Anatomy of the chest wall and axilla

Topographic anatomic depiction of levels I, II, and III of the axillary contents with relation to the neurovascular bundle, pectoralis minor, latissimus dorsi, posterior axillary space, and chest wall. Level I comprises three principal axillary nodal groups: the external mammary group, the subscapular group, and the axillary vein (lateral) group. Level II, the central nodal group, is centrally placed immediately beneath the pectoralis minor muscle. The subclavicular (apical) group is designated level III nodes and is superomedial to the pectoralis minor muscle.