Two procedures were used with one subject to examine changes in the ear canal with jaw motion. Siliconeear impressions were examined to measure the effect of jaw position. Magnetic resonance imagingwas used to define the three-dimensional structure of the canal and visualize key underlying tissue.Results showed that inexpensive impressions can detail changes in the cartilaginous region of thecanal. Approximately a 25% change in this subject's ear canal with different jaw positions was observedin the anterior/posterior plane with essentially no change in the superior/inferior plane. This is likely related toasymmetric stress from action of the mandibular condyle on neighboring cartilaginous tissue. Solutions tojaw motion-induced feedback problems are suggested.