Interpectoral Lymphatics Associated With the Mammary Gland, Gross Anatomy

Description

Anterior chest wall anatomy is rendered with the mammary gland in situ overlying pectoralis major, with the glandular lobules and lactiferous ducts embedded within subcutaneous adipose tissue and oriented toward the nipple areola complex. Deep to the breast parenchyma, lymphatic collecting vessels course posteriorly toward the interpectoral (Rotter) lymph nodes situated between pectoralis major and pectoralis minor, then continue medially and superiorly toward the apical axillary chain. Superficial veins and accompanying arterial branches are shown in relation to the gland and the muscle fascia. Small but telling. Interpectoral lymphatics matter because they sit on a common pathway of metastatic spread from the posterior and central breast to the axilla, sometimes bypassing the more superficial pectoral (anterior) axillary nodes. Surgeons encounter this space during axillary dissection and when developing the plane for mastectomy or implant based reconstruction, and awareness of Rotter nodes can explain a positive sentinel node in an unexpected location. Radiologists and breast imagers also reference this deep drainage route when correlating posterior tumor location with nodal staging and recurrence patterns. Use this plate for teaching lymphatic drainage of the breast in gross anatomy, surgical anatomy, and oncology modules, or as a figure in manuscripts discussing sentinel lymph node biopsy, axillary staging, and patterns of spread in breast carcinoma. It also supports patient facing education materials that need an accurate depiction of deep versus superficial lymphatic pathways without oversimplifying the interpectoral compartment. Anatomical accuracy verified by SciePro's Medical Advisory Board.