Parasternal Lymph Nodes, Anterior View

Description

Running parallel to the lateral borders of the sternum, the parasternal (internal mammary) lymph nodes form a vertical chain within the anterior thoracic wall, positioned deep to pectoralis major and along the course of the internal thoracic vessels. Superiorly, the chain approaches the level of the first costal cartilage and root of the neck, while inferiorly it continues toward the upper rectus abdominis region adjacent to the costal margin. Costal cartilages and intercostal spaces provide the segmental backdrop, with lymphatic channels converging medially toward the parasternal basin. Symmetry is intentional. Parasternal nodes matter because they sit at a crossroads between superficial lymphatics of the anterior chest wall and deep drainage from the breast, anterior mediastinum, and upper anterior abdominal wall. They are a common pathway for medial-quadrant breast carcinoma spread, and their proximity to the internal thoracic artery places them in the operative field during internal mammary sentinel node biopsy and during vessel harvest for coronary artery bypass grafting. Needle localization and radiotherapy planning also reference this chain. Small nodes, big implications. Use this illustration to teach thoracic wall lymphatic drainage in gross anatomy, breast surgery modules, or oncology lectures that distinguish axillary from internal mammary pathways. It also fits atlases and journal figures discussing internal thoracic vessel anatomy, parasternal nodal irradiation fields, and patterns of metastasis on lymphoscintigraphy or PET-CT correlation. Anatomical accuracy verified by SciePro's Medical Advisory Board.