A 40-year-old woman has a carcinoma of the upper outer quadrant of the right breast. The primary lymphatic drainage of this region is to which node group?
- A Internal mammary (parasternal) nodes
- B Posterior (subscapular) axillary nodes
- C Anterior (pectoral) axillary nodes ✓
- D Supraclavicular nodes directly
Correct answer: C. Anterior (pectoral) axillary nodes
Explanation
About 75% of breast lymph drains laterally to axillary nodes; the upper outer quadrant drains predominantly to the anterior (pectoral) group of axillary nodes (Level I), which lie along the lateral thoracic vessel medial to the pectoralis minor. From there, lymph flows to central (Level I-II) then apical (Level III) nodes. The internal mammary nodes receive primarily medial quadrant drainage. Posterior (subscapular) nodes receive drainage from the back and posterior shoulder. Direct supraclavicular drainage is a Rotter's pathway and an advanced/alternative route.
Reference: BD Chaurasia's Human Anatomy, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.