PD - Ear, Nose & Sinus

Sound waves from the air hit the tympanic membrane, which pushes on the ossicles, which then push on the cochlea through the oval window

Briefly describe the pathway sound waves take from the external to internal ear

Membranous labyrinth

Part of the inner ear that is suspended within the bony labyrinth. Series of communicating sacs and ducts. Contains fluid called endolymph

Sensorineural phase

The second phase hearing. Occurs via the cochlea and cochlear nerve

Hearing and equilibrium

What are the two purposes of the ear?

External ear, middle ear and internal ear

What are the three main parts of the ear?

External ear

Part of the ear consisting of the auricle, ear canal and tympanic membrane

Hearing ; balance

Cochlea = _____ and Vestibule = _____

Mastoid process

Which part of the head is the base of the vibrating tuning fork placed on during the Rinne test

Indication of fracture of the middle cranial fossa of the skull, and may suggest underlying brain trauma

A mastoid ecchymosis is an indication of ______

Middle ear

Part of the ear that is air filled and contains 3 ossicles

Inner ear

Part of the ear consisting of the cochlea, utricle, saccule and semicircular canals

External ear and middle ear. NOT the inner ear

What parts of the ear can be seen with an otoscope?

Inner ear

Part of the ear responsible for balance

Auricle

External portion of the ear

Tympanic membrane

Part of the ear that forms the boundary between the external ear and the middle ear

Pinna

What is another name for the auricle?

Helix

The outer ridge of the auricle

Lobule

Inferior, fleshy portion of the auricle

Tragus

Nodular eminence that points back over the enterance to the canal

Helix, antihelix, lobule, tragus, antitragus and concha

What are the 6 components of the auricle?

Concha

The deepest depression of the auricle

The ear is mostly cartilage, which is avascular. Poor blood supply to this area = more prone to infections.

Why should you treat a laceration to the ear more aggressively?

Skin is hairy and contains glands that produce cerumen

Explain the skin of the ear canal

Cerumen

Ear wax is also called ____

Tympanic membrane

What is the lateral border of the middle ear? (*quiz)

Surrounded by bone and lined by thin hairless skin

Explain the skin of the inner portion of the ear canal (close to the tympanic membrane)

The handle of the malleous and the short process of the malleous

What are two chief landmarks of the tympanic membrane?

Umbo (the umbo is a part of the malleous)

Where does the tympanic membrane meet the malleus? (*quiz)

Cone of light

When using an otoscope to examine an eardrum, what should be the first thing you look for to help guide you to see the other structures?

Pars flaccida

Lies above the short process of the malleus. Seen when inspecting the tympanic membrane

Pars tensa

The remainder of the eardrum

Malleus

Which of the 3 ossicles is in close contact with the tympanic membrane?

Much of the middle ear and all of the inner ear CANNOT be seen

What parts of the ear cannot be seen with an otoscope? (*quiz)

Tympanic cavity

Another name for the middle ear

Malleus, incus and stapes

What are the 3 ossicles of the middle ear?

From the tympanic membrane to the fluid filled cochlea

The ossicles articulate with one another to transmit sound waves from the ______ to the ______

Stapes

Ossicle that attaches to the oval window, the entrance to the chochlea (*quiz)

Oval window

Known as the entrance to the cochlea

Eustachian tube

The middle ear is connected to the nasopharynx by the _______

Auditory tube

What is another name for the eustachain tube?

Posterior to the inferior nasal meatus

Where does the eustachian tube open?

When chewing or yawning

The eustachian tubes are usually closed. When do they open?

Equalize the pressure in the middle ear with the atmospheric pressure

What is the function of the eustachian tube?

Levator veli palatini and the tensor veli palatini

What two muscles open the eustachian tube?

Inner ear

Part of the ear located deep within the temporal bone

Bony labyrinth and membranous labyrinth

What are the two components of the inner ear?

Cochlea and vestibular apparatus (utricle, saccule and semicircular canals)

What does the bony labyrinth contain? (*quiz)

Cochlea

Part of the bony labyrinth that is important for hearing

Hearing

What is the main function of the cochlea?

Vestibular apparatus

Part of the bony labyrinth responsible for balance

Utricle, saccule and semicurcular canals

What are the 3 components of the vestibular apparatus?

Balance

What is the function of the vestibular apparatus?

Hearing and euilibrium

What two functions is the bony labyrinth of the inner ear important for?

Endolymph

What is the name of the fluid found inside the membranous labyrinth?

Utricle, saccule and semicircular DUCTS

Membranous labyrinth = ducts

Bony labyrinth = canals

What does the vestibular portion of the membranous labyrinth contain?

Cochlear duct

What does the cochlear portion of the membranous labyrinth consist of?

Oval window

Motion of the stapes against the ______ sets up waves in the fluids of the cochlea, which causes the basilar membrane to vibrate

Sound waves from the outer ear reach the TM, causing vibration of the ossicles. Motion of the stapes against the oval window sets up waves in the fluids of the cochlea which causes the basilar membrane to vibrate. This sstimulates the sensory cells of the Organ of Corti, atop the basilar membrane, sending impulses to the brain

Explain the hearing mechanism from the external ear to the brain

Organ of Corti

Sensory cells that lie on top of the basilar membrane, and send impulses to the brain when stimulated

Scala vestibuli

The upper fluid filled compartment of the cochlea

Scala media

The middle fluid filled compartment of the cochlea

Cochlear duct

What is another name for the scala media?

Endolymph

Fluid within the cochlear duct (scala media)

Scala tympani

The lower fluid filled compartment of the cochlea

Perilymph

What is the name of the fluid found in the scala vestibuli and the scala tympani?

The oval window

The upper scala vestibuli is sealed from the middle ear by the _______ (*quiz)

Round window

The lower scala tympani is sealed from the middle ear by the _____

Helicotrema

Place where fluid from the upper scala vestibuli and the lower scala tympani meet

Thin vestibular membrane

Membrane that covers the ceiling of the chochlear duct and separates it from the scala vestibuli

Basilar membrane

Membrane that forms the floor of the cochlear duct and separates it from the scala tympani

Organ of Corti

The sense organ for hearing (*quiz)

Basilar membrane of the cochlea

Where is the Organ of Corti found? (*quiz)

Superior, posterior and horizontal at right angles to one another (occupying 3 planes of space)

Explain the orientation of the semicircular canals in space

Ampulla

A swelling at the base of each semicircular canal containing hair cells

Semicircular ducts

Lie within semicircular canals

Detect rotational or angular acceleration of the head

What does the orientation of the semicircular canals allow us to do?

Vertigo

Issues with the semicircular canals can cause this condition

At least 1

Acceleration or deceleration during movements of the head in any direction causes movement of the endolymph in __ of the 3 semicircular canals

Cochlea

Converts sound waves to electrical impulses

Cochlear nerve

The electrical impulses of sound waves travel to the brain via _____

Conductive phase and sensorineural phase

What are the 2 phases of hearing?

Conductive phase

The first part of the hearing pathway. From the external ear through the middle ear (*quiz)

Conductive hearing loss

A compaction of cerumen in the ear canal is an example of _____ hearing loss

Cochlea and cochlear nerve

Which two structures are important for sensorineural hearing?

External and middle ear

Which parts of the ear are important for conductive hearing?

Air conduction (AC)

The normal first phase in the hearing pathway

Bone conduction (BC)

Bypasses the external and middle ear. Used for testing (vibrating tuning fork on the skull stimulates the chochlea directly)

Air conduction is more sensitive than bone conduction

In the normal person _____ conduction is more sensitive than ___ conduction

This means that with a tuning fork, you will hear the sound longer than you feel it when it is placed on your head (Rinne test)

Explain what AC > BC means?

Conductive hearing loss

Hearing loss that occurs due to a problem in the external or middle ear

Sensorineural hearing loss

Hearing loss that occurs due to a problem with the inner ear, cochlear or VIII CN

Occupational hx

Taking ____ history is extremely important in patients complaining of hearing loss

Streptomycin and gentamycin

Give 2 examples of prescription drugs that are ototoxic

Aspirin and NSAIDs

Give 2 examples of OTC drugs that can cause hearing loss

Meniere's disease

If tinnitus accompanies hearing loss and vertigo, this suggests ______

Uncontrolled HTN

If a patient is able to hear their heartbeat in their ears, this is indicative of ______

The room is spinning

If a person has "true vertigo", how will they describe it?

Foreign body

Otitis media

TM perforation

Otosclerosis

Cerumen impaction

Give 5 possible causes for conductive hearing loss

Barotrauma

Inner ear infection

Trauma

Tremors

Congenital

Familial

Aging

Give 6 possible causes of sensorineural hearing loss

Weber and Rinne tests

2 hearing tests that help you determine if hearing loss is conductive or sensorineural