A textbook of obstetrics . side to side. Bythe pull of the strongsacro-iliac ligaments run-ning from the sacrum tothe. posterior superior spi-nous processes of the iliacbones the latter are pulleddownward and forward bythe descent of the sacralpromontory, and are con-sequently made to ap-proach one another behind,but they do not keep pacewith the movements of thesacrum, and consequentlyproject more prominentlythan common on eitherside. The natural resultof this movement forwardand inward on the part ofthe posterior superior por-tions of the ilia would beto throw the anterior halfof tile innomi
A textbook of obstetrics . side to side. Bythe pull of the strongsacro-iliac ligaments run-ning from the sacrum tothe. posterior superior spi-nous processes of the iliacbones the latter are pulleddownward and forward bythe descent of the sacralpromontory, and are con-sequently made to ap-proach one another behind,but they do not keep pacewith the movements of thesacrum, and consequentlyproject more prominentlythan common on eitherside. The natural resultof this movement forwardand inward on the part ofthe posterior superior por-tions of the ilia would beto throw the anterior halfof tile innominate bones outward, but this movement is opposedby their junction at the symphysis, and to a less degree by theattachment of Pouparts ligament to their anterior superiorspinous processes. The ilia, however, restrained by a somewhatyielding force, are thrown to a certain degree outward and back-ward, .so that their upper edges run almost horizontally outward,and the distance between their anterior spines becomes little less. Fig. 297.—Flat rachitic pelvis withbowed femora: C. v., 5 cm.; tr., 12^ Mtttter Museum, College of Physicians,Philadelphia}. ANOMALIES IN THE FORCES OF LABOR. 443 than, the same as, or even greater than, the distance betweentheir crests. A further result of these combined forces pullingthe innominate bones inward and forward behind and hold-ing them in place in front is to produce in them an abnormalcurvature, as in the case of the sacrum, or as in a bow bentbetween ones hand and the ground (Fig. 298). The point ofangulation or greatest curvature is found on the ilio-pectinealline, back of the median transverse line of the pelvic inlet,near the sacro-iliac joints. On account of the flexion of theinnominate bones the transverse diameter of the rachitic pel-vis is relatively increased, but, as the whole pelvis is com-monly below the normal in size, this diameter rarely exceeds,if, indeed, it equals, the normal transverse measurement. Afurther consequenc
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Keywords: ., bookcentury1800, bookdecade1890, bookidtex, booksubjectobstetrics
