Physical diagnosis : a guide to methods of clinical investigation / by G.A. Gibson and William Russell.

  • George Alexander Gibson
Date:
1890
Catalogue details

Licence: Public Domain Mark

Credit: Physical diagnosis : a guide to methods of clinical investigation / by G.A. Gibson and William Russell. Source: Wellcome Collection.

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    noted in relation to the number of beats as 1 in 10-12, or whatever the number may be. Modifications of the Second Sound. A. Diminution in the intensity of the second sound occurs in all conditions where the power of the ventricles is diminished. The blood, under such circumstances, is pro- pelled into the aortic and pulmonary arteries with less vigour, and also in diminished volume, and as a consequence the elastic recoil of these vessels is lessened. It is reasonable to assume that if the ventricles be materially weakened, the volume of blood propelled by each systole must be reduced— that, in fact, the ventricles do not empty themselves to the extent they do normally. That this must be the case is borne out by the results observed in fatty heart where the pulmonary circulation and the systemic venous circulation become engorged. That the intensity of the second sound depends on the elastic recoil of the vessels is abundantly proved by physiological and pathological observations. B. Accentuation of the second sound may have its seat at either of the arterial orifices. The method by which it is determined at which orifice the accentuation occurs is as follows :—The second sound, it will be remembered, is nor- mally louder in the aortic area than in the pulmonary; when, therefore, it is as loud, or louder, in the pulmonary area than in the aortic, it indicates accentuation of the pulmonary second sound. Accentuation of the aortic second sound can only be estimated by a knowledge of its average loudness under normal conditions. Accentuation of the pulmonary second sound results from any obstruction to the pulmonary circulation, whether due to valvular lesion at the mitral orifice, or to lesions of the lungs themselves, such as emphysema, &c, which obstruct the capillary circulation. Accentuation of the aortic second sound depends on obstruction in the arterial circulation, and is a concomitant of
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