. Obstetrics: the science and the art. ce will soon teach even ayoung practitioner, that the child retains in early stages of labor theability to rotate its head right or left within the pelvis, and that itgenerally exercises this faculty quite freely, spinning its head uponthe cervical spine, so as to turn the vertex sometimes quite close tothe symphysis pubis, and then whirling it back to the top of theischium, or even as far backwards as the ilio-sacral junction. Asthe cranium, however, plunges deeper and deeper into the excava-tion, it becomes so tight-Fig- 22. Ij lield that these free mot
. Obstetrics: the science and the art. ce will soon teach even ayoung practitioner, that the child retains in early stages of labor theability to rotate its head right or left within the pelvis, and that itgenerally exercises this faculty quite freely, spinning its head uponthe cervical spine, so as to turn the vertex sometimes quite close tothe symphysis pubis, and then whirling it back to the top of theischium, or even as far backwards as the ilio-sacral junction. Asthe cranium, however, plunges deeper and deeper into the excava-tion, it becomes so tight-Fig- 22. Ij lield that these free motions cease, and itonly moves in the direc-tion impressed upon itby the mechanics of thepelvis. 110. The processes bywhich the vertex in alabor of the second po-sition, as in Figure 22,is brought forth, are theconverse of those I havedescribed an taking place in cases of lii-st ]K)siti(m. The flexion isIbllowed by tlic rotation as the head sinks h)w into the cavity; thevertex being repelled towards the left by the inclined plane of the. MECHANICAL IXFLUEXCE OF THE PELVIS. 77 right ischium. As soon as the posterior part of the summit of thehead reaches the perineum, the perineum, while it yields before thedescending power, thrusts the occiput firmly upwards against thecrown of the pubal arch, as in the first position. The extension orretroversion of the head being completed by its expulsion, restitutionthen follows by carrying the vertex to the right acetabulum, outside,and the face to the left thigh. The left shoulder turns to the rightand forward to get under the arch, while the right shoulder goesback to the sacrum, and so the shoulders are delivered; sometimes,however, the pubal shoulder is the first, and sometimes the sacralone is the first to be expelled. 111. Third Position.—The mechanism of the head, when thevertex presents in the third position, differs from the two just beforedescribed, only in the absence of the second act, the act of rotation. 112. These third posit
Size: 1972px × 1268px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1860, booksubjectobstetrics, bookyear1
