. An American text-book of obstetrics. For practitioners and students. °, a normal thickness of the symphysis, and a normal height ofthe promontory (Figs. 301-305).These factors, however, are notconstant, and if they vary muchfrom the normal the most skilfuland most experienced obstetricianmay be misled wofully in hisestimation of the true writer has had under his carea rachitic dwarf in whom therewas more than 3 centimeters dif-ference between the diagonal andtrue conjugates, and Pershingfound among 90 pelves in themuseums of Philadelphia a dif-ference varying from centi-met
. An American text-book of obstetrics. For practitioners and students. °, a normal thickness of the symphysis, and a normal height ofthe promontory (Figs. 301-305).These factors, however, are notconstant, and if they vary muchfrom the normal the most skilfuland most experienced obstetricianmay be misled wofully in hisestimation of the true writer has had under his carea rachitic dwarf in whom therewas more than 3 centimeters dif-ference between the diagonal andtrue conjugates, and Pershingfound among 90 pelves in themuseums of Philadelphia a dif-ference varying from centi-meter to centimeters. It is j . , , Fig. 305.—Effect of the lessened slant outward of the Cleclareol that these Sources Ot symphysis in a rachitic pelvis upon the relationship error mav be eliminated bv the between the true and the conjugate diameter (Ribemont- „ Dessaignes). following corrections : For every degree of increase in the conjugato-symphyseal angle add half the number of millimeters to the sum to be subtracted from the diagonal conjugate, and vice. 506 AMERICAN TEXT-BOOK OF OBSTETRICS. versd ; also, for every centimeter increase in the height of the symphysisover the normal add centimeter to the sum to be subtracted from thediagonal conjugate, and vice versd. While these rules are admirable for thestudy of the dried specimen in a museum, they are not easily applied to theliving pregnant female. The height of the symphysis can be measured in theliving subject, but an allowance for variations in this respect eliminates errorin only a small proportion of cases. The variations in the angle of the sym-physis, a much more important source of error, can only be surmised. Thewriter much prefers the measurement between the upper outer edge of thesymphysis pubis and the promontory of the sacrum for the estimation of thetrue conjugate, having demonstrated its superior accuracy in Fortaking this measurement the patient is put in the dorsal position, wi
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectobstetrics, bookyear1
