1. Department of Anatomy Tokyo Dental College Tokyo Japan
2. Department of Histology and Embryology Tokyo Dental College Tokyo Japan
3. Department of Otolaryngology‐Head and Neck Surgery Tohoku University Graduate School of Medicine Sendai Japan
4. Division of Internal Medicine Jikou‐kai Clinic of Home Visits Sapporo Japan
5. Emeritus professor, Department of Anatomy Akita University School of Medicine Akita Japan