ANATOMY OF THE BRONCHIAL TREE

Abstract

THE HOMOLOGUES found in the study of comparative anatomy fortify opinion as to the significance of any bronchopulmonary segment in the common pattern in the mammalian lung and discount dogmatism as to the final emergence of any particular type in the human lungs. The illustration of Willis¹(1622-1675) depicts a diagram of a lobe of the lung, showing its subdivisions (fig. 1). It closely resembles the illustration by Huntington²(fig. 2). It is obvious from a study of comparative anatomy that some of the branches of the embryonic lobar stem bronchus disappear or fuse with others or become aggrandized to take over the areas whose segments have disappeared in the formation of the pattern of the lung of an individual of the species. The question of the entity and nomenclature of the segments of the upper lobe, a problem chiefly concerned with the separate entities of the axillary and anterior