It consists of two separate entities, the deep venous system and the superficial venous system.

The deep venous system represents 90% of total venous return and follows the path of the arteries. The most commonly encountered venous pathology in this network is phlebitis and its consequences are the postphlebitic disease, the most formidable, pulmonary embolism.

The superficial venous system accounts for 10% of the venous drainage of the lower limbs. Its main saphenous veins or great saphenous vein and the saphenous or small saphenous vein. There are also accessories or collateral veins throwing in these two main veins.

This is at the expense of the superficial venous network that develop varicose veins.