Medial external iliac nodes

At a glance

English

Medial external iliac nodes

Latin (TA2)

Nodi iliaci externi mediales

System

Lymphatic

Region

Trunk

Side

Paired, left and right

About the medial external iliac nodes

The external iliac nodes follow the external iliac vessels along the pelvic brim, in lateral, intermediate and medial chains. The medial chain lies against the pelvic side wall below and medial to the external iliac vein, above the obturator nerve. At its lower end, just behind the inguinal ligament, sits the medial lacunar node near the femoral ring.

The chain rests on the fascia over obturator internus, below the vein and above the obturator vessels and nerve. The obliterated umbilical artery and the ureter pass medial to it as they run down and forward towards the bladder. This makes the area between the vein and the obturator nerve, often called the obturator fossa by surgeons, a single block of fat and nodes.

The chain receives lymph from the deep inguinal nodes, and therefore from the lower limb and the perineum, and directly from the lower anterior abdominal wall, the deep medial thigh and the bladder. Its efferent vessels pass up to the common iliac nodes, especially their medial and intermediate chains.

Because the bladder drains directly here, the medial chain is one of the most frequent first sites of spread from bladder cancer. It is the core of a standard pelvic lymph node dissection, in which the fat and nodes are cleared from under the external iliac vein while the obturator nerve is kept safe. Removing these nodes may lead to swelling of the leg or a collection of lymph in the pelvis.

Course and drainage

Begins at

Efferent vessels of the deep inguinal nodes, and direct vessels from the lower anterior abdominal wall, the deep medial thigh and the bladder.

Drains into

Efferent vessels pass to the common iliac nodes, mainly their medial and intermediate chains.

Drains

A relay for lymph from the lower limb, the lower abdominal wall and the bladder. A common first site of spread for bladder cancer and the centre of standard pelvic lymph node dissection.