Lateral sacral nodes

At a glance

English

Lateral sacral nodes

Latin (TA2)

Nodi sacrales latérales

System

Lymphatic

Region

Trunk

Side

Paired, left and right

About the lateral sacral nodes

The lateral sacral nodes are parietal pelvic nodes that rest on the concave pelvic surface of the sacrum. They lie on each side of the midline close to the row of anterior sacral foramina, alongside the lateral sacral arteries that run down from the internal iliac artery. A median sacral group lies between the two sides, along the median sacral artery.

In this position the nodes sit behind the rectum and its surrounding fat, separated from it by the presacral fascia, and just in front of the sacral nerves as they emerge from the foramina to form the sacral plexus. They are small and usually few, and they are not felt from the surface, though large ones can sometimes be reached on rectal examination.

Lymph comes to them from the posterior wall of the pelvis and from the rectum and the other pelvic viscera that lie against the back wall. Their efferents pass to the internal iliac nodes and to the common iliac nodes, sometimes reaching the subaortic nodes below the aortic bifurcation.

In rectal cancer, spread can travel backwards and outwards along these lateral routes as well as upwards along the mesorectum. Enlarged sacral nodes on imaging may therefore change the plan for surgery or radiotherapy. Removing them needs care because of the presacral veins and the sacral nerves close by.

Course and drainage

Begins at

Afferent vessels from the posterior pelvic wall and from the rectum and other pelvic organs lying against the sacrum.

Drains into

Efferent vessels run to the internal iliac nodes and the common iliac nodes.

Drains

Filters lymph from the back of the pelvis and the rectum. A lateral route for spread of rectal cancer, which can alter the plan for surgery or radiotherapy.