2. Occipito-sacral Position.—The bi-parietal diameter of the head still corresponds to the transverse of the pelvis, and the sides of the head to those of the pelvis, but the occiput lies backward, the forehead anteriorly. Here, also, the forceps are applied directly, left blade to left, and right to right side. We are, therefore, in opposition to the rule which says that the lesser curve of the forceps should be directed towards the part of the head which is to come under the symphysis, that is to say, the occiput; it would be impossible, indeed, to conform to this rule in the present in stance, for we would be obliged to insert the left blade to the right, and the right to the left, and we have seen that the only absolute rule for the forceps is left blade to left, and right to right. [Richardson, of Boston, advocates, in posterior positions, the insertion of the blades inversely to the ordinary way, then bringing down the head to the pelvic floor, re moving the blades, and, if rotation does not occur spontaneously, re-ap plying them in the classic fashion. This manceuvre has answered us well.—Ed.] The forceps then is applied as in the preceding instance, and the lesser curve corresponds to the forehead. The left blade, here as well, had better be introduced first. (See Fig. 95.) When the head has been regularly grasped, the instrument is parallel both to the head and to the pelvis. All that remains is delivery. Here authorities are not in accord. Some are in favor of delivering with the occiput posterior, others counsel artificial rotation in order to bring the occiput under the pubes, and then to re-apply the forceps.
We believe in always attempting rotation. But this attempt should only be made when the head has reached the pelvic floor, and then either rotate, or deliver with the occiput posterior. (Figs. 96 and 97.) At the outset traction must be made downward and backward, in order to bring down the occiput. This is far from easy, and hence various methods.
Hubert (de Louvain) advises placing a firm filet over the pivot, an as sistant pulls by this strongly downward, while the operator makes traction with one hand at the lock, the other holding the handles.
Couzot (de Dinars) presses downward with his knee at the lock, while the hands simply control the handles. Chailly knelt before the bed, placed the handles under his shoulder, the two hands at the lock, and pulled downwards with all his might.
Above all these manoeuvres, more or less violent, we much prefer that of Pajot. (See Fig. 94.) Seize the instrument firmly near the vulva, carry the handles with the other hand at first downward and a little out ward; then, as the head descends more and more, the hand near the vulva endeavors to depress the blades. Finally, when the head reaches the peri neum, depress the handles so as to extend the head. (Fig. 97.) The forehead thus comes behind the symphysis, as the occiput descends along the posterior vaginal wall.
Pajot's method is certainly less violent than the others, but the deliv eryof.the occiput posterior necessarily entails laceration of the perineum, to say nothing of the fact that the head, in passing along the posterior wall of the pelvis, greatly distends it, and exposes it to bruising, which may be of great consequence. Finally the blades may slip, if the head does not
descend, or only with difficulty. Hence, as soon as the head reaches the bottom of the cavity, we proceed no further with Pajot's method, but endeavor to rotate artificially. We only deliver the occiput posteriorly when we are forced to do so, that is to say, when we cannot rotate with the forceps. Often this is possible, but then again not at all so, and then the efforts we make may damage the mother as well as the infant, and we must extract the occiput posterior, even if we do tear the perineum; and this we can limit by lateral incisions. • The method which consists in bringing the occiput forward is not ad mitted by all accoucheurs. Smellie was the first to practise it, and Puzos, Levret, Deleurye, Petit, Astruc, Solayres, Baudelocque, Herbiniaux, Capuron, Moreau, Naegele, Chailly and Cazeaux rejected it. To-day, neither Stoltz, Pajot, Grenser, Hyernaux, Chassagny, Villeneuve nor Sentex, will adopt it. Exceptionally resorted to by P. Dubois and Dan yau, it has become customary with Depaul, Blot, Joulin, Bailly, Tarnier and his pupils, and we are ourselves partisans in its favor. The adversa ries of the method say that it makes the head rotate more than a quarter, while the body is immobilized by the contraction of the uterus, and that hence it exposes the infant to grave lesions in the cervical region, about the atlo-axoid articulation. Although facts are against this protest, Tar nier, from his personal experiences, has routed all the objectors. " From experiments on many cadavers of new-born infants I have proved that when the head is turned one-half the circumference, the shoulders being steadied, the motion does not alone occur at the atlo-axoid joint, but throughout the whole extent of the cervical, and a portion of the dorsal spine, the vertebrae twisting spirally. In order to make the head thus rotate, great force must be used, and yet careful dissection has failed to reveal the slightest lesions in the membranes or the spinal marrow. But, it may be said, if the vertebra are twisted, the spinal cord must be com pressed. To guard against this objection, I substituted for the cord a fluid column, connected with an external glass tube. Every compression of the canal caused the fluid to mount in the tube, and yet torsion of the head did not. Strong flexion of the head did cause it to rise. I am thus convinced that exaggerated rotation compresses the cord less than as great flexion as we are obliged to produce in order to extract the occiput in posterior positions." Ribemont resumed the experiments of Tarnier, and reached the same conclusions. After having frozen a foetus in a position where the chin looked backward and the occiput anteriorly, he made hori zontal sections at different levels of the vertebral column, and vertical sections antero-posteriorly, and his studies of the sections resulted in the following conclusions: 1. As Tarnier has shown, torsion of the neck affects the whole cervical column, and six or seven of the dorsal vertebra.