Jaw movement and bone-conduction in normal listeners and a unilateral hemi-mandibulectomee.

Relative movement between the mandible and skull may compress the auditory meatus and produce an excess sound in the ear canal. To test this, measurements of sound pressure in the ear canal, and movement of the upper and lower jaw are reported on normal subjects and a unilateral hemi-mandibulectomee. On the side the unilateral hemi-mandibulectomee has a jaw and in the subjects with normal jaws, the data confirm that mandible-movement relative to the skull produces sound in the ear canal. The excess sound in the ear canal when the jaw is free to move independently of the skull can be predicted from the relative movement between them.