External Acoustic Meatus
External Acoustic Meatus Definition
External auditory canal is a passageway leading to the eardrum membrane or tympanic membrane of each ear from the outside of the head.
It is also referred to as:
External Acoustic Meatus Location
The External Acoustic Meatus is located in the temporal bone of the ear. It extends to the tympanic membrane from the opening in the external ear.
External Acoustic Meatus Anatomy
The external auditory meatus structure is similar in every mammal. It appears as a bit curved tubular structure that extend from the auricle floor to inwards or the part of the external ear that protrudes, and blindly ends at the tympanic membrane that isolates it from the middle ear. In the inner two-thirds of the wall of the external acoustic meatus bone is present, while cartilage makes up the outer third part of the canal wall.
The entire external auditory meatus is around 2.5 cm long and tiny hairs and skin lines it. It has a diameter of 0.7 cm, and comprises of bony and cartilaginous sections. The cartilaginous outer third part of the acoustic meatus produces Cerumen, which helps prevent the entry of water, insects, fungi and bacteria into the ear. It is also responsible for the transmission of sound waves. The small hairs project outwards and the ceruminous glands producing earwax or cerumen help prevent the entry of insects into the ear.
External Acoustic Meatus Function
This external ear passageway transports audio waves through the temporal bone and the cartilage to the membranous lateral window of the tympanic cavity or the eardrum (tympanic membrane). The meatus is lined by a glandular integument, with the ceruminous glands or modified sebaceous glands producing the wax for the ear canal.
External Acoustic Meatus Innervation
The External Acoustic Meatus has three nerves supplying to it, which include:
External Acoustic Meatus Pain
Pain in the external auditory meatus can arise due to various reasons:
External Acoustic Meatus Pictures
Check out the following external auditory meatus images and diagrams to get a proper idea about its structures and location.
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