Intermediate common iliac nodes

At a glance

English

Intermediate common iliac nodes

Latin (TA2)

Nodi iliaci communes intermedii

System

Lymphatic

Region

Trunk

Side

Single, on the midline

About the intermediate common iliac nodes

The common iliac nodes surround the common iliac artery from the bifurcation of the aorta down to the point where the artery divides into its external and internal branches. They are arranged in chains named by their relation to the vessels: a lateral chain on the outer side, a medial chain on the inner side, and an intermediate chain hidden behind the artery and vein.

The intermediate nodes lie in the groove behind the vessels, against the front of the lumbosacral junction and the medial edge of psoas major. In this deep position they are close to the lumbosacral trunk and the obturator nerve as these run down into the pelvis, and to the sympathetic trunk on the side of the vertebral bodies. Because they are covered by the artery and vein, they are the hardest of the group to reach at surgery.

They receive lymph that has already passed through the external and internal iliac nodes, and so collect, at second hand, from the lower limb, the lower abdominal wall and much of the pelvis, including the bladder and rectum. From here lymph rises to the lumbar nodes beside the aorta and inferior vena cava.

Spread of pelvic cancers, such as those of the bladder or rectum, often reaches the common iliac chain once the nodes lower down are involved, so its state helps define how far the disease has travelled. Surgeons clearing these nodes must lift the common iliac vessels to reach the intermediate chain, taking care of the large veins and nerves beneath.

Course and drainage

Begins at

Efferent vessels from the external iliac and internal iliac nodes, carrying lymph from the lower limb, lower abdominal wall and pelvic organs.

Drains into

Efferent vessels run upwards to the lumbar nodes around the aorta and inferior vena cava.

Drains

A second relay for lymph from the pelvis and lower limb. Their involvement marks spread of a pelvic cancer beyond the first nodes, which affects staging and the extent of lymph node dissection.