Question

Fenestra ovalis is

• A. Air filled cavity of middle ear
• B. External opening of tympanic cavity
• C. Opening of auditory capsule
• D. Communication between pharynx and tympanic cavity

Answer 1

Answer: (C)

Opening of auditory capsule

Fenestra ovalis is also known as oval window. It is the opening or aperture in auditory capsule by which middle ear is separated from the inner ear. It opens into vestibule of inner ear. The base of oval window is occupied by stapes (third ear ossicle). Vibrations induced in the tympanic membrane or ear drum due to sound waves are transferred to oval window through ear ossicles. The oval window then transmits the vibrations to the fluid of cochlea causing movements in basilar membrane. This results in bending of sensory hair cells against tectorial membrane and nerve impulses are generated.

So, the correct answer is 'Opening of auditory capsule'.