Topography of the Branching Patterns of the Facial Nerve in Korean

Kwak, Hyun Ho; Park, Hyun Do; Youn, Kwan Hyun; Hu, Kyung Seok; Koh, Ki Seok; Han, Seung Ho; Kim, Hee Jin

Abstract

This study demonstrates the anatomical relationships and variability of the facial nerve trunk and branches with emphasis on intraparotid connections between divisions. Microsurgical dissections were performed on 30 Korean halfheads. The facial nerve trunk was exposed, depth from the skin surface to the stylomastoid foramen (21.0+/-3.1 mm) and distance between the stylomastoid foramen and the bifurcation point of temporofacial (upper) and cervicofacial (lower) divisions (13.0+/-2.8 mm) were measured. In 26 out of 30 dissections, the facial nerve terminated in a bifurcation into two main divisions, and in four cases, the nerve ended in a trifurcation pattern. According to the origin of the buccal division, branching patterns of the facial nerve were classified into 6 categories. A buccal division was originated from the upper and lower divisions (type I, 13.8%), from the two main and zygomatic divisions (type II, 44.8%), from the two main and marginal mandibular divisions (type III, 17.3%), from the two main, zygomatic and mandibular divisions (type IV, 17.3%), from the lower, zygomatic and mandibular divisions (type V, 3.7%), and from the upper, zygomatic and mandibular divisions (type VI, 3.7%). These details of facial nerve anatomy suggest surgical procedures such as tumor resection, facial nerve reconstruction, and facelift.