Obstetrics for nurses / by Joseph B. De Lee.

  • Joseph DeLee
Date:
1913
Catalogue details

Licence: In copyright

Credit: Obstetrics for nurses / by Joseph B. De Lee. Source: Wellcome Collection.

    29/538 page 24
    The true or small pelvis is just below the large pelvis; behind, it is made up of the sacrum and the coccyx; at the sides, by the innominate bones; and in front, by the rami of the innominate bones. In front it is only 2 inches high, but behind it is 6 inches. The bony pelvis is exceedingly irregular in outline, having many notches, and several openings through which various structures— muscles, nerves, blood-vessels, etc.—pass. In general, the shape of the cavity of the true pelvis is that of an elbow of stovepipe. Where the true and false pelves join there is a more or less marked rim. This place is called the inlet, brim, or upper strait, the pelvis being narrower here (Figs. 2, 5). At the lower end of the true pelvis is the outlet (Figs. 3,6). The inlet is shaped like a flattened heart; the outlet, an antero- posterior ellipse, so that an ovoid body like the baby’s head, passing through the inlet in the transverse diam- eter, in order to escape from the outlet must turn its long diameter to correspond with the long diameter of the outlet (Figs. 7, 8). This occurs during labor and is called “rotation.” Since the cavity of the pelvis is curved—a bent canal the head must slide along it, taking a curved course;
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