plethysmograph

A device for measuring and recording changes in volume of a part, organ, or whole body. [G. plethysmos, increase, + grapho, to write]

- body p. a chamber apparatus surrounding the entire body, commonly used in studies of respiratory function.

- digital p. p. applied to a digit of a hand or foot to measure skin blood flow.

- pressure p. 1. a p. applied to part of the body, e.g., a limb segment, and arranged so that volume is measured during temporary application of sufficient pressure to the part to empty its blood vessel s; 2. a body p. in which changes of body volume are measured in terms of the consequent changes in air pressure in the body p..

- volume-displacement p. a p., usually a body p., in which changes in volume displace a corresponding volume into or out of a very compliant measuring device, such as a Krogh spirometer or integrating flowmeter.

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ple·thys·mo·graph -.graf n an instrument for determining and registering variations in the size of an organ or limb resulting from changes in the amount of blood present or passing through it

ple·thys·mo·graph·ic -.thiz-mə-'graf-ik adj

ple·thys·mo·graph·i·cal·ly -i-k(ə-)lē adv

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pleth·ys·mo·graph (plə-thizґmo-graf) [Gr. plēthysmos increase + -graph] an instrument for determining and registering variations in the volume of an organ, part, or limb and in the amount of blood present or passing through it; also used for recording variations in the size of parts and in the blood supply.