Pararectal nodes

At a glance

English

Pararectal nodes

Latin (TA2)

Nodi pararectales

System

Lymphatic

Region

Trunk

Side

Single, on the midline

About the pararectal nodes

The pararectal nodes are small nodes in direct contact with the rectum. They lie on its muscular coat, embedded in the mesorectum, the layer of fat, vessels and lymph tissue that wraps the rectum and is enclosed by the thin mesorectal fascia. Most are found behind and beside the rectum, along the branches of the superior rectal artery.

They are the first nodes to receive lymph from the wall of the rectum. Lymph from the upper and middle rectum passes through them and then follows the superior rectal vessels upward to the inferior mesenteric nodes at the origin of the inferior mesenteric artery. Some lymph from the lower rectum runs instead with the middle rectal vessels to the internal iliac nodes. The anal canal below the pectinate line drains differently, to the superficial inguinal nodes.

These nodes matter greatly in rectal cancer. Because the tumour spreads first to the nodes in the mesorectum, the standard operation removes the rectum together with the whole mesorectum in its intact fascial envelope, so that all the pararectal nodes go with it. This technique, total mesorectal excision, greatly lowers the risk of the cancer coming back in the pelvis.

Before surgery, magnetic resonance imaging is used to look for enlarged or abnormal nodes in the mesorectum, and the number of involved nodes found in the specimen guides the stage and further treatment.

Course and drainage

Begins at

Afferent vessels from the wall of the rectum, mainly its upper and middle parts.

Drains into

Efferent vessels follow the superior rectal vessels to the inferior mesenteric nodes; some lower rectal lymph passes with the middle rectal vessels to the internal iliac nodes.

Drains

The first filter for lymph from the rectum. The first site of spread of rectal cancer, removed with the whole mesorectum at total mesorectal excision.