A treatise on the science and practice of midwifery . easurements given by variouswriters differ considerably and varysomewhat in different pelves. Tak-ing the average of a large number,the following may be given as thestandard measurements of the femalepelvis: Anteroposterior (in.). Oblique (in.)- Transverse (in.). Brim , Cavity Outlet Differences in Various Parts of Pelvis.—It will be observed that thelengths of the corresponding diameters at different places vary greatly ;thus, while the transverse is longest at the brim, the oblique is longestin the cavity
A treatise on the science and practice of midwifery . easurements given by variouswriters differ considerably and varysomewhat in different pelves. Tak-ing the average of a large number,the following may be given as thestandard measurements of the femalepelvis: Anteroposterior (in.). Oblique (in.)- Transverse (in.). Brim , Cavity Outlet Differences in Various Parts of Pelvis.—It will be observed that thelengths of the corresponding diameters at different places vary greatly ;thus, while the transverse is longest at the brim, the oblique is longestin the cavity and the antero-posterior at the outlet. It will be subse-quently seen that this fact is of great practical importance in studyingthe mechanism of delivery, for the head in its descent through the pelvisalters its position in such a way as to adapt itself to the longest diam-eter of the pelvis; thus, as it passes through the cavity it lies in theoblique diameter, and then rotates so as to be expelled in the antero-posterior diameter of the Transverse Section of Pelvis, showing theDiameters. ANATOMY OF THE PELVIS. 43 Diameters as Altered by Soft Parts.—In thinking of these measure-ments of the pelvis it must not be forgotten that they are taken in thedried bones, and that they are considerably modified during life by thesoft parts. This is especially the case at the brim, where the projectionof the psoas and iliacus muscles lessens the transverse diameter abouthalf an inch, while the antero-posterior diameter of the brim and all thediameters of the cavity are lessened by a quarter of an inch. The rightoblique diameter of the brim is, even in the dried pelvis, found to be onan average slightly longer than the left, probably on account of theincreased development of the right side of the pelvis from the greateruse made of the right leg; but in addition to this the left oblique diam-eter is somewhat lessened during life by the presence of the rectum onthe left side. Th
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectobstetrics, bookyear1
