Oval window

The oval window (or fenestra vestibuli) is a membrane-covered opening that leads from the middle ear to the vestibule of the inner ear.View of the inner wall of the eardrum (label is fen. oval. — black circle near top)Cochlea The oval window (or fenestra vestibuli) is a membrane-covered opening that leads from the middle ear to the vestibule of the inner ear. Vibrations that contact the tympanic membrane travel through the three ossicles and into the inner ear. The oval window is the intersection of the middle ear with the inner ear and is directly contacted by the stapes; by the time vibrations reach the oval window, they have been amplified over 10 times from what they were when they contacted the tympanic membrane, a testament to the amplifying power of the middle ear. It is a reniform (kidney-shaped) opening leading from the tympanic cavity into the vestibule of the internal ear; its long diameter is horizontal and its convex border is upward. It is occupied by the base of the stapes, the circumference of which is fixed by the annular ligament to the margin of the foramen.