Diaphragmatic Lymph Nodes

The diaphragmatic lymph nodes are a group of thoracic lymph nodes situated on the superior and inferior surfaces of the diaphragm. They form part of the lymphatic network involved in draining the diaphragm itself, as well as adjacent thoracic and upper abdominal structures. Though small and often few in number, they serve as key conduits for lymph passing between the thoracic and abdominal cavities.

Location

• Superior diaphragmatic lymph nodes: Located on the thoracic (superior) surface of the diaphragm
• Inferior diaphragmatic lymph nodes: Located on the abdominal (inferior) surface of the diaphragm, near its attachments

Afferent Drainage

Diaphragmatic lymph nodes receive lymph from a variety of regions:

• Central portion of the diaphragm (muscular and tendinous areas)
• Pericardium (especially the fibrous pericardium)
• Anterior abdominal wall (upper midline region)
• Liver (especially segments adjacent to the diaphragm via the falciform ligament)
• Diaphragmatic pleura and peritoneum

Efferent Drainage

• Anterior diaphragmatic nodes: Drain into parasternal lymph nodes
• Posterior diaphragmatic nodes: Drain into posterior mediastinal lymph nodes or directly into the thoracic duct
• Lateral diaphragmatic nodes: May drain into phrenic or hepatic lymph nodes depending on the pathway

Function

• Filters lymph from the diaphragm, pericardium, and adjacent visceral and parietal membranes
• Acts as a lymphatic bridge between thoracic and abdominal cavities
• Participates in the immune surveillance of both body cavities

Relations

• Superior nodes: In contact with the lungs, pericardium, and costal pleura
• Inferior nodes: In proximity to the liver (especially the bare area), kidneys, and suprarenal glands

Clinical Significance

• Metastasis: These nodes can be involved in malignancies of the liver, diaphragm, peritoneum, and pleura
• Spread of infection: Infections like peritonitis or pleuritis may track through the diaphragm via lymphatic channels
• Surgical consideration: Rarely targeted directly, but can be involved in hepatic or diaphragmatic tumor resections

Topographic Summary

• Location: On superior and inferior surfaces of the diaphragm
• Afferents: From diaphragm, pericardium, abdominal wall, liver, and pleura
• Efferents: To parasternal, posterior mediastinal, and thoracic duct
• Function: Lymphatic bridge between thoracic and abdominal cavities