Obturator nodes

At a glance

English

Obturator nodes

Latin (TA2)

Nodi obturatorii

System

Lymphatic

Region

Trunk

Side

Paired, left and right

About the obturator nodes

The obturator nodes are a small group of pelvic wall nodes set along the obturator artery, which runs forward on the side wall of the lesser pelvis from the internal iliac artery to the obturator canal at the top of the obturator foramen. They are often counted with the internal iliac nodes, though in practice they merge with the lowest nodes of the medial external iliac chain.

The nodes rest on the fascia of obturator internus, below the external iliac vein and alongside the obturator nerve, which runs with the artery to the canal. Medial to them lie the ureter and the bladder. The fat containing these nodes and the nerve fills a space that surgeons call the obturator fossa.

Lymph comes to them from the bladder and the pelvic viscera beside it, and from the deep tissues of the medial thigh, whose vessels follow the obturator artery back through the canal. Their efferents pass to the internal iliac nodes and to the medial external iliac nodes, then on to the common iliac nodes.

The obturator nodes are among the first sites reached by bladder cancer and are always cleared in pelvic lymph node dissection. Here the surgeon must find and spare the obturator nerve, whose injury weakens the adductor muscles of the thigh. Enlarged nodes in the obturator fossa are a common finding on staging scans of pelvic tumours.

Course and drainage

Begins at

Afferent vessels from the bladder and adjacent pelvic viscera and from the deep medial thigh by way of the obturator canal.

Drains into

Efferent vessels pass to the internal iliac nodes and the medial external iliac nodes, then the common iliac nodes.

Drains

Filters lymph from the bladder region and the deep medial thigh. They are an early site of spread for bladder cancer, removed in pelvic dissection with care for the obturator nerve.