The avian bronchial arteries: species variations.

The bronchial arteries arose from the oesophagotracheobronchial branches of the common carotid arteries. In the goose, duck, Muscovy duck, and turkey several small bronchial arteries supplied the whole length of each primary bronchus, including the orifices of the secondary bronchi. In the guinea-fowl and quail similar bronchial arteries supplied only the extrapulmonary part of the primary bronchus. In the pigeon a single true bronchial artery supplied the extrapulmonary part of each primary bronchus; this pair of bronchial arteries arose asymmetrically from a common bronchial trunk derived from the left oesophagotracheobronchial artery only. In this species, and in the guinea-fowl and quail, the intrapulmonary part of the primary bronchus was supplied by the pulmonary artery. There were no branches to the exchange tissue in any species. In all species the bronchial veins of the extra-pulmonary part of the primary bronchus drained via oesophageal veins, whereas those of the intrapulmonary part emptied into branches of the pulmonary vein.