Exploring bilateral asymmetry in human ear morphology for forensic identification: a statistical approach

Abstract Background The morphological features of the external ear have been studied and found to be imparting significant uniqueness for the personal identification purpose, including gender and population studies. This study aims to investigate the bilateral variations of the external ear between males and females within the population of southern Uttar Pradesh, India. A total of 150 healthy individuals, consisting of 75 males and 75 females, were chosen for this study. This research prioritized a variety of morphological features of both ears, including auricle length, auricle width, lobule length, lobule width, tragus to antihelix, and anterior crus to notch, subjected to the morphometry for the study of bilateral differences. Initially, the morphometric data was evaluated descriptively. To further examine the deviation, student’s t-test and the Wilcoxon test was employed. Result The external ear morphology showed significant bilateral and sex-based differences. In female samples, the mean auricle length of the left and right ears was found to be 4.361 cm (± 0.49) and 4.397 cm (± 0.323), respectively. In males, the mean auricle lengths for the left and right ears were observed to be 4.36 cm (± 0.45) and 4.619 cm (± 0.422), respectively. Additionally, with the exception of tragus to antihelix distances, male samples showed higher values for auricle width, length and width of lobule, and anterior crus to notch. Auricle length and width of both the ears were found to be significantly different between male and female samples ( p < .001). The male samples showed differences between the two sides, especially in auricle width, lobule length ( p < .001), and tragus to antihelix ( p < 0.05). However, the auricle width and lobule length demonstrated statistically significant bilateral asymmetry in female samples. Conclusion Ultimately, the variation among the same individuals, as well as between males and females was observed that allowed to identify a markedly significant difference between the two groups. Predominantly, males exhibit a considerably higher value than females. The results of this study underscore the insights on bilateral differences in the morphology of external human ear that may significantly contribute in personal identification for anthropology and forensic stand point.