stirrup fixation

stirrup fixation, growth of spongy bone in the wall of the inner ear so that it encroaches on the oval window—an opening in the wall of the bony labyrinth of the inner ear (this bony encroachment is called otosclerosis)—and prevents movement of the stapes, or stirrup, a small bone of the middle ear the base of which rests in the oval window. Normally, sound waves cause vibrations of the eardrum membrane that are transmitted by...