The syndrome is approached from the diagnostic and developmental point of view. The clinical examination remains of paramount importance, for it is necessary to differentiate between the primary varices and the post-phlebitic varices which have the same functional symptoms. The main trophic complications are listed, principally: oedema, hypodermititis, ochrodermititis and leg ulceration, which is the most formidable complication and which still occurs very frequently. Ulceration is likely to occur more frequently following sural phlebites rather than those higher up. The main topographical areas of varices are described, without forgetting the collateral circulation in the abdominal and subpudendal region. The developmental aspect of post-phlebitic syndrome is difficult to predict as sequels appear after varying lengths of time, and in varying ways. Finally, venous functional investigations have a practical advantage. They make it possible to assess the functional state of the limb by indicating precisely the state of the deep and superficial circulation. They can thus make it possible to assess the importance of venous stasis and the nutritional state of the tissues.