A treatise on the science and practice of midwifery . ANATOMY OF THE PELVIS. 47 each other than they afterward become; the pelvic viscera are conse-quently crowded up into the abdominal cavity, which is, for this reason,much more prominent in children than in adults. The bones are softand semi-cartilaginous until after the period of puberty, and vieldreadily to the mechanical influences to which they are subjected; andthe three divisions of the innominate bone remain separate until aboutthe twentieth year. As the child grows older the transverse development of the sacrumincreases, and the pelv
A treatise on the science and practice of midwifery . ANATOMY OF THE PELVIS. 47 each other than they afterward become; the pelvic viscera are conse-quently crowded up into the abdominal cavity, which is, for this reason,much more prominent in children than in adults. The bones are softand semi-cartilaginous until after the period of puberty, and vieldreadily to the mechanical influences to which they are subjected; andthe three divisions of the innominate bone remain separate until aboutthe twentieth year. As the child grows older the transverse development of the sacrumincreases, and the pelvis begins to assume more and more of the adultshape. The mere growth of the bones, however, is not sufficient toaccount for the change in the shape of the pelvis, and it has been well Fig. Pelvis of a Child. shown by Duncan that this is chiefly produced by the pressure to which thebones are subjected during early life. The iliac bones are acted upon bytwo principal and opposing forces. One is the weight of the body above,which acts vertically upon the sacral extremity of the iliac beam throughthe strong posterior sacro-iliac ligaments, and tends to throw the loweror acetabular ends of the sacro-cotyloid beams outward. This outwarddisplacement, howTever, is resisted, partly by the junction between thetwo acetabular ends at the front of the pelvis, but chiefly by the oppos-ing force, which is the upward pressure of the lower extremities throughthe femurs. The result of these counteracting forces is that the still softbones bend near their junction with the sacrum, and thus the greatertransverse development of the pelvic brim characteristic of adult life isestablished. In treating of pelvic deformities it will be seen that thesame forces applied to diseased and softened bo
Size: 1853px × 1349px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1880, booksubjectobstetrics, bookyear1
