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Mapping ear canal movement using area-based surface matching
Malcolm J Grenness1, Jon Osborn, W Lee Weller
1Discipline of Anatomy and Physiology, University of Tasmania, Australia. grenness@tassie.net.au
The Journal of the Acoustical Society of America
|February 28, 2002
Summary
The external ear canal moves significantly relative to the concha during jaw motion. This study quanties the three-dimensional movement of the ear canal, revealing considerable variability between individuals.
Area of Science:
- Anatomy
- Biomechanics
- Otology
Background:
- Jaw motion influences the external ear canal's position.
- Previous research suggested ear canals primarily widen with jaw opening.
Purpose of the Study:
- To quantify the three-dimensional movement of the external ear canal relative to the concha during jaw motion.
- To assess the variability in ear canal deformation between open-jaw and closed-jaw positions.
Main Methods:
- Collected paired open-jaw and closed-jaw ear impressions from 10 subjects (14 ears).
- Utilized a reflex microscope to obtain 3D coordinate data of the concha and anterior ear canal surface.
- Employed area-based matching software to analyze surface distortion and map canal movement (anterior-posterior, superior-inferior, medial-lateral) relative to the concha.
Main Results:
- The concha region showed minimal deformation.
- Ear canals exhibited significant, variable deformation, with root-mean-square (RMS) values up to 136 micrometers.
- Medial-lateral movement ranged from +2.0 to -3.8 mm.
- Superior-inferior movement ranged from +3.7 to -2.7 mm.
- Anterior-posterior movement ranged from +7.5 to -8.5 mm.
Conclusions:
- The external ear canal demonstrates substantial and variable three-dimensional movement relative to the concha during jaw motion.
- Findings contradict previous reports suggesting only widening occurs with jaw opening.
- Highlights the complex biomechanics of the ear canal and its interaction with jaw movement.