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A textbook of obstetrics . nsiderably symphysis has less of a slant outward than it should have ;tin: promontory is found low and prominent ; the sacral bone issharply bent upon itself, and the pelvic canal is remarkablyshallow. On account of the increase in the conjugatosymphys-eal angle due to the lessened slant outward of the symphysis,at least two centimeters should be subtracted from the diagonalconjugate. The difference between the two would be greaterwere it not for the- low situation of the promontory, which com-pensates to a certain extent for the lessened slant of the svm
A textbook of obstetrics . nsiderably symphysis has less of a slant outward than it should have ;tin: promontory is found low and prominent ; the sacral bone issharply bent upon itself, and the pelvic canal is remarkablyshallow. On account of the increase in the conjugatosymphys-eal angle due to the lessened slant outward of the symphysis,at least two centimeters should be subtracted from the diagonalconjugate. The difference between the two would be greaterwere it not for the- low situation of the promontory, which com-pensates to a certain extent for the lessened slant of the svm- ANOMALIES IX THE FORCES OF LABOR. 447 pin-sis, hut does not entirely neutralize it. If a double promon-toryis found, which in these pelves is not uncommon (Fig. 306),the measurement should be taken from the promontory nearestthe symphysis. (Occasionally the lordosis of the lumbar vertebrae,the result of spinal rachitis, is so great as to constitute itself anobstruction above the pelvic inlet. In such a case the effective. Fig- 3°3-—Rachitic dwarf; height, 4 feet, I inch. Conj. vera, 6 cm. Cesareansection (Howard Hospital). conjugate must be taken from a point above the sacrum to thesymphysis pubis. Influence on Labor.—The influence of a flat rachitic pelvis onlabor is much the same as the influence of a simple tlat pelvis,except that the contraction, and consequently the obstruction tolabor, is greater in the rachitic form, and that the promontory ofthe sacrum is more prominent and more sharply defined. Theanomalies of mechanism at the inlet are the same in both varie-ties of pelvis, but they are exaggerated in the flat rachitic soon as the obstruction at the inlet is overcome, the descent 448 THE PATHOLOGY OF LABOR.
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Keywords: ., bookcentury1800, bookdecade1890, bookidtex, booksubjectobstetrics