fereshteh talebpour amiri department of anatomy, faculty of medicine, mazandaran university of medical sciences, sari, ir iran fatemeh fadaei fathabadi department of anatomy, faculty of medicine, mazandaran university of medical sciences, sari, ir iran mahnaz mahmoudi rad skin research centre, shahid beheshti university of medical sciences, tehran, ir iran; skin research centre, shahid beheshti university of medical sciences, tehran, ir iran. tel: +98-2122741512, fax: +98-2122027147 abbas piryae department of anatomy, faculty of medicine, mazandaran university of medical sciences, sari, ir iran azar ghasemi department of pathology, faculty of medicine, mazandaran university of medical sciences, sari, ir iran alireza khalilian department of biostatistics and social medicine, faculty of medicine, mazandaran university of medical sciences, sari, ir iran