Intestinal Lymphatic Trunk

The intestinal lymphatic trunk is a major lymphatic vessel that collects lymph from the gastrointestinal tract and associated organs and drains it into the cisterna chyli. It serves as the final conduit for lymph from the preaortic lymph nodes (celiac, superior mesenteric, and inferior mesenteric groups), which receive lymph from the foregut, midgut, and hindgut respectively. The intestinal trunk plays a crucial role in transporting nutrient-rich and immune-filtered lymph toward the systemic circulation via the thoracic duct.

Structure

The intestinal trunk is typically a single but occasionally paired lymphatic vessel that lies in the upper abdomen, posterior to the peritoneum. It begins as a convergence of efferent vessels from the preaortic lymph nodes and runs upward to drain into the cisterna chyli — a dilated sac that marks the origin of the thoracic duct.

Key Tributaries:

Location

The intestinal trunk lies in the retroperitoneum, between the abdominal aorta and the vertebral column, often at the level of the L1–L2 vertebrae. It joins the cisterna chyli near the origin of the thoracic duct, close to the right crus of the diaphragm.

Function

The intestinal lymphatic trunk performs several vital roles:

• Lymph transport: Collects filtered lymph from the entire gastrointestinal tract and sends it to the thoracic duct for return to venous circulation
• Lipid absorption: Transports chyle (lymph rich in absorbed lipids) from intestinal lacteals
• Immunological routing: Passes lymph that has been exposed to immune processing in mesenteric and preaortic nodes

Clinical Significance

While the intestinal trunk is not commonly evaluated directly in clinical imaging, it plays a critical background role in lymphatic and metabolic physiology:

• Lymphatic obstruction: Tumors or fibrosis obstructing the intestinal trunk or cisterna chyli can result in chylous ascites (accumulation of lipid-rich lymph in the peritoneal cavity)
• Gastrointestinal cancer staging: Involvement of the preaortic lymph nodes feeding into the trunk can affect staging and surgical planning in gastric, pancreatic, and colorectal cancers
• Lymphatic mapping: Advanced imaging (lymphangiography) may trace lymphatic pathways for understanding or managing conditions like lymphoma or metastatic spread
• Trauma or post-surgical leakage: Injury to mesenteric lymphatics may cause chylous leakage, indirectly affecting trunk flow

The intestinal lymphatic trunk is an essential component of the abdominal lymphatic system, functioning as the final collector for gastrointestinal lymph. Though rarely visualized directly, it plays a key role in both digestion (via lipid transport) and immunity (via lymph filtration), ultimately delivering processed lymph to the thoracic duct and venous circulation.