On the statics of pregnancy / by Matthews Duncan.

  • Duncan, J. Matthews (James Matthews), 1826-1890.
Date:
1855
Catalogue details

Licence: Public Domain Mark

Credit: On the statics of pregnancy / by Matthews Duncan. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    closely as if it were enveloped in a fluid. No single part can be described as the part supporting it. But with this quali- fication, the nearest approximation to a correct statement of the conditions of its equilibrium is the following ;—It repose.s upon an inclined plane formed by the anterior abdominal wall, and is prevented from moving down the plane by the pelvis. To be at rest upon an inclined plane, a body must have a power exerted upon it to arrest its motion down the plane. In the pregnant female, this is the power exercised by the brim of the pelvis. The power required to resist the pressure down the plane, ^hat is, the pressure on the brim of the pelvis,) is to the vertical pressure on the inclined plane, (that is, the pressure upon the anterior abdominal wall,) as the height of the plane to its length. Now, in an inclined plane, which rises from the horizon at about an angle of 30°, the pressure on the plane itself (that is, on the anterior abdominal wall) must be greater than the pressure in the direction down the plane in the proportion of 87 to 50,^ Thus it is found that the chief support of the uterus is the extensive, equable, soft and elastic abdominal wall, not the comparatively limited, unequable, hard and inelastic pelvic brim. It is not necessai’y to point out at any length the evident application of these views in explaining the production of anterior obliquity of the pregnant uterus, or of pendulous belly. It is upon the anterior abdominal flap that the chief weight of the pregnant uterus reposes, and this part is con- sequently most liable to be morbidly displaced by this pres- sure. “ There is an affection,” . . (says Montgomery,)^ “ con- stantly mistaken for and treated as local inflammation ; I speak of a pain felt at either side about the margin of the ribs, and arising from the dragging of the muscles at their insertions in that situation, especially of the oblique at their superior attachment.” The same circumstances as throw the weight of the uterus on the anterior abdominal muscles, re- move the main pressure of the organs from the brim of the pelvis, through which it would otherwise be more liable to prolapse than it really is. It is here necessary to point out that great misconceptions are entertained in regard to the position of the uterus, in dif- ferent positions of the female. For instance, in attemptiniy to disprove the gravitation-theory of the position of the foetus m utero, to which we shall have afterwai’ds to allude, it has ^ For this calculation, ns for other kindnesses, T am indebted to Mr J. Elliott, Lecturer on ^atural Philosophy. ’ * Signs and Symptoms of Pregnancy, p. 7.