXXVIII.
PLATE XXXVIII.
Trunk fully descended
The Trunk has fully descended, and only the head is left, with one arm.
The Trunk has fully descended, and only the head is left, with one arm.
The arm is generally very easily brought down, or it may remain and come with the head. The delivery of the head is effected the same as in presentations of the pelvis, and is seldom attended with much difficulty, the parts having been so much distended. The body always rotates so that the back comes in front, and the chin passes into the curve of the Sacrum.
This is the way in which the delivery is effectedby nature in such cases, and it will readily be conceived how dangerous it is to both mother and child, and how seldom it can be accomplished. If the Fœtus be of a full size, and the mother's pelvis no larger than ordinary, it is almost impossible for this spontaneous evolution to take place; and even when it does, it is with the greatest difficulty, the mother suffering in an extreme degree, and running great risk, not only of the most serious after results, but even of death. To the child the danger is equally great, owing to the severe and long-continued compression it receives, and the unnatural position it assumes. M. Velpeau tells us that inone hundred and thirty-sevensuch cases,one hundred and twenty-fiveof the children died. The number of the mothers also, who either died or were made sufferers all their future lives, was undoubtedly great, though unknown.
It is evident therefore, that presentations of the Trunk are the most unfavorable known, and labor in them is but rarely spontaneous. Nature can but very seldom effect the delivery of the Fœtus herself, and even when she does it is with the greatest risk, both to it and the mother. The accoucheur shouldalwaysassist therefore, if he can, because even if nature can complete the delivery it is with such danger. The means of assisting, by turning, will be described in another Chapter.
If the fœtus is not at full term, and of course is under the full size, its expulsion may be left to nature safely, but not otherwise.
SECTION V.THE PHYSIOLOGY OF SPONTANEOUS DELIVERY, OR CHILDBIRTH, AND THE MANNER OF CONDUCTING A NATURAL LABOR.Havingnow completed the description of theMechanism of Delivery, in all the various presentations and positions, it is necessary to explain the physiological phenomena attending a natural labor, and the duties of the accoucheur when conducting it, and to show what assistance he can render, and when he should or should not interfere.
THE PHYSIOLOGY OF SPONTANEOUS DELIVERY, OR CHILDBIRTH, AND THE MANNER OF CONDUCTING A NATURAL LABOR.
Havingnow completed the description of theMechanism of Delivery, in all the various presentations and positions, it is necessary to explain the physiological phenomena attending a natural labor, and the duties of the accoucheur when conducting it, and to show what assistance he can render, and when he should or should not interfere.