Lymphatic drainage:unidirectional flow of lymph from tissue lymph capillaries, through lymph vessels and lymph nodes, into two principal lymph ducts.
The ducts empty into the great veins at the root of the neck.
Lymph Vessels: Structure and Flow
Lymph vessels have a beaded appearance from numerous valves; valves make lymph flow unidirectional, towards the veins at the root of the neck, preventing backflow.
Lymph passes through a series of lymph nodes before draining into the venous system; the nodes filter the lymph free of pathogens and harmful agents.
By location: superficial lymph vessels, in the superficial fascia deep to the skin, join deep lymph vessels, which lie deep to the deep fascia and accompany blood vessels.