Superior Mesenteric Lymph Nodes
Superior mesenteric nodes receive lymph from midgut structures and drain into the cisterna chyli.
The superior mesenteric lymph nodes are a major group of preaortic lymph nodes located around the origin and along the branches of the superior mesenteric artery (SMA). They are responsible for draining lymph from all organs derived from the embryological midgut, including the distal duodenum, small intestine, cecum, ascending colon, and the proximal two-thirds of the transverse colon.
Structure
These nodes are classified into three major subdivisions based on their proximity to the SMA and its branches:
| Subdivision | Location | Drains |
|---|---|---|
| Mesenteric nodes | Within the mesentery of the jejunum and ileum | Jejunum and ileum |
| Ileocolic and right colic nodes | Along ileocolic and right colic arteries | Ileum, cecum, appendix, ascending colon |
| Middle colic nodes | Along the middle colic artery | Proximal 2/3 of the transverse colon |
These subdivisions send afferent lymph to intermediate and central superior mesenteric nodes located near the origin of the SMA, which in turn drain into the intestinal lymphatic trunk.
Location
The superior mesenteric lymph nodes are located:
- Surrounding the SMA at the L1 vertebral level
- Within the root of the mesentery and mesocolon
- Anterior to the abdominal aorta, between the pancreas and mesentery
Function
The superior mesenteric lymph nodes serve as critical filtration and immunologic relay stations for the midgut:
- Lymph drainage: Receive lymph from the distal duodenum, small bowel, cecum, appendix, and proximal large intestine
- Immune response: Act as sites for lymphocyte activation and antigen processing
- Central relay: Drain lymph toward the intestinal trunk and eventually to the cisterna chyli and thoracic duct
Clinical Significance
These nodes are commonly involved in gastrointestinal and systemic conditions:
- Mesenteric lymphadenitis: Inflammatory enlargement of nodes, often mimicking appendicitis in children
- Crohn’s disease: Chronic inflammation of the midgut may lead to lymph node hyperplasia and fibrosis
- Small and large bowel cancers: Midgut-derived tumors may metastasize to these nodes; involvement affects staging and treatment
- Lymphoma: Can present as bulky mesenteric adenopathy involving these nodes
- Imaging and biopsy: Enlarged nodes often detected on CT or ultrasound; may be sampled in persistent or suspicious cases
The superior mesenteric lymph nodes play a central role in the immune and lymphatic management of midgut organs. Their anatomical alignment with arterial branches and predictable drainage pathways make them critical in both clinical evaluation and surgical oncology.
Last updated on May 9, 2025
