Surgical anatomy of the facial nerve in Chinese mastoids

Since racial differences in mastoid morphology exist, there may be racial d ifferences in the surgical anatomy of the facial nerve in the mastoid. Thir ty Chinese adult temporal bones were dissected. The facial nerve in the mas toid coursed vertically (60.0%), anteriorly (33.3%) and posteriorly (6.7%) in the sagittal plane. In the coronal plane, it coursed vertically (46.7%) and laterally (53.3%). The chorda tympani was found to have extratemporal o rigin in 53.3% and for the rest, the distance of its origin from the stylom astoid foramen averaged 3.17 mm (range 0.5-6.0 mm). The mean dimension of t he extended facial recess was 4.40 mm (range 3.0-6.0 mm). The facial nerve was at a mean of 3.15 mm (range 2.0-5.0 mm) posterior to the most posterior point of the tympanic annulus and partially crossed the tympanic annulus f rom medial to lateral at this point. In conclusion, the typical surgical an atomy of the mastoid facial nerve as described in the Western literature ma y not apply to the Chinese.