On the graphical representation of the movements of the chest-wall in respiration / by Arthur Ransome.

  • Arthur Ransome
Date:
1875
Catalogue details

Licence: Public Domain Mark

Credit: On the graphical representation of the movements of the chest-wall in respiration / by Arthur Ransome. 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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    which it would produce if its movements were governed simply by the mechanical conditions of the costo-vertebral joints, and by the length and obliquity of the chord-line drawn from its anterior extremity to its head. In consequence of these indications, it seemed desirable that exact graphical tracings of the course described by the ends of the ribs should be obtained, in order that their peculiarities in different cases might be studied. The chief difficulty in the way of obtaining these tracings was found in the fact that the course of the movement lay in three planes, instead of in two only. Observations with the three-plane stethometer, how- ever, had shown that the degree of outward or lateral motion possessed by the ends of the ribs was very small, and that the measurements of this movement were of much less importance than those of the other two, which carried with them interesting practical indications. It seemed better, therefore, to sacrifice the registration of this, the lateral motion, for the sake of bringing the up- ward and forward movements into the same plane. It was easy to do this by resting the whole apparatus, both the pencil and the ground upon which the course was de- scribed, upon a swivel joint, which permitted free rotation with any lateral movement of the chest-wall; and in ex- periments upon the ends of the ribs this motion is so small, that it produces no perceptible effect upon the movements in the upward and forward direction, and any error that it introduces may safely be neglected. The stethograph, then, which I have devised consists of a lever (l), 6 inches long, having a pad (b) at one end, con- nected with it by a ball-and-socket joint, and so shaped as to fit upon the rib, and at the other a finely-pointed pencil (c). This lever is suspended at its central point by a pivot (p), which permits of free movement up and down, but in
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