Inferior Tracheobronchial Lymph Nodes

The inferior tracheobronchial lymph nodes, also known as the carinal lymph nodes, are an essential subgroup of the tracheobronchial lymph node chain. Located at the bifurcation of the trachea, they are a major lymphatic filtering station for lymph from both lungs and the lower trachea. These nodes are critical in thoracic disease evaluation, especially for cancer staging and infection assessment.

Location

• Situated below the tracheal bifurcation (carina), between the origins of the right and left main bronchi

• Positioned in the middle mediastinum, just anterior to the esophagus and posterior to the pulmonary artery

Afferent Drainage

Lymph reaches the inferior tracheobronchial nodes from multiple sources:

• Bronchopulmonary (hilar) lymph nodes of both lungs

• Pulmonary (intrapulmonary) lymph nodes

• Inferior part of the trachea and carinal mucosa

• Main bronchi (especially the proximal regions)

Efferent Drainage

• Superior tracheobronchial lymph nodes located above the carina

• Paratracheal lymph nodes on each side of the trachea

• Bronchomediastinal lymph trunks leading to the thoracic duct (left) or right lymphatic duct

Relations

• Anterior: Pulmonary trunk and left atrium

• Posterior: Esophagus

• Lateral: Right and left main bronchi

• Inferior: Bronchopulmonary (hilar) nodes

Function

• Serve as the first central station for lymph drained from both lungs

• Trap pathogens and tumor cells before lymph ascends toward the venous angle

• Act as a key junction in the thoracic lymphatic drainage hierarchy

Clinical Significance

• Carinal lymphadenopathy: A common finding in lung cancer, especially in central tumors and in staging procedures

• Endobronchial ultrasound (EBUS): Provides direct access for sampling these nodes with high diagnostic yield

• Indicator of metastasis: Enlargement often signifies N2 or N3 staging in non-small cell lung cancer

• Infections: Involved in granulomatous diseases like tuberculosis or sarcoidosis

Radiological Importance

• Chest CT and PET scans: Commonly used to assess size and metabolic activity of carinal nodes

• May appear as a triangular cluster between the main bronchi on imaging

Topographic Summary

• Location: Below the tracheal bifurcation (carina), between main bronchi

• Afferents: From lungs, bronchi, trachea

• Efferents: To superior tracheobronchial and paratracheal nodes

• Function: Filters lymph from both lungs; key station in thoracic lymphatic drainage