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

Hint: Fenestra ovalis is the oval window which is a connective tissue membrane located at the end of middle ear & beginning of internal ear.

Complete Answer:
- As we know, the air filled cavity of the middle ear is called a tympanic cavity.
- In the case of the external opening of a tympanic cavity we know that this cavity opens into the tympanic tissue.
- In this option there is the opening of an auditory capsule which is called Fenestra ovalis.
- In this option communication in between the pharynx and tympanic cavity and this type of the communication is by the auditory tube.

So, the correct option is C as the right defining of the fenestra ovalis is done in it.

Additional information: The base of the oval window is occupied by stapes (third ear ossicle). Vibrations induced in the tympanic membrane or eardrum due to sound waves are transferred to the oval window through ear ossicles. The oval window then transmits the vibrations to the fluid of cochlea causing movements in the basilar membrane. This results in bending of sensory hair cells against tectorial membranes and nerve impulses are generated.

Note: Fenestra ovalis leads to the tympanic cavity which leads into the vestibule to which the base of the stapes is connected and through which ossicles of the ear transmit sound vibrations. all these works in a regular manner by getting placed one after the other. This helps in order to move the sound from the outside to the inside of the body.