Development of a parametric model of adult human ear geometry

Quantitative knowledge regarding the size and shape of the human ear is valuable for the design of hearing protection and audio devices. In this study, a retrospective analysis of computed tomography (CT) scans from a patient database was conducted in order to address the need for a three-dimensional parametric model of adult ear geometry. A template polygonal mesh was fit to extracted geometry of the pinna, canal, and adjacent scalp for 331 ears from 224 men and women aged 18–81 years. Principal component analysis demonstrated a large amount of variance in the position and orientation of the ears with respect to the skull. A regression analysis confirmed previous findings of sex differences in the increase of ear size with increasing age and demonstrated an effect of body mass index on ear position and orientation that has not been previously described.