Ian S McLennan1, Yih Harng Chong2,3. 1. Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand. ian.mclennan@otago.ac.nz. 2. Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand. 3. Department of Medicine, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand.