Subgross Pulmonary Anatomy of the Rabbit, Rat, and Guinea Pig, with Additional Notes on the Human Lung1, 2, 3

Subgross anatomy is concerned with those finer structures whose morphologic characteristics and relationships are best revealed through the use of the dissecting microscope and injection techniques. These structures are visualized less well by the eye itself or through the compound microscope using commonly available magnifications and ordinary histologic techniques. In previous investigations of 8 mammalian species, including man, three basic subgross lung patterns were observed (1, 2). They were classified arbitrarily as subgross types I, II, and III on the basis of included species being more similar to each other and not on a basis of absolute identity. Type I was found in the cow, lamb, and pig; type II, in the dog, cat, and monkey; and type III, in the horse and in man. Marked differences in vascular and parenchymal morphology were encountered between each type. In type I, secondary lobules are very well defined. They are absent in type II, and imperfectly defined in type III. The pleura and interlobular septa are thick in types I and III.