A manual of obstetrics . ac ligament; b,iliofemoral ligament; c, obturator membrane; d, symphysis pubis; e, sacrosciatic liga-ment. and posterior sacroiliac ligajuents, two of each; 2. Thoseconnecting the sacrum and the coccyx, the anterior, pos-terior, and lateral sacrococcygeal ligaments; 3. Those join-ing the two pubic bones, the anterior, posterior, and superiorpubic and the subpubic ligaments ; 4. Those connecting thesacrum and the coccyx with the ilia and the ischia, the twogreater and two lesser sacrosciatic ligaments, the greater ex- GENERATIVE ORGANS AND PARTURIENT CANAL. 29 tending f
A manual of obstetrics . ac ligament; b,iliofemoral ligament; c, obturator membrane; d, symphysis pubis; e, sacrosciatic liga-ment. and posterior sacroiliac ligajuents, two of each; 2. Thoseconnecting the sacrum and the coccyx, the anterior, pos-terior, and lateral sacrococcygeal ligaments; 3. Those join-ing the two pubic bones, the anterior, posterior, and superiorpubic and the subpubic ligaments ; 4. Those connecting thesacrum and the coccyx with the ilia and the ischia, the twogreater and two lesser sacrosciatic ligaments, the greater ex- GENERATIVE ORGANS AND PARTURIENT CANAL. 29 tending from the tubercles of the sacrum to the tuberosityof the ischium, and the ksscr from the lateral margin of thesacrum to the same point. These ligaments are importantas still further modifying the shape of the pelvis and thedirection of its axis, and, in labor, as serving as buffers forthe fetal presentation. The muscles of the pelvis include those of the canal andthose of the pelvic floor, and these have somewhat distinct. Fig. 10.—The levator ani muscle as seen from above, with the tendinous arch that spansthe obturator muscle. obstetric functions. Those of the canal, including the coc-cygeus, pyriformis, and iliopsoas posteriorly and the obtu-rator internus anteriorly, serve to turn the presenting partinto the favorable diameter for its expulsion, and alsoact as cushions upon which the fetus may rest and escapeinjury from undue pressure. Owing to the presence ofthese muscles (the iliopsoas in particular), the transversediameter of the superior strait becomes smaller than theoblique; hence the frequency of oblique fetal positionswhatever the presentation. It has been ascertained thatthese muscles diminish the transverse diameter by abouti^ cm. ( in.), and the congugate by i cm. ( 30 A MANUAL OF OBSTETRICS. in.). The muscles of the pelvic floor are, from withoutinward, the transversus perinei, the ischiocavernosus,the sphincter ani, the sphincter vaginae, the
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectobstetrics, bookyear1
