Abstract
Twenty dog lungs were examined. The right pulmonary artery runs across the ventral side of the right cranial lobe bronchiole, then across the dorsal side of the right middle lobe bronchiole. Thereafter, the right pulmonary artery runs along the dorso-lateral side of the right bronchus. During its course, the right pulmonary artery gives off arterial branches that run mainly along the dorsal or lateral side of each bronchiole. The left pulmonary artery runs across the dorsal side of the left middle lobe bronchiole, and thereafter has the same distribution as that in the right lung. The pulmonary vein runs mainly along the medial or ventral side of the bronchiole, and between the bronchioles. In the right lung, the right cranial and middle lobe veins form a short common trunk, when enter the left atrium. The right accessory lobe vein enters the right caudal lobe pulmonary venous trunk. The right caudal lobe pulmonary venous trunk enters the left atrium. In the left lung, the left middle lobe vein has two branches. Both enter the left atrium, forming a short common trunk. In addition to these veins, the left caudal lobe pulmonary venous trunk enters the left atrium.
