Intrapulmonary nodes

At a glance

English

Intrapulmonary nodes

Latin (TA2)

Nodi intrapulmonales

System

Lymphatic

Region

Whole body

Side

Single, on the midline

About the intrapulmonary nodes

The intrapulmonary nodes are the most peripheral lymph nodes of the lung. They sit within the lung tissue itself, mostly at the points where lobar and segmental bronchi branch, alongside the accompanying branches of the pulmonary artery. They form the first station for lymph leaving the lung, before it reaches the bronchopulmonary nodes at the hilum.

The lymph vessels that feed them are arranged in two separate networks. A superficial plexus lies just beneath the visceral pleura over the surface of each lung. A deep plexus travels inward with the bronchi and the pulmonary vessels; around the larger airways it has two layers, one under the lining mucosa and one outside the bronchial wall, while around the smaller airways it becomes a single network. These vessels reach the bronchioles but stop short of the alveoli, whose walls carry no lymphatics. The two plexuses have few connections with each other except near the hilum.

Lymph from the deep plexus runs back along the bronchi and vessels, passing through the intrapulmonary nodes and then the bronchopulmonary nodes, before reaching the tracheobronchial nodes around the main bronchi and the lower trachea. Vessels of the superficial plexus wind around the borders of the lung and the edges of its fissures to collect at the hilum.

In lung cancer these nodes, with the hilar nodes, make up the nearest nodal station, and their involvement is an important step in staging, since disease confined to them is often still suitable for surgery. They also collect inhaled dust and carbon, and in city dwellers and smokers they are often stained black. Small intrapulmonary nodes can appear on CT as tiny rounded spots near the pleura or fissures, where they must be told apart from early tumours.

Course and drainage

Begins at

Afferent vessels of the deep lymphatic plexus of the lung, running along the bronchi and the branches of the pulmonary artery.

Drains into

Efferent vessels pass to the bronchopulmonary (hilar) nodes and then to the tracheobronchial nodes.

Drains

The first filter for lymph from the lung tissue. A key early station in lung cancer staging; they also store inhaled dust and may be seen as small spots on CT.