Colinstein, envisaging the question from the standpoint of compression of the fo3tal head, concludes: 1. The after-coming head passes more readily than the before-coming, since in the former instance there is pro duced a diminution in the ceplialo-rachidian fluid, and, in consequence, a greater overlapping of the sutures, and greater reduction in size of the head. 2. In medium contractions, it passes more readily because its bony walls and the maternal parts are more closely in contact, and this favors accommodation, as well as evacuation of the cerebro-spinal fluid. 3. Still, in case of the after-coining head, the life of the child is more compromised, because, on account of the above occurrence, the brain is more compressed.
And yet Schatz, believing the life of the mother Is of greater value than that of her child, and tractions with the forceps more dangerous for her than the traction on the trunk, resolutely favors version.
Li wenhardt considers version and extraction as the heroic measures in case of pelvic deformity. He maintains that by version we cannot place the head symmetrically. He only succeeded twice in nine attempts, and in five cases he had to use forceps to extract the after-coming head. He is opposed, however, to waiting for spontaneous labor, and prefers the forceps only when: 1. The pelvis is large enough to admit the passage of the child without mutilation. 2. The child is living. 3. The child pre sents by the vertex. But whether for forceps or version, the pelvis must be at least 2.9 inches.
Ile endeavors to explain his preference for forceps by the data, on follow ing page, which, however, are of little value, seeing that the degree of contraction is but vaguely indicated.
Goodell, in two monographs, 1875, 1876, advocates version at term. " If the contraction is slight, he makes one or two attempts with the for ceps. If the head cannot be thus engaged, version must be resorted to. In pelves where the conjugate measures from 2.7 to 3.1 inches version should ever have the preference. To vigorous tractions on the trunk he joins expression. In 10 cases, 4 living children, 2 from primiparce, 2 multi parte, in whom at previous labors, delivery by forceps had been suc cessful. There was always depression of the parietals." Alexander Milne uses version, but combined with induction of prema ture labor. Six women, with pelves ranging from 2.3 to 2.9 inches, had been delivered of 12 children, 11 of whom had died during extraction by forceps or craniotomy. In all the succeeding pregnancies, Milne induced
labor and performed version. In 38 instances he obtained 35 living chil dren, 7 of whom died in infancy, the lot of 11 being unknown, and 17 reached adult ago.
Budin, Rage, and Matthews Duncan, have experimented on the head of the foetus before and at term, in regard to its compressibility, the force which may safely be exerted in traction, and the lesions which may re sult. Champetier de Ribes has lately made new experiments in the same direction, and we may resume his studies and conclusions, as follows: 1. Mechanism of the Descent of the Ilead.—If, in a pelvis con tracted in the conjugate, the head be left at the superior strait after the extraction of the trunk and the shoulders, it assumes ordinarily, a transverse position. The base of the skull, although almost incompressible, may engage, without the influence of much force, in an opening smaller than itself, the posterior portion of the head rest ing on the bodies of the vertebrae above the promontory—the posterior border of the head descending first, instead of last, as it does in case of easy engagement. When the head descends either spontaneously, or in obedience to traction, it flexes, as Budin has pointed out, and the occiput rises. As this flexion occurs, its posterior portion moulds itself on the part of the pelvis in contact with it, and the fronto-parietal suture ap proaches the median line, or else the borders of the parietal or the fron tal bone, which limit this suture. In addition to this flexion and displace ment, the head turns on its axis, so that the occiput is brought in front or behind the corresponding extremity of the transverse diameter of the pelvis. According as the head is large or small, the occiput will rotate backward or forward. The posterior parietal protuberance is stopped be hind above the ala of the promontory. If traction be made, the head is found to incline from behind forward. While the posterior portion re mains motionless, the anterior describes the arc of a circle; the anterior parietal protuberance, which is on a higher level than the posterior, de . scends and passes by the superior strait. The cheek, which has cleared this same strait, is applied closely to the sacral concavity, and the posterior parietal protuberance descends either directly or else along the sacro-iliac synchondrosis. The end of the rotation movement brings the occiput behind the symphysis.