Lymphology is the medical specialty concerned with lymphatic vessels and their disease. Aside from arteries and veins, the lymphatic vessels make up the third circulatory system of bodily fluids. Lymph collects the serum of the blood that has been pushed into the body tissue, filters it through lymph nodes and returns it to the heart via the venous blood. Destruction of lymphatic vessels often happens as a result of operations, injuries or radiation, the consequences of this are lymphatic congestion and swelling up of the affected body parts. The lymphologist works closely with physiotherapists, who have additional qualifications, as well as medical suppliers. They prescribe suitable compression therapy and bandages as well as physical therapy.