Medial common iliac nodes

At a glance

English

Medial common iliac nodes

Latin (TA2)

Nodi iliaci communes mediales

System

Lymphatic

Region

Trunk

Side

Single, on the midline

About the medial common iliac nodes

The common iliac nodes are grouped around the common iliac vessels into lateral, intermediate and medial chains. The medial chain runs along the inner side of each common iliac artery, in the triangle that opens out below the bifurcation of the aorta. Nodes in the very apex of this triangle, against the fifth lumbar vertebra and the sacral promontory, are often described as subaortic or promontorial nodes.

In this position the nodes lie behind the peritoneum, in front of the body of the fifth lumbar vertebra and the intervertebral disc below it. The left common iliac vein crosses beneath the right artery here, and the superior hypogastric plexus of autonomic nerves descends over the front of the promontory between the two chains. The sigmoid mesocolon and the upper rectum lie just in front on the left.

The medial chain collects from the internal iliac nodes and the sacral nodes, and from the medial chain of the external iliac nodes. It therefore receives, at second hand, much of the lymph of the pelvic organs, including the bladder and rectum. Its efferents rise to the lumbar nodes around the aorta and inferior vena cava.

When a pelvic cancer, such as one of the bladder or rectum, spreads beyond the nodes of the pelvic wall, this chain is one of the next stops, so it is examined in staging and cleared in extended pelvic dissection. Surgeons operating here protect the hypogastric nerves on the promontory, since injury can disturb bladder control.

Course and drainage

Begins at

Efferent vessels from the internal iliac nodes, the sacral nodes and the medial external iliac nodes, carrying lymph from the pelvic viscera and walls.

Drains into

Efferent vessels pass up to the lumbar nodes beside the aorta and inferior vena cava.

Drains

A second relay for lymph from the pelvic organs. Their involvement shows a pelvic cancer has spread beyond the pelvic wall nodes, and they are taken in extended pelvic dissection.