The masseteric nerve: An anatomical study in Thai population with an emphasis on its use in facial reanimation.

Background: The use of the masseteric nerve has been escalated as a donor nerve for facial reanimation in facial palsy patient (Wang et al., 2014; Manktelow et al., 2006; Klebuc, 2011; Bianchi et al., 2012; Zuker et al., 2000; Bae et al., 2006; Terzis, Konofaos, 2013; Terzis, Olivares, 2009; Bianchi et al., 2014). Previous studies had been done in Euro-Caucasian cadavers (Kaya et al., 2014). However, difference in anatomical details does exist between Asian and Euro-Caucasian population (Tzou et al., 2005; Farkas et al., 2005). In this study, we have conducted a detailed anatomical study of masseteric nerve in adult Thai cadavers which might elaborate better details of masseteric nerve anatomy in Asian population.

Methods: Twenty eight hemifaces from 14 adult Thai non-formaldehyde preserved soft cadavers were used in this study. The anatomical pathway of the masseteric nerve was defined relating to four surgical landmarks which are auricular tragus, zygomatic arch, posterior border of the temporomandibular joint, and alar base.

Results: The suitable starting area for the masseteric nerve dissection is 3.7 ± 0.4 cm anterior to the auricular tragus at the level of 0.8 ± 0.2 cm inferior to the zygomatic arch. The nerve was found 1.1 ± 0.2 cm deep to the superficial surface of the masseteric fascia and 1.7 ± 0.2 cm anterior to the posterior border of the temporomandibular joint. The point where the nerve giving off its first branch as it courses distally is 7.3 ± 0.7 cm from the ipsilateral alar base. The mean diameter of this nerve is 1.59 ± 0.42 mm.

Conclusion: The anatomy of the masseteric nerve during its course in the muscle is consistent. In our study, the details of its anatomy is slightly different from the previous works which were performed in the Euro-Caucasian cadavers.