Median sacral nodes

At a glance

English

Median sacral nodes

Latin (TA2)

Nodi sacrales mediani

System

Lymphatic

Region

Trunk

Side

Single, on the midline

About the median sacral nodes

The median sacral nodes are parietal pelvic nodes set on the pelvic surface of the sacrum, along the slender median sacral artery that runs down the midline from the back of the aortic bifurcation to the coccyx. On each side, further out, lie the lateral sacral nodes along the lateral sacral arteries. At the upper end, in front of the promontory, the group merges with the subaortic nodes of the common iliac chains.

The nodes lie in the presacral space, behind the rectum and the mesorectal fascia and in front of the bone. The presacral veins and the hypogastric nerves run in the same plane, and the sympathetic trunks descend just to either side. The nodes are few and small and cannot be felt from outside.

They drain the posterior pelvic wall and the back of the rectum. Lymph leaving them passes upward to the common iliac nodes, mainly the medial chain and the subaortic nodes below the bifurcation, before reaching the lumbar chain.

In rectal cancer, nodes behind the rectum are an important path of spread, and those in the presacral space may be seen on scans when staging the tumour. Surgery that removes the rectum with its surrounding fat works in the plane just in front of these nodes, and great care is needed with the presacral veins, which can bleed heavily.

Course and drainage

Begins at

Afferent vessels from the posterior pelvic wall and the posterior aspect of the rectum.

Drains into

Efferent vessels pass to the common iliac nodes, mainly the medial chain and the subaortic nodes.

Drains

Filters lymph from the back of the pelvis and the rectum. A route for spread of rectal cancer, seen on staging scans and relevant to surgery in the presacral plane.