Outer Ear review

Which set of cues help us localize? Pick the best choice.

timing cues, high frequency cues, and intensity difference cues

The three main parts of the ear are

outer ear, middle ear, inner ear

If your external auditory were .04 m long, would its resonant frequency be higher or lower than 3,430 Hz?

Resonant frequency = c/4L

C = speed of sound in air (343 m/s)

L = length of external auditory canal

Lower

Which substance produced by glands in the external ear canal can help protect your ears against insects?

cerumen

The resonant frequency of the pinna is approximately _______________.

1.5 kHz 0r 1500 Hz

This is an image of which condition?

Prearicular Fistula

Based on this image, what do you think the condition might be? Is it a fungal infection, otitis media or perichondritis? 

Perichondritis

what is known as absence of the pinna. Below is an image that shows this congenital condition? 

Anotia

Do you think this is an example of cerumen impaction or a fungal infection? 

cerumen impaction

Which is a possible treatment for this condition? Antibiotics or reconstruction?

antibiotics

This  child appears to have microtia with what other condition? 

Microtia with stenosis, which is narrowing the external auditory canal

The person reports ear pain and small amount drainage coming from their ear canal. They could possibly have which condition of the outer ear? Is it otitis externa, a preauricular fistula, or microtia?

otitis externa

What is the term used when structures of the pinna may be missing and/or the pinna may be smaller than expected? 

microtia 

Do you think this is an example of a fungal infection (otomycosis) or cerumen impaction? 

otomycosis

Audiologists can prescribe ear drops to treat otomycosis. True or False? 

False - the person sees a physician, physician's assistant or nurse practitioner for medical treatment. Audiologists do not provide medical treatment of ear or hearing-related disorders. 

whats this

helix

whats this

antihelix

whats this

Lobule

whats this

triangular fossa

whats this

cymba concha

whats this

crus of helix

whats this

cavum concha

whats this 

antitragus 

characteristics of external auditory canal

curved (s-shaped) and stretches from pinna to tympanic membrane 

first 1/3 is cartilaginous, 2/3 is bone 

about 1 inch long and ¼ in diameter

function of the pinna 

sound enhancement 

you can hear without it but it helps enhance sounds around 1500 hz (resonant frequency) 

gives a boost in high frequencies 

localization 

function of external auditory canal

serve as a resonator with one closed end

resonant frequency for adults is 2700-3400

anotia

absent pinna

cause of anotia

congential; may be associated with a syndrome

treatment of anotia

possible surgical reconstruction; amplification if indicated 

microtia

small pinna, without any landmarks

cause of microtia

also congential; may be associated with a syndrome 

perichondritis

infection of tissue surrounding cartilage

bacterial infection with swelling, redness, and pain

cause of perichondritis

skin conditions

treatment for perichondritis

antibiotics

preauricular fistula (fissue, pit, sinus, cyst)

depression in skin; anterior to helix & superior to tragus 

cause of preauricular fistula

congenital, disruption during development 

treatment of prearicular fistula

antibiotics if infection/ discharge

stenosis

narrowing of the external auditory canal

cause of stenosis

age, or may be congenital

treatment of stenosis

possibly surgery if linked to hearing loss

external otitis

swimmers ear 

possible fever and or drainage for external auditory canal, likely pain, swelling of pinna

cause of otitis

bacterial or fungal infection; humid environment, skin condition, trauma/abraision

treatment of otitis

prescribed ear drops

otomycosis (fungal infection)

itching, possible pain, burning, discharge, hearing loss

cause of otomycosis 

skin conditions, humid environment 

treatment if otomycosis

also prescribed ear drops 

cerumen (ear wax)

can cause a decrease in hearing

possible cause of cerumen impaction

hearing aid use, narrow ear canals, cotton swab use