A textbook of obstetrics . , instead >>i from tin- depression below it. ANOMALIES IN THE FORCES 01 LABOR. 41 ; read off as soon as the pelvimeter is in proper position. It ison the average, in well-built women, 20J^ centimeters. The best measurements for determining the length of theanteroposterior diameter of the pelvic inlet are those taken fromthe lower edge of the symphysis pubis to the promontory of thesacrum,—the diagonal conjugate diameter,—and the distancebetween the upper outer surface of the symphysis pubis and thepromontory of the sacrum. The diagonal conjugate diameteris one
A textbook of obstetrics . , instead >>i from tin- depression below it. ANOMALIES IN THE FORCES 01 LABOR. 41 ; read off as soon as the pelvimeter is in proper position. It ison the average, in well-built women, 20J^ centimeters. The best measurements for determining the length of theanteroposterior diameter of the pelvic inlet are those taken fromthe lower edge of the symphysis pubis to the promontory of thesacrum,—the diagonal conjugate diameter,—and the distancebetween the upper outer surface of the symphysis pubis and thepromontory of the sacrum. The diagonal conjugate diameteris one side of a triangle, the other two sides of which are theheight of the symphysis and the true conjugate. The distancebetween the outer upper surface of the symphysis and the pro-montory of the sacrum differs from the true conjugate by thethickness of the upper portion of the symphysis. Smellie wasaccustomed to estimate roughly the length of the true conjugateby a digital examination, basing his estimate on the ease with. Fig. 259.—Stt-in^ instrument for direct measurement of the conjugate. which the promontory could be reached. In the latter part ofthe eighteenth century Johnson 1 proposed, for estimating thesize of the pelvic inlet, a method which consisted of inserting thefingers of one hand in the mouth of the womb and then spreadingthem between the promontory and the sacrum. A few yearslater the elder Stein devised a graduated rod for measuring thedistance between the lower edge of the symphysis pubis and thedivision between the second and third sacral vertebrae. This dist-tance he believed to be one-half to one inch greater than the trueconjugate. Stein later constructed the instrument for the directmeasurement of the conjugate shown in figure 269. Manx-instruments have since been constructed on this principle, butthey are impracticable in the living female, for obvious was the first to propose the measurement of thediagonal conjugate and the subtr
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Keywords: ., bookcentury1800, bookdecade1890, bookidtex, booksubjectobstetrics
