Inasmuch as the pessary fulfils its indications by sustaining the pelvic floor, and thereby holding the cervix in the hollow of the sacrum, the same general principles, and in fact the same pessaries, which are applicable to prolapse apply also to retroversion and retroflexion. Indeed, the first step in the genesis of the retro-positions has been shown to be prolapse. The student is therefore referred to the general remarks on the adjustment of pessaries for prolapse. The operations of elytrorraphy and perineorraphy, especially the latter, already described in the treatment of descent, are often of the utmost importance in the treatment of the posterior displacements, and should therefore be carefully studied in this connection. In the adjustment of the pessary it is desirable, if possible, to avoid direct pressure upon any part of the uterus. Pessaries designed to prop up the body of the uterus by pressure upon the posterior wall to correct the posterior malpositions, and upon the anterior wall to correct the anterior malpositions, are very liable to induce metritis and perimetritis, and are therefore generally unsafe. In certain cases, however, the vaginal walls, {172} especially the posterior, may be so relaxed from subinvolution and other causes that the instrument, though very long, fails to maintain the cervix in its normal place. Under such conditions a pessary may be required to act directly upon the uterus. The Schultze's sleigh pessary represented in Fig. 19 fulfils this indication. Schultze's figure-of-eight pessary, or a long Albert Smith pessary with its uterine curve made so extreme as to bring the upper part of the instrument in front of the cervix instead of behind, answers the same purpose. [Illustration: FIG. 18. Showing the Pelvic Organs sustained by the Emmet Pessary alter reposition of the prolapsed, retroverted or retroflexed uterus.] Thomas's retroflexion pessary, with its bulbous upper extremity, is a long narrow instrument of extreme uterine curve. It lifts the uterus very high, and is specially applicable in cases of great relaxation of the pelvic floor and of complicating prolapse of the ovaries (Fig. 21). The bulbous portion is sometimes made of soft rubber. A properly-adjusted pessary gives to the patient no consciousness of its presence. If the instrument cause pain it should be removed and search made for the tender places; it should then, if possible, be remoulded into such shape that it will not exert pressure upon them. Often a slight indentation at some point will enable the patient to wear it with comfort.