1. Department of Anatomy, Histology and Embryology; Yanbian University Medical College; Yanji China
2. Division of Surgery; Doto Hospital; Sapporo Japan
3. Division of Internal Medicine; Iwamizawa Asuka Hospital; Iwamizawa Japan
4. Division of Colon and Rectal Surgery; Shizuoka Cancer Center Hospital; Susuno, Shizuoka Japan
5. Department of Anatomy; Tokyo Dental College; Tokyo Japan