Identifying Great Auricular Nerve via Bony Landmarks: A Cadaver Study

Abstract Background The great auricular nerve (GAN) is a sensory nerve supplied by C2–C3 that provides sensation to the angle of the mandible and posterior auricle. It is commonly sacrificed in both elective and nonelective surgeries but does not lead to a significant decrease in quality of life. Purpose This cadaver study aims to assess two bony landmarks, the angle of the mandible (AOM) and the tip of the mastoid process, and calculate a ratio that can reliably serve as a dependable range for identifying the Great Auricular nerve (GAN) during surgical procedures. Study Design Forty-six cadaver sides from the Case Western Reserve University Anatomy Department were dissected to expose the GAN along the AOM, Erb’s point, and mastoid process. This study used two independent observers to calculate the ratio between AOM and mastoid process (mm) divided by the AOM to GAN (mm) along the same angle. Analyses Statistical analyses assessed the reliability of the ratio for identifying the GAN. Mean, standard deviation, and coefficient of variation were calculated, and data normality was confirmed. Interobserver reliability was evaluated using the coefficient of variation. Results The mean ratio was 0.457 with a standard deviation of ± 0.085. The data was normally distributed with a coefficient of variation was 14.21 for the distance between AOM and GAN and 22.00 for the distance between AOM and the mastoid process. Conclusion GAN was reliably found by bisecting about halfway between AOM and mastoid process.