A treatise on the science and practice of midwifery / By W. S. Playfair.
- William Smoult Playfair
- Date:
- 1885
Licence: Public Domain Mark
Credit: A treatise on the science and practice of midwifery / By W. S. Playfair. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
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![of the sacrum, and averages half an inch more than the antero-posterior diameter of the brim. These measurements are chiefly of importance in relation to certain pelvic deformities. External Measurements.—The external measurements of the pelvis are of no real consequence in normal parturition, but they may help us, in certain cases, to estimate the existence and amount of deformities. Those which are generally given are: Between the anterior-superior iliac spines, 10 inches; between the central points of the crests of the ilia, 10^ inches; between the spinous process of the last lumbar vertebra and the up})er part of the symphysis pubis (external conjugate), 7 inches. Planes of the Pelvis.—By the planes of the pelvis are meant imaginary levels at any portion of its circumference. If we were to cut out a piece of cardboard so as to fit the pelvic cavity, and place it either at the brim Fig. 10. Axes of the Pelvis. A. .\xis of superior plane. b. Axis of niiil ijlatie. c. Axis of inferior plane. D. Axis of canal. e. Horizon. or elsewhere, it would represent the pelvic plane at that particular part, and it is obvious that we may conceive as many planes as we desire. Observation of the angle which the pelvic planes form with the horizon .shows the great obliquity at M'hich the pelvis is placed in regard to the spinal column. Thus the angle a B i (Fig. 9) represents the inclination to the horizon of the plane of the pelvic brim, i B, and is estimated to be about 60°, while the angle which the same plane forms with the ver- tebral column is about 150°. The plane of the outlet forms, with the coccyx in its usual position, an angle with the horizcm of about 11°, but which varies greatly with the movements of the tip of coccyx and the degree to which it is ]-)Ushed l)ack during parturition. These figures nuist onlv be taken as giving an approximate idea of the inclination of the pelvis to the s])inal column, and it nnist be remembered that the degree of inclination varies considerably in the same female at different](https://iiif.wellcomecollection.org/image/b2121072x_0052.jp2/full/800%2C/0/default.jpg)
