Corpus: Axillary lymph nodes

The axillary lymph nodes are a group of approximately 20–30 lymph nodes located in the armpit (axilla).

2.1. ...anatomical

The axillary lymph nodes can be broadly classified into:

• Superficial axillary lymph nodes (Nodi lymphatici axillares superficiales)
• Deep axillary lymph nodes (Nodi lymphatici axillares profundi)

A more detailed classification based on their location includes:

• Pectoral (anterior) group (Nodi lymphatici axillares pectorales)
• Interpectoral group (Nodi lymphatici axillares interpectorales)
• Central group (Nodi lymphatici axillares centrales)
• Apical (subclavicular) group (Nodi lymphatici axillares apicales)
• Brachial (lateral) group (Nodi lymphatici axillares brachiales)
• Subscapular (posterior) group (Nodi lymphatici axillares subscapulares)

In a broader sense, the paramammary lymph nodes are also considered part of the axillary lymph nodes.

2.2. ...clinical

Clinically, axillary lymph nodes are divided into three levels based on the hierarchical drainage of lymph from the breast tissue:

• Level I: Lymph nodes in the lower axilla, located lateral to the pectoralis minor muscle.
• Level II: Lymph nodes in the middle axilla, situated between the medial and lateral borders of the pectoralis minor muscle, including the interpectoral lymph nodes between the pectoralis major and minor muscles.
• Level III: Lymph nodes in the upper (apical) axilla, located medial and superior to the medial border of the pectoralis minor muscle, including subclavicular, infraclavicular, and apical lymph nodes.

Axillary lymph nodes are surgically removed during axillary lymph node dissection as part of breast cancer treatment.

A particularly large axillary lymph node, known as Sorgius' lymph node, belongs to the pectoral (anterior) group. It is located on the serratus anterior muscle at the border of the pectoralis minor muscle. In cases of breast cancer metastasis, this lymph node may become hardened and palpable.