Sonographic imaging of the great auricular nerve

The aim of this study is to assess the ability of ultrasound to identify and estimate the normal cross-sectional area (CSA) of the great auricular nerve (GAN) at a defined landmark in healthy adults. The study sample included 80 GANs in 40 participants (11 males, 29 females), mean age 36.5 years, mean height 160.1 cm, mean weight 63 kg, mean body mass index 24.4 kg/m2. Two radiologists separately obtained sonographic images of the bilateral GANs. Each participant was scanned 3 times bilaterally to assess for intraobserver reliability. The mean CSA of the bilateral GANs was 0.8 mm2 (range 0.4-2.7 mm2). The GAN CSA positively correlated with weight, height, and body mass index. This study confirms the ability of ultrasound to reliably assess the GAN at a defined landmark and estimate its normal CSA. Knowledge of how to identify and measure the GAN would be expected to help decrease complications during procedures and help establish normal reference values.