Even as in case of version, everything which might be needed should be ready; bath for the infant, laryngeal tube, etc. The bed should be high, resisting, and the instruments within reach of the accoucheur.
Position of the Patient. —If the head is at the vulva, or at the inferior strait, the woman may lie in her bed, pulled to the edge, each leg rest ing on a chair, and flexed by an assistant. But if the head is high up, or we expect trouble, the obstetrical position should be assumed. In England, the woman is placed in the lateral decubitus when the straight and short forceps is used, the dorsal decubitus being reserved for high forceps. We much prefer, in every instance, the dorsal decubitus.
Before introducing the instrument, we must warm it, and grease it on the convex surface so that it may slide well, and we should always, when ever possible, assure ourselves of the exact position of the head—in a word, complete our diagnosis.
The operative manual is in three stages: 1. Introduction of the blades. 2. Locking of the blades. 3. Extraction of the fietus; and special rules are applicable to each stage.
Cazeaux has enumerated these with a master hand, and we follow him in his description; but, as we will see, they are not all of equal importance.
1. The Instrument should only be applied to the festal Head.—This rule is too absolute, for although the forceps is constructed to seize the festal head, we have seen that in breech presentations, Dubois, Depaul, Tar sier, Stoltz, and a number of foreign accoucheurs, have employed the in strument with success in a number of instances. We would make, then, the following general rule: the forceps should only be applied to the head, whether flexed or extended, before-coming or after-coming, or left in the uterus after decapitation. Exceptionally, it may be applied to the breech, when it is to the interest of mother or of child to end labor, and this can not be done by the hand alone.
2. The Blades should be applied as nearly as possible to the Sides of the Head, with the Concavities of the Borders directed towards the Point of the !Lead which we wish to bring under the Symphysis.—This may be called the French, in contradistinction to the foreign method, and we must explain here what is meant by direct and oblique application of the forceps. When the head is in the occipito-pubic; or occipito-sacral posi
tion, and it is seized in its bi-parietal diameter, since this diameter corre sponds to the transverse of the pelvis, the forceps is applied at once sym metrically to the head and to the pelvis—that is to say, the lesser curve of the instrument is under the pubic arch, at the anterior extremity of the antero-posterior diameter of the pelvis, and the greater curve is in the concavity of the sacrum, at the posterior extremity of the same diameter; the convexity of the blades corresponds to the extremity of the transverse diameter of the pelvis, the concavity seizes the head at its bi-parietal di ameter. The forceps is both parallel to the head and to the pelvis; the application is direct.
But the position of the head may be oblique or transverse, and then the application of the forceps is oblique. If the instrument is applied parallel to the head, it is oblique to the pelvis; if it is parallel to the pelvis, the head cannot be seized in its bi-parietal diameter, and the application is oblique to the head. Hence, then, the French and the foreign methods. While in France we always aim to grasp the head in the bi-parietal diam eter, in England, and above all in Germany, the blades are always in serted parallel to the pelvis. In the oblique presentation of the head, whether first, second, third or fourth positions, it is always possible to seize the head in the bi-parietal diameter. The forceps once locked, then, they will be oblique to the pelvic walls, and will cross the vulva obliquely, the lesser curve not towards the symphysis, but to the right or left, ac cording to the case. The same holds for face presentations.
In transverse presentations it is no longer possible to seize the head in the bi-parietal diameter. The head. lying in the transverse diameter of the pelvis, if we endeavor to apply the forceps in the bi-parietal diameter, one of the blades would lie against the sacral curve and the sacro-verte bral angle, the other against the symphysis, and this is practically impos sible, whether with the classic or with Tarnier's forceps. To attain this aim, Uytterhoeven and Baumers gave to their forceps a peculiar curve.