The attitude and positions, natural and preternatural, of the fœtus in utero, acts of the reflex or excito-motory system / by J. Y. Simpson.

  • James Young Simpson
Date:
1849
Catalogue details

Licence: Public Domain Mark

Credit: The attitude and positions, natural and preternatural, of the fœtus in utero, acts of the reflex or excito-motory system / by J. Y. Simpson. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    so that the two ovoids which the fcetus and uterus form are rela- tively adapted to each other; that is, the broad or pelvic end of the ovoid of the foetus, is placed towards the broad or upper end of the ovoid of the uterus; while the narrow or cephalic end of the ovoid of the foetus, is placed towards the narrow or lower end of the ovoid of the uterus. The narrow and broad ends of the ovoid mass of the foetus, are relatively adapted to the narrow and broad ends of the ovoid cavity of the uterus. The figure of the contained body (the foetus) thus comes to correspond with the figure of the containing body (the cavity of the uterus), and is, as it were, fitted into it. Fig. 3 in Plate II. represents the one ovoid (Fig. 1) thus adapted to the other ovoid (Fig. 2). At the advanced time of pregnancy of which we are speaking, when the uterus and foetus are normal in shape and size, the foetus cannot be placed transversely in the uterine cavity, so as to form a transverse or arm presentation, as there is not room for it to lie in that position. For the long axis of the ovoid mass of the foetus is about twelve inches; the greatest breadth of the uterus is only eight inches; so that the latter could not receive the former. For the same reason, when once the position with the head downwards is assumed, it comes to be difficult or impossible for the child near the full time to move round in utero, so as to turn its pelvic, instead of its cephalic extremity downwards, and towards the os. In fact a compressible body of twelve inches in length, such as the rolled up foetus is, cannot readily move through a space of only eight or nine inches, even though that space, like the transverse axis of the uterine cavity, be capable of dilatation and forcible alteration of shape. At, and towards the full terra of utero-gestation, the position of the foetus with the head lowest, is thus greatly maintained by the relative physical adaptation of the ovoid shape of the rolled up mass of the foetus, to the ovoid shape of the interior of the cavity of the uterus. But this particular adaptation and position of the foetus in the uterine cavity, wovJd be often lost if no other additional and vital means were in operation; as we see indeed often happen when the child dies. The other additional vital means, by whose influence this special position is still further, rigorously and carefully sustained, consists of the restor- ing influence of reflex motions on the part of the foetus itself. For, let the relative adaptation and position of the foetus be partially dis- turbed (as readily happens by any movements of the mother, as, for example, by her suddenly assuming the upright or supine pos- tures, or other such causes), and immediately the foetus, by a series of reflex movements of its extremities, particularly of its lower ex- tremities, acts till it regains its former perfect position. It moves, in other words, till it has retaken that position in which it is most free from any marked excitations or com])ressions upon the external sur- face of its own body. It is perhaps unnecessary to add, that seeing the foetus is placed in