Dependency relationships among ear characters in a Spanish sample, its forensic interest

The aim of this paper is to provide information on dependency relationships between the morphological characters of the external ear and their importance in physical identification. At present, there is a lack of population data in this field, and little research has been published. Our study sample consisted of 281 Spanish university students of European descent aged between 18 and 31 years old. We analysed a total of 562 ears. For a large number of characters, we found a dependency between anatomically related characters, confirming our hypothesis. For example, we found relationships between ear shape and protrusion, between rolling of the superior and posterior helix, and between the upper and lower parts of the scapha. However, our results also indicated that some anatomically related characters did not present relationships. Thus, we found no dependency between contour shape of the supero-posterior helix and rolling of the posterior helix or between intertragic incisure shape and tragus or antitragus shape. In addition, we found that some characters that are not anatomically related also showed relationships. These included rolling of the superior helix and intertragic incisure shape, and contour shape of the superior helix and the inferior part of the scapha. These results are of great importance and should be taken into account in forensic applications.