1. Department of Histology and Cytology; Faculty of Veterinary Medicine; Zagazig University; Zagazig 44519 Egypt
2. Laboratory of Anatomy; Department of Biomedical Sciences; Graduate School of Veterinary Medicine; Hokkaido University; Sapporo 060-0818 Japan
3. Office for Faculty Development and Teaching Enriched Veterinary Medicine; Graduate School of Veterinary Medicine; Hokkaido University; Sapporo 060-0818 Japan