. Lectures on natural and difficult parturition . h, and sometimeseven diaphanous. In the female pelvis it is more expanded thanin the male, gives a greater breadth to the hips, and, beingsuflSciently conspicuous, it is often taken as an index of theproportion of the pelvis itself; here, however, an error may bevery readily committed, inasmuch as the cavity may be narrow,and yet the alae of the pelvis very much apart. This greaterbreadth is obviously very advantageous, when the increasinguterus begins to occupy the abdominal cavity. In the wellformed pelvis, the distance from one antero-superi
. Lectures on natural and difficult parturition . h, and sometimeseven diaphanous. In the female pelvis it is more expanded thanin the male, gives a greater breadth to the hips, and, beingsuflSciently conspicuous, it is often taken as an index of theproportion of the pelvis itself; here, however, an error may bevery readily committed, inasmuch as the cavity may be narrow,and yet the alae of the pelvis very much apart. This greaterbreadth is obviously very advantageous, when the increasinguterus begins to occupy the abdominal cavity. In the wellformed pelvis, the distance from one antero-superior spinousprocess to the opposite is about t^n inches. The inferior portion forms a part of the true pelvic cavity,and principally consists of the ischium. Its internal surface isbounded by the obturator foramen on the one side, and theischiatic foramen on the other : it is smooth, and corresponds tothe acetabulum on the external surface. This surface is called(in obstetric language) the plane of the ischium, because the head POSTERIOR PLANE. 15. Vertical Section of Pelvis, showing the anterior and posterior surface of the plane of the Ischium,— The lines represent the inclined plane of the promontory—plane of the brim—of the cavity—of the outlet. Vide p. 24. of the child glides upon it in its descent, and passes forwardunder the arch of the pubis; but if carefully examined, it willbe found to consist of two planes very slightly inclined in oppo-site directions, and divided by a line passing from the pectinealeminence to the spine of the ischium. In some pelves, this ismore obvious than in others; but when the soft parts are at-tached, this will be found nearly corresponding to the reflectionsof the peritoneum which form the broad ligaments. Thus, theinternal surface of the ischium before the soft parts are removedpresents two broadly curved surfaces, one anterior, the otherposterior; these greatly contribute to facilitate the rotation ofthe head of the child in passing
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Keywords: ., bookcentury1800, bookdecade1840, bookidlec, booksubjectobstetrics
