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Updated: Aug 5, 2026
In Vivo Morphometric Analysis of Human Cranial Nerves Using Magnetic Resonance Imaging in Menière's Disease Ears and Normal Hearing Ears
Published on: February 21, 2018
Radiologic detectability and anatomic course of Arnold's nerve on temporal bone HRCT: A cross-sectional study
Masato Suzuki1, Makiko Obara2, Iori Kusaka1
1Department of Otolaryngology-Head-Neck Surgery, Iwate Medical University School of Medicine, 2-1-1 Idai Dori, Yahaba, Iwate, 028-3695, Japan.
Purpose:
To determine the radiologic detectability of the auricular branch of the vagus nerve (ABVN, Arnold's nerve) on temporal bone high‑resolution CT (HRCT), classify its course relative to the chorda tympani, and describe age‑ and sex‑related distributions.
Methods:
We retrospectively reviewed clinical temporal bone HRCTs obtained at a tertiary center (2019-2023). The cohort comprised 958 patients and 1854 ears after exclusions. ABVN positivity required a continuous osseous canal from the jugular fossa (mastoid canaliculus), crossing the facial canal, toward the tympanomastoid fissure. The crossing height relative to the chorda tympani defined Types A-C. Distances to surgical landmarks were measured.
Results:
ABVN was identified intraosseously in 255/1854 ears (13.8%). Detection by sex: 132/943 (14.0%) in males; 123/911 (13.5%) in females. By age: 38 ears (< 20 years, 8.7%); 217 ears (≥ 20 years, 15.3%). Course classification: A 101 (40%), B 150 (59%), C 4 (1%). Intraosseous bifurcation occurred in ~ 6% of positive ears. Mean measurements: mastoid canaliculus 6.4 mm; second genu to ABVN-facial crossing 8.6 mm; crossing to stylomastoid foramen 5.6 mm.
Conclusion:
Temporal bone HRCT delineates an intraosseous ABVN in a clinically meaningful minority of ears and demonstrates reproducible relationships to the chorda tympani and facial canal. A simple, chorda‑tympani-referenced classification may assist in preoperative planning and improve interpretation of auricular vagus stimulation outcomes.
