[Significance of bone changes in the internal auditory meatus in acoustic tumors and in the "empty" enlarged inner ear canal].

The unilateral extension of shortening of the internal auditory meatus is a very safe bony sign of the presence of a neurinoma of the auditory nerve. Differential diagnosis is necessary to exclude an "empty" extended internal auditory meatus. On the other hand, 31% of the definitely established neurinomas do not show up in the plain tomogram. These facts prove that despite the presence or absence of allegedly definite bony changes at the internal auditory meatus further diagnostic measures are imperative, especially an air meatography in conjunction with high resolution computed tomography.