Tracheobronchial Lymph Nodes

The tracheobronchial lymph nodes are a central group of thoracic lymph nodes situated around the bifurcation of the trachea and the main bronchi. They serve as a critical hub in the lymphatic drainage of the lungs, bronchi, trachea, heart, and mediastinal structures. These nodes are highly relevant in the spread of thoracic malignancies and infections and are routinely evaluated during cancer staging.

Location and Subdivisions

The tracheobronchial lymph nodes are grouped based on their anatomical position relative to the trachea and bronchi. The four main subdivisions include:

• Right tracheobronchial lymph nodes: Located near the right main bronchus and the right side of the trachea
• Left tracheobronchial lymph nodes: Adjacent to the left main bronchus
• Superior tracheobronchial lymph nodes: Located above the tracheal bifurcation
• Inferior tracheobronchial lymph nodes (carinal nodes): Located below the tracheal bifurcation, between the two main bronchi at the carina

Relations

• Superior: Paratracheal lymph nodes
• Inferior: Bronchopulmonary (hilar) lymph nodes
• Anterior: Pulmonary artery and pericardium
• Posterior: Esophagus and thoracic aorta

Afferent Drainage

Lymph reaches the tracheobronchial nodes from multiple thoracic sources:

• Pulmonary (intrapulmonary) lymph nodes
• Bronchopulmonary (hilar) lymph nodes
• Parietal pleura and visceral pleura
• Lower trachea and main bronchi
• Esophagus (thoracic part) and pericardium

Efferent Drainage

The efferent vessels from the tracheobronchial lymph nodes typically ascend to drain into the:

• Paratracheal lymph nodes
• Bronchomediastinal lymph trunks (right and left)
• Eventually into the right lymphatic duct or thoracic duct, depending on the side

Function

• Filter lymph from the lower respiratory tract and thoracic viscera
• Trap pathogens, particulates, and cancer cells before lymph enters systemic circulation
• Serve as major stations for immune surveillance in the thoracic cavity

Clinical Significance (Minimal)

• Metastasis: These nodes are common sites for the spread of lung, esophageal, and bronchial carcinomas
• Lymphadenopathy: Enlarged in conditions like sarcoidosis, tuberculosis, and lymphoma
• Endobronchial ultrasound (EBUS): Allows real-time biopsy of these nodes for diagnosis and staging
• Carinal nodes: Especially important in assessing mediastinal involvement in lung cancer

Radiological Relevance

• Visible on chest CT and PET scans when enlarged
• Carinal and subcarinal nodes are particularly evaluated in lung cancer staging (N2/N3 categories)

Topographic Summary

• Number of groups: Four – right, left, superior, and inferior (carinal)
• Drainage received from: Lungs, bronchi, pleura, heart, trachea
• Drainage output: Paratracheal nodes → bronchomediastinal trunks → right lymphatic or thoracic duct
• Clinical relevance: Central to thoracic oncology, infections, and staging protocols