Lymphatic Drainage

Superficial Drainage - Surface Network

• Origin: Lymphatic plexuses in skin & subcutaneous tissue.
• Course: Generally ascend with superficial veins.
• Main Collecting Pathways:
  • Lateral Vessels (Cephalic Pathway):
    • Accompany cephalic vein.
    • Drain: Thumb, index finger, lateral hand, lateral forearm & arm.
    • Terminate: Mainly deltopectoral (infraclavicular) nodes, some to apical/lateral axillary nodes.
  • Medial Vessels (Basilic Pathway):
    • Accompany basilic vein.
    • Drain: Medial 3 digits, medial hand, medial forearm & arm.
    • Some pass via supratrochlear/cubital nodes to humeral (lateral) axillary nodes.
    • Others drain directly to humeral (lateral) axillary nodes.
• Key Superficial Node:
  • Supratrochlear (Epitrochlear) Node(s):
    • Location: Proximal to medial epicondyle, medial to basilic vein.
    • Afferents: Ulnar side of hand (medial 3 digits), medial forearm.
    • Efferents: To humeral (lateral) axillary nodes or deep lymphatics.

⭐ The supratrochlear lymph node, located superior to the medial epicondyle of the humerus, drains the ulnar aspect of the hand and forearm.

Axillary Node Groups - Central Hub

The axilla contains 5 principal groups of lymph nodes, acting as the primary lymphatic collection hub for the upper limb, pectoral region, and posterior thoracic wall. 📌 Mnemonic: 'ALAP-C' (Anterior, Lateral, Apical, Posterior - Central) for the main groups.

• Anterior (Pectoral) Group:
  • Primarily drains lateral quadrants of the breast and anterior thoracic wall.
• Posterior (Subscapular) Group:
  • Drains posterior thoracic wall, scapular region, and the axillary tail of the breast.
• Lateral (Humeral/Brachial) Group:
  • Receives most lymph from the entire upper limb (except areas with cephalic vein lymphatics).

  ⭐ The lateral (humeral) group of axillary nodes receives the majority of lymph from the upper limb.

• Central Group:
  • Embedded within axillary fat; receives afferents from anterior, posterior, and lateral groups.
• Apical Group:
  • Situated at the axillary apex; receives from central group, infraclavicular nodes, and directly from thumb/upper breast region.
  • Efferents unite to form the subclavian lymphatic trunk, which drains into the venous system.

Applied Anatomy - Flow & Faults

• Final Lymphatic Pathways:
  • Most lymph: Axillary nodes → Supraclavicular nodes → Subclavian lymphatic trunk.
  • Right UL: Subclavian trunk → Right lymphatic duct → Right venous angle.
  • Left UL: Subclavian trunk → Thoracic duct → Left venous angle.
  • Cephalic vein lymphatics may drain directly to infraclavicular/supraclavicular nodes.
• Clinical Significance (Faults):
  • Lymphedema:
    • Post-axillary node dissection/radiotherapy (e.g., breast cancer).
    • Chronic swelling, pain, ↑risk of cellulitis/lymphangitis.
    • Sentinel Lymph Node Biopsy (SLNB) reduces risk.
  • Lymphangitis:
    • Bacterial inflammation of lymphatic vessels (e.g., Strep. pyogenes).
    • Red, tender streaks tracking proximally.
  • Lymphadenopathy:
    • Enlarged axillary nodes; indicates infection, inflammation, or malignancy.
  • Cancer Metastasis:
    • Breast cancer commonly spreads via lymphatics to axillary nodes.
    • Axillary node status is crucial for staging & prognosis.

  ⭐ Lymphedema of the upper limb is a common complication following axillary lymph node dissection or radiotherapy for breast cancer.

High‑Yield Points - ⚡ Biggest Takeaways

• Most upper limb lymph drains to axillary nodes.
• Cephalic vein lymphatics → infraclavicular nodes → apical axillary nodes.
• Basilic vein lymphatics → supratrochlear nodes → lateral axillary nodes.
• Key axillary groups: pectoral (ant.), subscapular (post.), humeral (lat.), central, apical.
• Apical nodes are the final axillary station, draining to the subclavian lymphatic trunk.
• Thumb/radial aspect drains with cephalic vein; little finger/ulnar aspect with basilic vein.
• Lateral breast quadrant primarily drains to anterior (pectoral) axillary nodes.