Evaluation of the External Ear and Head Anthropometric Dimensions Among Fars and Turk Workers for the Ergonomic Design of the Earmuffs

Background: Anthropometry plays an important role in the ergonomic design of hearing protection equipment and its compatibility with the dimensions of the external ear and head of workers. Few studies have been conducted on the dimensions of the external ears and heads of workers in Iran with different ethnicities. Objectives: This study aimed to collect the anthropometric dimensions of the external ear and head of workers of two prominent ethnicities of Iran for the ergonomic design of earmuffs. Methods: Following a cross-sectional design, this study was performed on 300 male workers (150 Turk and 150 Fars) aged 20 - 60 years. Anthropometric dimensions of the external ear and head were measured using a spreading caliper, camera, tripod, and tape measure. Photographs were analyzed using Digimizer V5.3.5 software, and data were analyzed using SPSS 21. Results: The mean age of Turk and Fars workers was 33.51 ± 5.41 and 33.95 ± 6.05 years, respectively. The ear shape was oval in more than half of the male workers of the two studied ethnicities. There was a positive correlation between anthropometric dimensions of head and ears in both ethnicities. The 95th percentile of the length and width of the pinna in Fars and Turk workers was larger than the average dimensions of inner ring earmuffs. Conclusions: Hearing protection devices available in the Iranian market should be examined to fit the ear dimensions of different Iranian ethnicities. External ear anthropometric data obtained from this study can be used to redesign the earmuffs in Fars and Turk male workers.