. The science and art of midwifery. xtends from the upper border of the symphysis pubis to thepromontory. Its length is four and a quarter inches. About twofifths of an inch below the upper border of the symphysis is situatedthe obstetrical, as distinguished from the anatomical, conjugate. Thelength of the former, owing to the thickening of the pubic bones, isreduced to four inches. The transverse, sometimes termed the bis-iliac, diameter is thewidest distance between the ilia. It measures five and a quarterinches. The oblique diameters extend from the ilio-pectineal eminences tothe opposite s
. The science and art of midwifery. xtends from the upper border of the symphysis pubis to thepromontory. Its length is four and a quarter inches. About twofifths of an inch below the upper border of the symphysis is situatedthe obstetrical, as distinguished from the anatomical, conjugate. Thelength of the former, owing to the thickening of the pubic bones, isreduced to four inches. The transverse, sometimes termed the bis-iliac, diameter is thewidest distance between the ilia. It measures five and a quarterinches. The oblique diameters extend from the ilio-pectineal eminences tothe opposite sacro-iliac articulations. The distance between the points mentioned is five right oblique diameter isthe one directed to the right,and the left to the left sacro-iliac articulation. The axis of the superiorstrait is represented by a linedrawn perpendicular to thecenter of the plane. Theextension of this line fallsbelow upon the extremity ofthe coccyx, and above strikesthe abdomen near the umbil-of the brim is very nearly. Diameters of the outlet. The circumference icus (vide Fig. 98).sixteen inches. The inferior strait proper, or outlet of the pelvis, is bounded bythe sub-pubic ligament, the pubic rami, the rami and tuberosities ofthe ischia, the sciatic ligaments, and the coccyx. Owing to the pro- MECHANISM OF LABOR. 159 jection of the iscliia, the surface of the pelvic outlet is rendered con-vex, or, perhaps, is better described by supposing it to be composedof two obtuse-angled triangles with apices at the symphysis and coccyx,and with a common base formed by a line drawn through the ischia. The antero-posterior diameter extends from the lower border ofthe symphysis to the extremity of the coccyx. It measures three andthree quarters inches, though, when the coccyx is pushed backward,the distance may be extended to four and a half inches. The transverse diameter, between the inner borders of the tuberos-ities, measures four and a quarter inches. COCCYX PUSHED BACK
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Keywords: ., bookcentury1800, bookdecade1890, bookidsci, booksubjectobstetrics
