From the Greek word "plethysmo", to increase, and
"graphos" to write
It is the recording of changes in the volume of a limb of digit as blood moves in and out of it with each cardiac cycle.
Pneumatic plethysmogaphy uses a pneumatic cuff wrapped around an extremity or digit. By standardizing the injected volume of air and therefore the pressure inside the cuff, momentary volume changes are detected by a transducer and displayed as waveforms also called "pulse volume recordings."
These waveforms correspond closely with the waveforms obtained by intra-arterial recording at the same level.
Darling, R.C., Raines, J.K. et al. Quantative Segmental Pulse Volume Recorder. A
Surgery 72 - 873 - 887; December 1972.
Winsor, T. - Winsor, D. W. Plethysmography; History and Recent Advances
Angiology; 209 - 218; March 1987.
Birch, G. E. A New Sensitive Portable Plethysmography.
Am Heart J; 23 - 664, 1942