. The science and art of midwifery . cted to the front. The cartilage of the symphysis pubis generallyprojects inward, the pectineal line is often unusually sharp, and attimes terminates at the insertion of the psoas muscle in a projectingspine. Below, the ischia diverge from one another, and the arch ofthe pubes is widened. The result of these changes is to produce a shallow pelvis, withcontraction at the brim and widening at the outlet, The shape ofthe brim varies between a Long ellipse and that of a heart or different degrees of variation depending upon the extent of thedisplacem
. The science and art of midwifery . cted to the front. The cartilage of the symphysis pubis generallyprojects inward, the pectineal line is often unusually sharp, and attimes terminates at the insertion of the psoas muscle in a projectingspine. Below, the ischia diverge from one another, and the arch ofthe pubes is widened. The result of these changes is to produce a shallow pelvis, withcontraction at the brim and widening at the outlet, The shape ofthe brim varies between a Long ellipse and that of a heart or different degrees of variation depending upon the extent of thedisplacement forward of the promontory. Externally, owing to thehorizontal position of the sacrum, a depression exists in the lumbar re-rion, the sulcus between the nates is broad and superficial, and theanal orifice is exposed to view. To appreciate the rachitic pelvis, it is necessary to bear in mind thechanges wrought by rickets in the bony structures. In the physiolog-ical growth Of the pelvic bones, new cell-elements develop beneath the. 476 THE PATHOLOGY OF LABOR periosteum and adjacent to the cartilaginous borders upon thearticulaisurfaces. These cell-elements promptly ossify, and thus provision ismade for the increase of the bones in extent and thickness. Simulta-neously with the formation of the new hone, medullary spaces are pro-duced in the bony tissues by a process of absorption. Now, in rickets, while the new cell-eleinents are deposited in Such liunihcrs that the preparatory layer is often five t ten times the normal thickness, theprocess of ossification is suspended or imperfectly performed. Thus,the rachitic pelvis consists of a number of more or less linn, bony masses, covered with soft osteoid layers, with broad cartilaginous bor-ders at the articular surfaces. These changes combine to increase thepliability of the pelvis, and to retard its growth. The pelvic deformity resulting from rickets is mainly due to theweight of the superimposed body. The pressure from above w
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Keywords: ., bookcentury1800, bookdec, booksubjectobstetrics, booksubjectwomen
