This report presents a study of the methodological aspects of the measurement of venous flow resistance ( Rv) and venous capacity (C10) in human legs as measured by strain-gauge plethysmography. The measurements are reproduceable within 10%, in subjects who are well-acclimatized to a room temperature of 28–30 °C. In measurements at the calf, extension of the knee joint may increase Rv by hundreds of percents, while high passive calf muscle tension may be associated with a decrease in Rv and an increase in C10. Inadequate acclimatization may increase Rv and decrease C10, notably in measurements at the foot. The determinants for Rv and C10 are discussed.

This report presents normal values of venous flow resistance ( Rv) and venous capacity (C10) as measured in human limbs by strain-gauge plethysmography. No age dependency was found for either parameter. Rv was lower in males than in females and lower in left legs than in right legs. C10 was higher in males than in females and higher in left than in right legs. The left-right and sex dependency of the parameters cannot be explained by differences in limb volume. Correlations between selected parameters are presented.

Venous flow resistance ( Rv) and venous capacity ( C10)2 was studied in humans with deep vein thrombosis (DVT) using strain-gauge plethysmography. Rv was found to be significantly higher than normal while C10 was significantly lower, notably in measurements at the calf-level. In a follow-up study it was demonstrated that Rv usually decreased sharply within the first few months after the acute event while C10 increased. Rv usually returned to (high-level) non-thrombotic values, while C10 returned to (low-level) normal values. The sensitivity of Rv when used as a diagnostic criterion for recent proximal DVT was assessed retrospectively. For proximal DVT, the sensitivity of Rv-prox (measured with strain-gauges around the calf) was 95% (95% confidence limits 83–99%) and for distal DVT, the sensitivity of Rv-dist (measured with strain-gauges around the foot) was 36% (95% confidence limits 13–65%). The specificity for Rv was 100% (95% confidence limits Rv-prox: 90–100%; Rv-dist: 59–100%). Influencing factors for sensitivity and specifity are discussed.

Venous flow resistance ( Rv) and venous capacity ( C10) was measured by strain-gauge plethysmography in patients with primary truncal varicosis of the long saphenous vein (LSV). Rv tended to be lower than normal, notably in measurements taken at the foot, but significant differences were hardly demonstrable. C10 in the calf and the foot were significantly higher than normal. Physical and morphological abnormalties of the LSV with relevance to Rv and C10 are discussed. It was demonstrated that the contribution of the LSV to venous haemodynamics amounts to about 10%. It is considered unlikely that the sensitivity of Rv, when used as a diagnostic criterion for recent deep vein thrombosis, is influenced by the LSV.

Venous flow resistance ( Rv) and venous capacity ( C10) was measured by strain-gauge plethysmography in patients with primary lympoedema of the legs. In the calf, Rv was significantly higher than normal and increased with the clinical severity of the oedema, while C10 was significantly lower than normal. Potential causes are discussed. No indications were found that the specificity of Rv, when used as a diagnostic criterion for recent deep vein thrombosis, is influenced by primary lymphoedema.