Breast Lymphatic Drainage
Shared 12/22/2025•47 views
Breast Lymphatic Drainage The lymphatic system plays a crucial role in draining fluid, immune cells, and waste products from the breast tissue. Understanding its pathways is vital in clinical contexts, especially regarding breast cancer metastasis. Key Lymph Node Groups Axillary Lymph Nodes: Approximately 75% of breast lymph drains to the axilla. These are further subdivided: Pectoral (Anterior) Nodes: Lie along the lateral border of pectoralis minor, draining the lateral and inferior parts of the breast. Subscapular (Posterior) Nodes: Along the subscapular artery, draining the posterior wall of the axilla and some breast tissue. Humeral (Lateral) Nodes: Along the axillary vein, draining most of the upper limb. Central Nodes: Embedded in the fat of the axilla, receiving lymph from pectoral, subscapular, and humeral nodes. Apical (Subclavian) Nodes: At the apex of the axilla, receiving lymph from all other axillary nodes. They drain into the subclavian lymphatic trunk. Parasternal (Internal Mammary) Lymph Nodes: Located along the internal thoracic artery, draining the medial part of the breast. These nodes drain into the bronchomediastinal trunk. Supraclavicular Lymph Nodes: Lymph can drain here from the apical axillary nodes. Infraclavicular (Deltopectoral) Lymph Nodes: Receive lymph from the upper outer quadrant of the breast. Contralateral Breast/Abdominal Lymph Nodes: In some cases, lymph can cross the midline to the opposite breast or drain to nodes in the abdomen (e.g., via rectus sheath). Drainage Pathways Lymphatic capillaries originate in the breast tissue. They coalesce into larger lymphatic vessels. Most vessels (approx. 75%) follow blood vessels to the axillary lymph nodes. A significant portion (approx. 25%) from the medial breast drains to the parasternal (internal mammary) lymph nodes. Minor drainage pathways include infraclavicular and supraclavicular nodes. From the axillary nodes, lymph ascends through central and apical nodes. Ultimately, lymph enters the venous system via the subclavian lymphatic trunk (on the left, into the thoracic duct; on the right, into the right lymphatic duct). Clinical Significance Sentinel Lymph Node Biopsy: Identification of the first lymph node(s) to receive drainage from a tumor, crucial for staging breast cancer. Metastasis: Lymphatic spread is a primary route for breast cancer cells to metastasize to distant sites. The pattern of nodal involvement helps predict prognosis. Lymphedema: Damage or removal of lymph nodes (e.g., during surgery or radiation) can impair lymphatic drainage, leading to swelling in the arm or breast. Diagram of Breast Lymphatic Drainage Axillary Nodes Parasternal Nodes Supraclavicular Breast Lymphatic Drainage Upper Outer Upper Inner Lower Outer Lower Inner