Full Immune and Lymphatic Systems of the Upper Torso Description
[Continued from above] . . . lymph nodes trap pathogens so that antibodies can attack them; the byproducts of this attack (dead bacteria or viral particles and dead or damaged antibodies and white blood cells) can then be flushed out of the body along with the lymph fluid. This prevents excessive buildup in the body of the poisonous products of cellular decay.
Lymph fluid from the head and neck also drains into this region via the jugular trunks (in the neck) to settle into the right and left lymphatic ducts, which are near the clavicle on the right and left side of the body, respectively. Any lymph which is not released back into the body from these ducts drains into the subclavian trunks and from there into the bronchomediastinal trunks. The subclavian trunks also drain lymph from the upper extremities - that is, the arm - while the bronchomediastinal trunks drain fluid from the entire upper body, including large portions of the thorax. The thoracic duct is a collection duct, where lymph pools and is processed for release into the body; after leaving the thoracic duct, lymph enters the veins to become part of the plasma just before the blood returns to the right atrium of the heart.