Topography of the major superficial lymph nodes and their efferent lymph pathways in the koala (Phascolarctos cinereus)*
JONATHAN J. HANGER AND TREVOR J. HEATH
Department of Anatomy, University of Queensland, St Lucia, Brisbane, Queensland, Australia 4067
Although disease has long been recognised as a significant cause of mortality in koalas, virtually no information is available on their immune system and its responses to disease. The peculiar susceptibility of koalas to disease and the apparent incompetence of their immune systems, particularly in combating infections, has led some research workers to suggest that the immune response in these animals may be retarded in some way (Brown et al. 1987; Brown, 1988). Virtually no information, however, is available on the lymph nodes or vessels, or other aspects of the immune system, in koalas. Furthermore, the lymphatic system of other marsupials has only been described in any detail in the American opossums (Didelphys azarae and Didelphys marsupialis) (Zimmerman, 1940; Azzali & Di Dio, 1965), and the kangaroo (Macropus spp.) (Hopwood, 1980, 1988). The aim of this study was to describe the topographical anatomy of the major superficial lymph nodes and lymph pathways in koalas to their termination in the great veins. This was achieved by gross dissection, and by using Evans Blue dye and Microfil casts.