The venous and liver pulses, and the arhythmic contraction of the cardiac cavities / by James Mackenzie.

  • James Mackenzie
Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: The venous and liver pulses, and the arhythmic contraction of the cardiac cavities / by James Mackenzie. Source: Wellcome Collection.

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

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    the method employed could not be trusted to record movements in the vein alone, but also frequently showed curves that were un- doubtedly due to the carotid pulse, it is necessary to consider shortly the relation of the vein to the artery, and to demonstrate how the artery makes itself appear in the tracing. This is all the more neces- sary, as the failure to recognise this arterial influence has misled various observers. The intimate association of the arteries with their accom- panying veins, has been long recognised; and Hunter,^ Eicherand,^ and King 3 considered that arterial pulsation was one of the factors that caused the blood in the veins to move, this effect being favoured, as Ozanam ^ demonstrated, by the inclusion of arteries and veins in a common sheath. The sudden movement communicated to the surrounding tissues by the carotid pulse may be considered to act in two ways. While the artery expands in all directions, it of course pushes against the structures in its immediate neighbourhood. In doing so, it will elevate the tissues that lie superflcial to it, and these being displaced v/ill drag upon those more distant from the artery. It will thus happen that there are practically two influences of the carotid impulse—one of elevation and the other of depression. If the receiver be placed over the artery, a tracing of the arterial pulse will be obtained; if the receiver be placed a little distance away, then a depression occurs coincident with the arterial pulse (Fig. 9). The lower tracing in Fig. 9 was taken half an inch behind the carotid in the middle of the neck, and shows a tracing the reverse of the upper taken from over the car- otid—a negative carotid sphygmogram in fact. The patient from whom the tracing was taken (Case 32) had a small enlargement of the right thyroid gland, which pushed the carotid back, so that it lay alongside the posterior border of the sterno-mastoid muscle, and the neck was a very spare one. I mention this negative pulse wave, as a similar negative wave in the veins has been ascribed to this cause by Ozanam, and it will remove a possible source of misunder- standing, when the events in the venous pulsations are considere . Arterial xoave.—^^ the methods I have employed to obtam traemga Fig. 9.—The upper ti'acing was taken with the receiver over the carotid artery, at the same time as the lower one was taken with the receiver about half an inch away from the carotid artery. The lower tracing is the inverse of the upper. ^ Hunter, J., ^ Richerand, '. ext. p. 227. . 1 1 ooo “Elements of Physiology,” edited by J. Copland, 2nd edition, 1829, p. 186. ^ King, W., loc. cit. p. 104. . ■ j.- ” •* “Nouveau Dictionnaire de MMicine et de Chirurgie Iratiques, tome xxxviii. p. 649.
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