Observations on the normal anatomy of the bronchial arteries.

The existence of systemic arteries to the lungs has been known for many centuries. Ruysch (1732) claimed to be the first to have described the bronchial arteries, but Galen had already done so in the second century A.D. During the nineteenth century the anatomy of the bronchial arteries was studied in detail and their possible function considered. Reisseisen and von Soemmering (1808) defined the bronchial arteries as " vasa nutritiva " of the lungs, and showed that they accompanied the bronchi. Le Fort (1858) showed that the bronchial arteries continue along the bronchial tree as far as the respiratory bronchioli. Von Luschka (1863) drew attention to the ramification of the bronchial arterioles in the bronchial mucosa and suggested that the capillaries of the bronchial arterioles communicated near the alveolar ducts with those derived from the pulmonary arteries. Virchow (1856) showed that occlusion of a lobar pulmonary artery branch did not result in necrosis of the lobe. He concluded therefore that the viability of the lobe,did not depend on the pulmonary artery, but was maintained by the bronchial arteries. Rindfleisch (1878) considered the bronchial arteries to be end arteries. Kuttner (1878), by dye injections in rabbit lungs, showed that the terminal branches of the pulmonary arteries were nowhere in communication with vessels of a similar calibre, and concluded that communication between the pulmonary artery bed and the bronchial arteries, if it existed, must be capillary only. Zuckerkandl (1881 and 1883) demonstrated that the bronchial arteries supplied the visceral pleura in man, and thought that the capillaries of the pulmonary and bronchial arteries were in communication. Miller (1947), at the beginning of this century, described the course of the bronchial arteries. He showed that they ran from the aorta to the main bronchi and followed these distally to the hila. There they divided and continued in the walls of the bronchi as far as the alveolar ducts. From the fibrous tunic, in which an arterial plexus was formed, small branches penetrated the muscle layer to reach the tunica propria of the bronchus and then continued to run in the long axis of the bronchus. Miller did not think that the problem of anastomosis between the two circulations had been adequately studied by previous workers, and contended that the use of a