Paracolic superior mesenteric nodes

At a glance

English

Paracolic superior mesenteric nodes

Latin (TA2)

Nodi mesenterici superiores paracolici

System

Lymphatic

Region

Trunk

Side

Single, on the midline

About the paracolic superior mesenteric nodes

The lymph of the colon passes through a series of node groups that follow its blood supply. The paracolic nodes are the first of these, set on or just beside the colon wall. Those belonging to the superior mesenteric territory line the ascending colon, the right colic flexure and most of the transverse colon; beyond the left flexure the paracolic nodes drain instead towards the inferior mesenteric nodes.

The nodes are small, flat and numerous, and they lie along the marginal artery, the continuous vessel that joins the colic arteries along the inner border of the colon. On the ascending colon they sit behind the peritoneum, while on the transverse colon they lie within the transverse mesocolon close to its attachment to the bowel. The fatty tags on the colon surface, the omental appendices, are nearby.

They receive lymph from the wall of the colon by short vessels from its lining and muscle. Their efferents run inward along the right colic, middle colic and ileocolic arteries to the intermediate nodes on those vessels, and then to the main nodes at the root of the superior mesenteric artery.

Because they lie next to the bowel, these nodes are usually the first station reached by colon cancer, and nodes positive here already change the stage of the disease. They come away with the colon and its mesentery at a right or extended right hemicolectomy, and the pathologist examines them to decide whether further treatment is needed.

Course and drainage

Begins at

Afferent vessels from the wall of the ascending colon, the right colic flexure and the transverse colon.

Drains into

Efferent vessels pass to the ileocolic, right colic and middle colic nodes, then to the superior mesenteric nodes.

Drains

The first filter for lymph from the right and transverse colon. Often the first site of spread of colon cancer, so they are removed with the bowel and examined for staging.