Axillary Nodes

The axillary lymph nodes are divided into three levels based on their relationship to the pectoralis minor muscle: Level I (low axilla) — lateral to the lateral border of pectoralis minor. Includes the external mammary, subscapular/posterior, and lateral vein/humeral groups. Level II (mid axilla) — behind (deep to) pectoralis minor. Includes the central and interpectoral (Rotter's) nodes. Level III (apical axilla) — medial to the medial border of pectoralis minor, up to the costoclavicular ligament (Halsted's). These are the subclavicular/apical nodes.