Anatomy, Lymph Nodes

The lymphatic system is composed of lymphatic vessels and lymphoid organs such as the thymus, tonsils, lymph nodes, and spleen. These assist in acquired and innate immunity, in filtering and draining the interstitial fluid, and recycling cells at the end of their life cycle. The fluid that leaks from end-stage capillaries returns to the vascular system via the superficial and deep lymphatic vessels, which in turn drain into the right lymphatic duct and the thoracic duct. The right lymphatic duct travels on the medial border of the scalenus anterior muscle and drains the lymph from the right upper quadrant of the body. The thoracic duct starts at the cisterna chyli and has highly variable anatomy. The right lymphatic duct and the thoracic duct drain into the right and left subclavian arteries, respectively, at the jugulovenous angle.Lymph nodes are found at the convergence of major blood vessels, and an adult will have approximately 800 nodes commonly sited in the neck, axilla, thorax, abdomen, and groin. These filter incoming lymph and play a role in infection as well as in malignancy. This paper will discuss the structure and function of lymph nodes, as well as the anatomical divisions of these.