Topography of the major superficial lymph nodes and their efferent lymph pathways in the koala (Phascolarctos cinereus).

The koala has an inguinoaxillary lymph trunk on either side of the ventral midline, and this carries efferent lymph from the superficial inguinal lymph node directly to the deep axillary lymph node. The superficial lymph nodes are large and soft compared with those of the domestic species, and each lymph centre usually contains only one or two large lymph nodes. Koalas have a rostral mandibular lymph node which has not been described in other species, but lack popliteal and subiliac lymph nodes. The superficial lymph nodes which are readily palpable in the live koala are the facial, rostral mandibular, mandibular, superficial axillary and superficial inguinal. All superficial lymph pathways terminate at the confluence of the common jugular and subclavian veins.