Sample impedance plethysmography recordings from plethysmograph at the critical "shoulder" region of the tracing including the end portion of inflation phase and venous outflow phase,(a)Normal tracing shows good rise in venous capacitance during inflation phase and rapid drop in leg volume during the 3 seconds immediately after deflation of the cuff, indicating absence of venous outflow obstruction,(b)Abnormal tracing in opposite leg of same patient shows diminished venous capacitance and prolonged venous outflow phase.