Assessment of sound in the ear canal caused by movement of the jaw relative to the skull.

To assess whether or not the reduction of threshold to bone-conducted sound on occlusion of the ears (the occlusion effect) is due to compression of the auditory meatus by the jaw, measurements of movement of the skull and mandible and sound in the ear canal are reported from four subjects. The change in bone-conducted sound in the ear canal was also measured when the mandible was moved out and in (presenting more or less of the mandible to compress the auditory meatus) and when vibration was applied directly to the mandible. Sound pressure increased when the jaw was moved out and when vibration was applied to the mandible.