AbstractA study has been made of 44 patients with venous insufficiency. Tape recordings of Doppler shift signals during reverse flow in the long saphenous vein have been subjected to frequency analysis to determine whether laminar or turbulent flow was present. Analysis of flow patterns along with evidence of calf muscle pump dysfunction enabled the patients to be classified into three groups:Group 1:Patients showing laminar reverse flow, minimal varices and minimal symptoms.Group 2:Patients with laminar reverse flow, minimal varices, severe symptoms and signs of calf pump dysfunction.Group 3:Patients with turbulent reverse flow, gross varices, negligible symptoms and no evidence of calf pump dysfunction.The relationship between the three groups and their possible prognoses are discussed.