Plexus (pulmonary, anatomy)

The pulmonary plexuses are the sites of convergence of autonomic fibres which supply the lung. They are in continuity with the cardiac plexuses, which lie superiorly, and the oesophageal plexuses, which lie posterosuperiorly.

They are sited anterior and posterior relative to each lung root. They are in close proximity to the pulmonary arteries and, as they branch laterally they ramify their nerve fibres in association with the outer walls of diverging pulmonary arteries and arterioles.

The passage of fibres from the cardiac plexus is inferiorly, anterior to the trachea and posterior to the aortic arch. The pulmonary plexus also receives autonomic fibres directly from two other sources.

• parasympathetic:
  • right vagus nerve: descends posteroinferiorly on the trachea; divides posterior to the trachea to give pulmonary and oesophageal plexuses; pulmonary plexus passes anteriorly to root of the lung
  • left vagus nerve: descends anteriorly to arch of aorta, gives off recurrent laryngeal branch and then fibres diverge anteriorly to supply the left pulmonary arterial plexus
• sympathetic: rami of the superior four thoracic ganglia pass anteriorly around the posterior thoracic cage to merge on the lateral walls of the oesophagus. They supply nerve fibres to the pulmonary plexus from the region dorsal to the tracheal bifurcation.