Parasternal Lymph Nodes Without the Muscles, Anterior View

Description

Running parallel to the lateral borders of the sternum, the parasternal (internal mammary) lymph nodes form a vertical chain in the anterior thoracic wall, closely applied to the costal cartilages and the adjacent intercostal spaces. Superiorly, the clavicles bracket the manubrium, while the ribs sweep laterally from the sternum to define the thoracic cage; with the pectoral musculature removed, these osseous and cartilaginous landmarks read cleanly in anterior orientation. Fine lymphatic collecting vessels converge on the parasternal nodes, and segmental intercostal nerves course laterally within each intercostal space, visually separating neural pathways from lymphatic drainage. Parasternal nodes matter because they sit on a key drainage route from the medial breast, anterior chest wall, and upper epigastrium, a pathway that can bypass axillary nodes and alter staging in breast carcinoma. Their relationship to the internal thoracic (mammary) vessels and costal cartilages underpins both sentinel lymph node mapping of the internal mammary chain and targeted radiotherapy planning along the parasternal region. Small structures, high consequence. Use this artwork in gross anatomy and lymphatic system teaching to clarify anterior thoracic wall drainage patterns, or in surgical and oncology publications discussing internal mammary sentinel nodes, parasternal irradiation fields, and patterns of metastatic spread. It also supports clinical education on why medial breast tumors may present with internal mammary node involvement despite a clinically negative axilla. Anatomical accuracy verified by SciePro's Medical Advisory Board.