Evaluation of tuberculum auriculare (Darwin's Tubercle) in terms of sexual dimorphism and morphometry

Abstract

PurposeDarwin's tubercle which is known as tuberculum auriculare in Latin nomenclature, is a term used to describe an atavistic thickening on the helix at the junction of the upper or middle thirds. This study aimed to investigate the distribution, morphological characteristics, anatomical localization, and phylogenetic associations of the Darwin's tubercle in a representative Anatolian population sample, with a particular focus on its correlation with sexual dimorphism.MethodsExternal ear anatomy of 300 healthy individuals were examined, type of the auricle and helix were categorized and structure and shape of the Darwin's tubercle were measured. The data were first compared based on sexual dimorphism, and then discussed in the context of its function in other non-human primates and mammals.ResultsNo significant difference was observed in the frequency distribution of auricle types between genders. Across all participants, irrespective of gender or side, oval auricle type was the most prevalent, followed by rectangular type. Among males, helix was most commonly classified as typical in both ears, with the concave type being the second most frequent. Similarly, in females, typical helix type was predominant bilaterally, followed by the wide type.ConclusionThis study found no significant association between Darwin's tubercle and biological sex. Comparative analysis with non-human primates supports this. First time in the literature, quantitative data on the anatomical features and double variations of Darwin's tubercle have been reported. These findings may influence valuable insights for applications in plastic surgery and the design of auricular hearing devices.