Richard Drake, PhD, FAAA, Director of Anatomy, Professor of Surgery, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, Ohio, USA, A. Wayne Vogl, PhD, FAAA, Professor of Anatomy and Cell Biology, Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada and Adam W. M. Mitchell, MB BS, FRCS, FRCR, Consultant Radiologist, Chelsea and Westminster Hospital, Honorary Senior Lecturer, Imperial College, London, UK