Intercostal Lymph Nodes

The intercostal lymph nodes are a group of small lymphatic structures located in the posterior thoracic wall. They are associated with the intercostal spaces and lie near the heads and necks of the ribs, adjacent to the intercostal vessels. These nodes are responsible for draining lymph from the posterolateral thoracic wall, deep back muscles, vertebrae, and overlying skin.

Location

• Found in the posterior intercostal spaces, particularly from the 3rd to 11th intercostal spaces
• Lie near the vertebral column, close to the heads of ribs
• Closely associated with the posterior intercostal arteries and veins

Afferent Drainage

The intercostal lymph nodes receive lymph from:

• Posterolateral thoracic wall, including skin, intercostal muscles, and ribs
• Deep back muscles and fascia
• Parietal pleura in the posterior thoracic cavity

Efferent Drainage

• Upper intercostal nodes (1st–2nd spaces) drain into brachiocephalic or paratracheal lymph nodes
• Middle and lower intercostal nodes drain into the thoracic duct (on the left)
• On the right side, they may drain into the right lymphatic duct or bronchomediastinal trunk

Function

• Filters lymph from the deep thoracic wall and posterior pleura
• Serves as an intermediate checkpoint for lymph en route to the central thoracic ducts
• Participates in immune defense against pathogens in the posterior thorax

Relations

• Anterior: Intercostal muscles and thoracic cavity
• Posterior: Vertebral bodies and spinal nerves
• Superior: Posterior intercostal arteries and veins
• Medial: Thoracic sympathetic chain

Clinical Significance

• Lymphadenopathy: These nodes can enlarge due to infections (e.g., tuberculosis), malignancies, or systemic disease
• Metastatic spread: Involved in posterior thoracic wall cancers and some forms of lung or pleural malignancy
• Surgical relevance: Rarely biopsied directly but may be involved in thoracotomy or rib resection procedures

Topographic Summary

• Location: Along posterior intercostal spaces, near ribs and vertebrae
• Afferents: From thoracic wall, back muscles, pleura
• Efferents: To thoracic duct, right lymphatic duct, or paratracheal nodes
• Function: Drains posterolateral thoracic structures; key in thoracic wall immunity