A text-book of physiology, for medical students and physicians . rift, 1903, 1904. 492 CIRCULATION OF BLOOD AND LYMPH. pressures, and the same is true, of course, of arterial and capillarypressures, there must be some agreement as to what constitutesthe heart-level, since the highest and lowest points of the heartwhen the individual is standing or sitting may differ by as muchas 15 centimeters, von Recklinghausen proposes the levelmade by a dorsoventral line drawn from the bottom of thesternum (costal angle) to the spinal column. This authorf hasdevised a simple apparatus for determining venou
A text-book of physiology, for medical students and physicians . rift, 1903, 1904. 492 CIRCULATION OF BLOOD AND LYMPH. pressures, and the same is true, of course, of arterial and capillarypressures, there must be some agreement as to what constitutesthe heart-level, since the highest and lowest points of the heartwhen the individual is standing or sitting may differ by as muchas 15 centimeters, von Recklinghausen proposes the levelmade by a dorsoventral line drawn from the bottom of thesternum (costal angle) to the spinal column. This authorf hasdevised a simple apparatus for determining venous and capillarypressures, the principle of which is shown by the schema repre-sented in Fig. 203. A circular bag of thin rubber with a diameter of about 5J cm. is providedwith a central opening of 2 cm. The bag is connected with a pump so thatit can be blown up, and the degree of pressure exerted is measured by anattached manometer. This bag, moistened with glycerine, is laid upon avein, as represented in the diagram. It is covered by a glass plate held firmly. Fig. 203.—To illustrate the method of measuring venous pressure: //, The back ofthe hand in which a single vein is represented; B, the circular rubber bag with centralopening, and with a tube, T, which leads to the pump and the manometer; G, glass plateheld over the rubber bag. The bag, B, is blown up by pressure through the tube T untilthe vein is collapsed. The pressure at which this occurs, or the pressure at which thevein reappears as the bag is allowed to empty, gives the pressure within the vein.—(vonRecklinghausen.) in posil ion and the bag is then blown up until the vein disappears; the pressureat which this happens is shown by the manometer and marks (lie pressurewithin iho vein. A convenient modification of this apparatus which liasbeen described by Eyster and Hookerf is shown in Fig. 20 1. The box, />,used for compressing the vein is connected by rubber tubing will: a rubbermanometer, Cf, and a pressure
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