Parasternal Lymph Nodes

Description

Running just lateral to the sternum, the parasternal (internal mammary) lymph nodes are rendered as a green nodal chain accompanying the internal thoracic artery and veins within the anterior thoracic wall. Superiorly, the chain approaches the root of the neck near the clavicle, where lymphatic channels converge toward the venous angle, while inferiorly it continues along the internal thoracic vessels toward the intercostal spaces. Portions of the manubrium and adjacent costal cartilages provide a medial bony reference, and the superficial and infrahyoid musculature of the lower neck frames the superior extent of the field. Orientation is clear. Medial is sternal. Clinically, this nodal basin matters because it is a primary drainage pathway for the medial breast and anterior thoracic wall, and its involvement can alter staging and radiation fields in breast carcinoma even when axillary nodes appear negative. The close relationship to the internal thoracic artery also explains why parasternal node sampling or internal mammary sentinel node biopsy demands careful hemostasis and a deliberate parasternal approach through intercostal spaces. In reconstructive surgery, the same anatomy intersects with exposure of internal mammary vessels for free-flap anastomosis, where lymphatic tissue can obscure the vascular pedicle. Educators can drop this figure into modules on lymphatic drainage of the thorax, breast oncology pathways, and the surgical anatomy of the internal thoracic vessels, where students often confuse parasternal nodes with supraclavicular chains. It also suits radiology and oncology teaching files that correlate internal mammary node enlargement on CT, MRI, or PET-CT with the expected course of the internal thoracic vessels. Anatomical accuracy verified by SciePro's Medical Advisory Board.