. The science and art of midwifery . ateral movements of the head are not interfered with, it is hardly to be expected that the head, when arrested atthe perineal floor, would continue to maintain a right line with the spine. 174 LABOR. eter, and the childs life, and the soft parts of the mother, are jeopardized. When, however, rotation is completed, the bi-parietal diam-eter (3| inches), which is capable of sustaining a considerable degreeof lateral compression, engages in the transverse diameter of the pel-vis; at the same time the snb-occipito-bregmatic engages in the con-jugate diameter. T
. The science and art of midwifery . ateral movements of the head are not interfered with, it is hardly to be expected that the head, when arrested atthe perineal floor, would continue to maintain a right line with the spine. 174 LABOR. eter, and the childs life, and the soft parts of the mother, are jeopardized. When, however, rotation is completed, the bi-parietal diam-eter (3| inches), which is capable of sustaining a considerable degreeof lateral compression, engages in the transverse diameter of the pel-vis; at the same time the snb-occipito-bregmatic engages in the con-jugate diameter. The latter, though measuring but 3f inches, may beextended to 44- inches by the pressing backward of the tip of the coccyx. The conditions for the forward rotation of the occiput are—1. Flexion; 2. Good labor-pains; 3. A firm perinamm. In either of the occipitoanterior positions rotation is not diffi-cult to understand. The convergent anterior inclined planes furnishsmooth surfaces upon which the occiput glides downward and forward. ii<.. 100.—Figure illustrating the mechanism of labor in occipitoanterior deliveries.(After Schultze.) to the front. The rigid ischial spines direct the forehead to the sacro-sciatic Ligaments, which determine the backward movement corre-sponding to that of the occiput in the front part of the pelvis.* * Prof. Henry Ot. Landis, in a mos< ingenious essay entitled How to use theForceps, argues that, practically, tin- pelvis contains two canals, partially separateat the beginning and identical at their termination. The right canal is the one inwhich the righl sacro-iliac articulation is found, and the left the one to which thehfi sacro-iliac articulation belongs. These canals converge from above down-ward, and are also mutually curved from before backward. Their direction istherefore Bpiral. The caliber of each canal is that of the fetal head: therefore,the head may descend in either canal, and will fellow a spiral course in so doing. MECHANIS
Size: 1863px × 1342px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdec, booksubjectobstetrics, booksubjectwomen
