Measuring and comparing normal ear protrusion using computerized tomography

The normal external ears of 128 Japanese individuals (64 men and 64 women) were measured using the angle-measuring function of analytic software for computerized tomography (CT). The initial baseline for measurement was the orbitomeatal line (OM line); second measurements were taken 1 cm above the baseline (OM+1 cm), and third measurements 2 cm above the baseline (OM+2 cm). The sample was divided into two groups by sex (64 men and 64 women) and into three groups by age (20-39, 40-59, and 60+), and protrusion measurements for the three sections were compared by both sex and age. The results showed that males have larger auricular values (auricular concha cranial angle, auricular concha scaphoid angle, auricular cranial angle) than do females. In terms of age, the results showed that the auricular concha cranial angle becomes larger with increasing age, while the auricular concha scaphoid angle and auricular cranial angle become smaller with age. (author)