The pulmonary branches of the vagus nerve

Vagus nerve

The vagus nerve , also called pneumogastric nerve or cranial nerve X, is the tenth of twelve paired cranial nerves...

can be divided into two groups: anterior and posterior.

Anterior

The Anterior Bronchial Branches (rami bronchiales anteriores; anterior or ventral pulmonary branches), two or three in number, and of small size, are distributed on the anterior surface of the root of the lung

Lung

The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...

.

They join with filaments from the sympathetic

Sympathetic nervous system

The sympathetic nervous system is one of the three parts of the autonomic nervous system, along with the enteric and parasympathetic systems. Its general action is to mobilize the body's nervous system fight-or-flight response...

, and form the anterior pulmonary plexus.

Posterior

The Posterior Bronchial Branches (rami bronchiales posteriores; posterior or dorsal pulmonary branches), more numerous and larger than the anterior, are distributed on the posterior surface of the root of the lung; they are joined by filaments from the third and fourth (sometimes also from the first and second) thoracic ganglia of the sympathetic trunk, and form the posterior pulmonary plexus.

Branches from this plexus accompany the ramifications of the bronchi through the substance of the lung.