1. Department of Basic Medical Sciences, College of Medicine, King Saud bin Abdulaziz University for Health Sciences, Mail Code 3127, P.O. Box 3660, Riyadh 11481, Saudi Arabia
2. Anatomy Department, Faculty of Medicine, University of Khartoum, P.O. Box 102, Khartoum 11111, Sudan
3. Department of Anatomy, Faculty of Dentistry, University of Medical Sciences and Technology, P.O. Box 12810, Khartoum 11111, Sudan