Volume 1

A treatise on the science and practice of midwifery / by W.S. Playfair.

Date:
1886
Catalogue details

Licence: Public Domain Mark

Credit: A treatise on the science and practice of midwifery / by W.S. Playfair. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

    35/442 (page 9)
    Chap. I.] • ANATOMY OF THE PELVIS. direction take place in them, wliich materially enlarge the pelvic canal during labour. It is extremely probable that similar movements take Mode in place in women, both in the symphysis pubis and in the J^^-* ^ sacro-iliac ioints, although to a less marked extent. These ments are are particularly well described by Dr. Duncan. They seem to consist chiefly in an elevation and depression of the sym- physis pubis, either by the ilia moving on the sacrum, or by the sacrmn itself undergoing a forward movement on an imaginary transverse axis passing through it, thus lessening the pelvic brim to the extent of one or even two lines, and increasing, at the same time, the diameter of the outlet, by tilting up the apex of the sacrum. These movements are only an exaggeration of those which Zaglas describes as occur- ring normally during defgecation. The instinctive positions which the parturient woman assumes find an explanation in these observations. During the first stage of labour, when the head is passing through the brim, she sits, or stands, or walks about, and in these erect positions the symphysis pubis is depressed, and the brim of the pelvis enlarged to its utmost. As the head advances through the cavity of the pelvis, she can no longer maintain her erect position, and she lies down and bends her body forward, which has the effect of causing a nutatory motion of the sacrum, with corresponding tilting up of its apex, and an enlargement of the outlet. These movements during parturition are facilitated by Altera- the changes which are known to take place in the pelvic thTpeWic articulations during pregnancy. The ligaments and carti- joints lages become swollen and softened, and the synovial mem- p^eg^^ branes existing between the articulating surfaces become nancy, greatly augmented in size and distended with fluid. These changes act by forcing the bones apart, as the swelling of a sponge placed between them might do after it had imbibed moisture. The reality of these alterations receives a clinical They illustration from those cases, which are far from uncommon, continue m which these changes are carried to so extreme an extent after de- that the power of progression is materially interfered with ^'^^^'y- for a considerable time after delivery. On looking at the pelvis as a whole, we are at once struck Pelvis as a with its division into the true and false pelvis. The latter