. Obstetrics for nurses. Fig. 57.—Diagram sliowiiiti ivlation ofplacenta to the uterine wall in thelatter part of pregnancy. (Williams.) THE PHYSIOLOGY OF LABOR 109 from the uterine wall I)y following the line of least resistance. Normally,within a few minutes theafterbirth is completelyseparated and the nextuterine contractionpushes it into the lowersegment and vagina. Theempty uterus is now ableto contract and retractwithout interference, andefficiently controls theloss of blood from thetorn vessels, but there isno satisfactory mechan-ism for the further prog-ress of the placenta, andif left
. Obstetrics for nurses. Fig. 57.—Diagram sliowiiiti ivlation ofplacenta to the uterine wall in thelatter part of pregnancy. (Williams.) THE PHYSIOLOGY OF LABOR 109 from the uterine wall I)y following the line of least resistance. Normally,within a few minutes theafterbirth is completelyseparated and the nextuterine contractionpushes it into the lowersegment and vagina. Theempty uterus is now ableto contract and retractwithout interference, andefficiently controls theloss of blood from thetorn vessels, but there isno satisfactory mechan-ism for the further prog-ress of the placenta, andif left entirely alone itwill usually be so m ehours before it is com-pletely extruded. At thisthe direction of the pelvic. Fig. 58.—Diagram to show separation of placentabv Schultzes mechanism. (Williams.) timeaxis ;ht pressure upon the fundus inufhcient to complete its w o mechanisms ofplacental separation havebeen described and bothare frequently the first, or Schultzesmechanism, the separa-tion occurs near the cen-ter of the organ and thedeveloping hematomapushes the body of theplacenta out through themembranes, so that thefetal surface with the at-tached cord first appearsat the vulva. There isusually no bleeding untilafter the organ is ex-pelled. In the Duncan mechanism, on the other hand, the separationbegins at the margin of the placenta and the spreading hematoma pushes ^^^^^.. %^ W^mSTJm ^S^v^*^_ . ^Si ^^«f^:^9^^ ^^^^^K ^^^^^f^* .^im^ ■ Fig. 59.—Diagram illustrating separation of placentaby Duncans mechanism. (Williams.) 110 TEXTBOOK OF OBSTETRICS FOR NURSES the tissues aside in such a way that the fetal surface is rolled in, and anedge of the maternal surface appear
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectobstetrics, bookyear1
