_______________________________________________________________________________________________________________________________ 4230 https://www.id-press.eu/mjms/index ID Design Press, Skopje, Republic of Macedonia Open Access Macedonian Journal of Medical Sciences. 2019 Dec 30; 7(24):4230-4238. https://doi.org/10.3889/oamjms.2019.366 eISSN: 1857-9655 Basic and Clinical Medical Researches in Vietnam Anatomical Characteristics of Facial Nerve Trunk in Vietnamese Adult Cadavers Tran Dang Khoa 1 , Nguyen Duy Bac 2 , Hoang Van Luong 2 , Tran Ngoc Anh 2 , Nguyen Thi Phuong 3 , Vu Thi Nga 4 , Toi Chu Dinh 5* 1 Department of Anatomy, Pham Ngoc Thach University of Medicine (PNTU), Ho Chi Minh City, Vietnam; 2 Department of Anatomy, Vietnam Military Medical University (VMMU), Hanoi, Vietnam; 3 NTT Hi-tech Institute, Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam; 4 Institute for Research and Development, Duy Tan University, Danang, Vietnam; 5 Department of Human and Animal Physiology, Faculty of Biology, Hanoi National University of Education, Hanoi, Vietnam Citation: Khoa TD, Bac ND, Luong HV, Anh TN, Phuong NT, Nga VT, Chu Dinh T. Anatomical Characteristics of Facial Nerve Trunk in Vietnamese Adult Cadavers. Open Access Maced J Med Sci. 2019 Dec 30; 7(24):4230-4238. https://doi.org/10.3889/oamjms.2019.366 Keywords: Facial nerve; Superior ramus; Inferior ramus; Mandibular angle; Retromandibular vein *Correspondence: Toi Chu Dinh. Department of Human and Animal Physiology, Faculty of Biology, Hanoi National University of Education, Hanoi, Vietnam. E-mail: chudinhtoi@hnue.edu.vn Received: 28-May-2019; Revised: 20-Sep-2019; Accepted: 21-Sep-2019; Online first: 15-Oct-2019 Copyright: © 2019 Tran Dang Khoa, Nguyen Duy Bac, Hoang Van Luong, Tran Ngoc Anh, Nguyen Thi Phuong, Vu Thi Nga, Toi Chu Dinh. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0) Funding: This research did not receive any financial support Competing Interests: The authors have declared that no competing interests exist Abstract BACKGROUND: In medical literature, there are few studies provided a precise and detailed description of the facial nerve rami and its branches. AIM: Identify several practical anatomic landmarks related to the facial nerve main trunk and its rami. METHODS: A descriptive study, 30 cadavers in the anatomy department of UPNT from October 2012 to April 2015. RESULTS: The average distance from the mandibular angle to the division of the facial nerve is 40.8 mm, and is 86.6% from range 36 – 50 mm. There is 86.7% case in which the facial nerve is in the lateral of the retromandibular vein, and there is a significant difference about both sides. Eighty percent of the case has the superior and inferior ramus in the lateral to the retromandibular vein. There are 2 cases in which the superior ramus makes the circle of the vein. Eighty percent of the facial nerve is in the lateral to the external carotid artery. CONCLUSION: The distance from the mandibular to the division of the facial nerve is longer. The relationship between the superior/inferior ramus and the retromandibular vein maybe not the same in both sides. In some cases, it makes the circle of the vein to cause some complication in the parotid gland surgery. Introduction In medical literature, even though many authors already have done many studies about the facial nerve anatomy on Caucasian and non- Caucasian race, specifically about its course through the parotid gland, its rami and its branching pattern to innervate its end-organ, none of them provided precise and detailed description about its rami and its branches [1], [2]. Also, they notice that the variability of the facial nerve origin and ramification proximal to the intraparotid course have an intimate anatomic relationship with other structures such as the digastricus, the mastoid process, the mandibular angle, the retromandibular vein, the external carotid artery, etc. [1], [3]. Therefore, achieving a basic understanding of the exact course of the facial nerve in the parotid gland and its rami is critical for every surgeon to prevent facial nerve injury in parotid gland- related surgeries. There are anatomic landmarks that help pinpoint the facial nerve trunk, e.g. mastoid process, posterior belly of the digastricus, tragal “pointer”, retromandibular vein, etc. [4]. The key to successfully locate the facial nerve trunk lies in those landmarks that act as reference points for the surgeons to predict the safety of nearby structures. Additionally, given that these reference points are fixed during surgery, they should be easily palpable and should permit surgeons to quickly, safely identify