Pulmonary venous compartment of the airways circulation.

Bronchial circulation has three components: a systemic arterial component represented by the bronchial arteries; a pulmonary venous component represented by the pulmonary veins; and a systemic venous component represented by the bronchial veins. We have used vascular casting, microscope dissection coupled with tracers and light microscopy to define the detailed anatomy of the pulmonary venous compartment of the bronchial circulation. We have found that the extrapulmonary drainage territory of the pulmonary veins correlate with the forming pattern of the right superior pulmonary vein. In the case of a large apical venous trunk, pulmonary veins drain the venous blood of the main bronchia, terminal portion of the trachea and of the tracheobronchial lymph nodes. In the case of the systemic venous drainage of the extrapulmonary airways, we constantly found a pulmonary component which drains the venous blood from the subcarinal lymph nodes and the medial side of the main bronchia.