Intraorbital Anatomy of the Koala (Phascolarctos cinereus)
R. C. KEMPSTER, B. J. BANCROFT, AND L. W. HIRST*
Division of Ophthalmology, Department of Surgery, Princess Alexandra Hospital, Woolloongabba, Queensland, Australia
This is the ﬁrst documented study of the anatomical details of the contents of the normal koala orbit, excluding the bulbus oculi. Baseline data were established which are necessary for understanding and treating ocular disease in the koala (Phascolarctos cinereus). The anatomy of the orbital contents of the koala were examined and described from animals that presented dead or were euthanized for humane reasons. Dissections of the orbital cavity were performed under magniﬁcation. Polymethyl methacrylate (PMMA) casts of the nasolacrimal system and the vascular supply of the orbit were also made in order to study these systems. The superﬁcial lymphatic drainage of the conjunctival tissues was studied by subcutaneous injection of Evan’s Blue into the palpebral conjunctiva of a freshly deceased animal,and by Microﬁl casts of the efferent lymphatics. In general,the orbital contents of the koala are consistent with those of other carnivorous polyprotodont and herbivorous diprotodont marsupials.