Midterm Flashcards
What is the outer ear composed of?
Pinna
Ear Canal
Ear Drum
What is the outer ear responsible for?
Gathering sounds from the environment and funneling them down into the ear canal
Another word for Pinna
The Auricle
What is the pinna made of?
Made entirely of cartilage
The concha
Aids in localization of sounds that come from in front, behind, below and above the head
Anatomy of the pinna
Makes it more efficient at delivering high-frequency sounds than low-frequency sounds
The EAC (External Auditory Canal)
also known as external auditory meatus
elliptical shape tubed that begins at the concha and extends down to the tympanic membrane
What is the Tympanic Membrane also known as?
The eardrum
What is the greatest surface area of the Tympanic Membrane called?
Pars Tensa
Pars Flaccida
Also knowsn as shrapnells membrane is looser and contains only the epidermal and mucous membrane layers
What is the tympanic membrane held in place by?
Annulus
Umbo
the point where the bottom end of the manubrium forms the center of the eardrum
What does a healthy normal eardrum look like?
cone shaped and will produce a visible phenomenon or light reflex (cone of light)
Cone of light
anterior inferior quadrant
3 layers of the tympanic membrane
Ectoderm: cutaneous, continuous of the external auditory canal
Endoderm: mucous, continuous with the tympanic cavity
Mesoderm: fibrous, radial fibers, concentric fibers
Disorders of the Auricle
Microtia: congenital deformity where the pinna is underdeveloped
Antonia: congenital in nature , pinna is entirely absent
Dysfunctions of the External Auditory Canal
Stenosis
Collapsing ear canals
Hematoma
Cerumen Impaction
Foreign Bodies
Atresia
Absence of the external auditory canal
Unilateral is more common than bilateral
Growths in the External Auditory Canal
Osteoma: Bony Tumor
Exostoses: outward projections for the surfaces of bone
External Otitis
An infection that occurs in the skin of the external auditory canal
Develops in people who have water trapped in their ears
Middle Ear
Carries vibrations from the outer ear to the inner ear by transferring the sound energy from the air in the outer ear to the fluids in the inner ear
Epitympanic Recess
Space in the middle ear above the tympanic membrane
Middle Ear Cleft
Eustachian Tube and Middle ear
Lined with mucous membrane
Endoterm
Middle ear space and Eustachian tube form from the pharyngeal arch which is lined with endoterm
Dilated epithelium lines these spaces
Ossicles
First form as cartilage of the first and second pharyngeal arch
Begin to differentiate by the 12th fetal week, fully formed by the 16th week and total ossification if the malleus take place by week 21
Middle Ear Space
Lateral wall (membranous wall) encompasses the tympanic membrane
The roof is a thin layer of bone
Below the floor is the jugular bulb
Behind the anterior wall is the cartoid artery’s
The inner ear lies behind the media, wall
The mastoid process lies behind the posterior wall
The Ossicular Chain
Vibrations from the tympanic membrane set the ossicular chain into vibration
Contains:
Malleus (Mallet/Hammer): the manubrium is embedded in the middle,e layer of the tympanic membrane
Incus (anvil): the short crus attached to the posterior ligament of the incus, the long crus articulates with the stapes at the lenticular process
Stapes (stirrup): base forms a footplate which sits on the oval window
Middle ear system
Serves the important functions of matching the low impedance of the air in the external ear canal to the high impedance of the fluid within the inner ear
30dB would be lost
What is the Eustachian tube also known as?
Auditory tube or pharyngotympanic tube
Eustachian tube
Connects the middle ear space to the nasopharynx and is ciliated and lined with mucous
1/3 bone 2/3 cartilage
Opening and Closing of the Eustachian Tube
Legatos Veli Palatini & Salpingopharyngeus
Tnesor tympani & Tensor Veli Palatini
Windows of the middle ear
Cochlear promontory: portion of the inner ear which protrudes in the middle space
Oval Window: Membrane covered opening that indicates the end of the middle ear and beginning of the inner ear
Round Window: sealed by the secondary tympanic membrane which vibrates with opposite phase to vibrations entering the inner ear through the oval window
Mastoid Process (Bony Protuberance)
back part of the temporal bone
attaches to various muscles and has openings for the transmission of blood vessels
filled with mastoid cells
Non Auditory Structures (Middle Ear)
Facial Nerve
Chorda Tympani Nerve
Stapedius Muscle
Tensor Tympani Muscle
Disorders of the Middle Ear
Negative Middle Ear Pressure: Poor function of the eustachian tube
Facial Palsy: weakness of the facial muscles
Patulous Eustachian Tube: chronically open eustachian tube
What is the inner ear made up of?
semicircular canals and the cochlea
What is the function of the inner ear?
transduce the mechanical energy delivered from the middle of the ear into a form of energy that can be interpreted by the brain
reports information regarding the body position and movement in space to the brain
Bony Labyrinth
rigid bony outer wall in the temporal bone
consists of:
vestibule, semicircular canals and cochlea
Membranous Labyrinth
collection of fluid filled tubes and chambers which contain the receptors for the senses of equilibrium and hearing
lodged within the bony labyrinth
consists of:
utricle and saccule
Vestibular Mechanism
the vestibular system sends signals primarily to the neural structures that control eye movements
contributes to out sense of balance and spatial orientation
What 2 components are the vestibular components composed of?
Semicircular canals: rotational movements
superior X
Posterior Y
Horizontal/Lateral Z
Otoliths: linear accelerations
Saccule
Utricle
Cochlea
part of the inner ear involved in hearing
spiral shaped cavity which is made up of the bony and membranous labyrinth
organ of the corti
the sensory organ of hearing which is distributed along the partition separating the fluid chambers in the cochlea and runs from the bottom to the top
Scala Vestibuli: lies superior to the cochlear duct and connects with the oval window
Scala Tympani: lies inferior to the cochlear duct and terminates at the round window
Scala Media: a region of high potassium ion concentration that the stereocilia of the hair cells project into
Reissners membrane
separates the scala vestibuli from the scala media
Basilar Membrane
main structural element that separates the sala media from the scala tympani and determines the mechanical wave propagation properties of the cochlear partition
Cochlear Tonotpy
Higher frequencies cause movement in the base of the cochlea and lower frequencies work at the apex
Outer Hair Cells
primarily innervated by efferents, originating from neuronal cells found in the brain stem
responsible for the sharpening of the traveling wave and further enhance frequency discrimination
Inner Hair Cell
innervated by approximately 95% of the spiral ganglion cells
transduce basilar membrane vibration into electrical activity
Audiological Evaluation
aid in the process of making decisions regarding:
the type of hearing loss present
the extent of the hearing loss
developing a plan
Audiogram
a graph that shows the softest sounds a person can hear at different pitches or frequencies
the closer the marks to the top of the graph, the softer the sounds that person can hear
normal hearing
-10 to 15 dB
slight hearing loss
16 - 25 dB
mild hearing loss
26 - 40 dB
moderate hearing loss
41 - 55 dB
moderate severe hearing loss
56 - 70 dB
severe hearing loss
71 - 90 dB
profound hearing loss
higher than 90
Normal Hearing (Audiometric presentation)
bone conduction and air conduction match and are within the normal range of hearing
little to no air bone gap is present
Cause of Conductive Hearing Loss
Fluid in the middle ear from colds, allergies, poor ET, ear infection
impacted earwax
infection in the ear canal
Conductive HL (Audiometric)
usually involves a reduction in sound level
bone conduction is normal and air conduction is depressed due to the reduced amplitude of sound energy
Sensorineural HL (Audiometric)
Occurs when hair cells, neural fibers or their connections to the cochlea are damaged
Bone conduction matches air conduction and is usually present as a sloping hearing loss
Causes for Sensorineural HL
Aging
Noise exposure
Genetic conditions
Congenital and birth related hearing loss
Drugs and medication
Causes for mixed HL
A mixed loss is the type of hearing loss associated with a mixture of a conductive and sensorineural hearing loss
Mixed HL (Audiometric)
Used only when both conductive and sensorineural hearing losses are present
Bone conduction and air conduction are both depressed and a difference exists between the two
Vestibular Ocular reflex
Required for clear vision
and enables us to maintain our desired position in space
Stabilizes images on the retina during head movement
Length
Frequency increases as length of the vibrating portion of the string is shortened
Frequency decreases as the vibrating portion of the string is lengthened
Mass
The mass of an object also affects the frequency of vibrations. Thicker guitar strings produce lower-frequency vibrations, whereas thinner guitar strings produce higher frequency vibrations
Stiffness
The frequency of vibrations increases directly as stiffness of the object is increased and Vice versa.
If tension is decreased, vibration frequency decreases.
Otoscopy
To identify abnormalities which may require alternate Audiometric procedures or influence the results obtained
To identify conditions which may require medics, referral
Air Condition
Conducted using headphones or speakers
Ear specific information can be obtained with headphones
Bone Conduction
Signals are delivered directly to the cochlea, bypassing the outer and middle ear and delivered via bone oscillator
The bone oscillater is placed on the mastoid behind the test ear
Responses are recorded by the site in which the bone oscillator is placed
Bone conduction must be obtained to determine the type of HL
Tuning Forks
When the skull is set into vibration as by a bone conduction vibrator or a tuning fork, the bones of the skull become distorted resulting in the distortion of:
-the structures of hearing within the cochlea of the inner ear (distortions, bone conduction)
-this distortion can also set the stapes
Tuning Fork Tests
Rinne Test
Weber Test
Audiometric Weber
Acute Otitis Media
Acute Otitis Media: an infection of rapid onset that usually presents with ear pain
Signs include building of the tympanic membrane
Treat by wait and see
Otitis Media w/Effusion
also known as serious otitis media
A collection of usually non infected fluid accumulation that can occur in the middle ear and mastoid air cells due to negative pressure produced by dysfunction of the Eustachian tube
Treatment: wait and see, possibly ademoidectomy
Chronic Suppurative Otitis Media
Chronic inflammation causing mucosal edema, ulceration and perforation of the middle ear and mastoid cavity
Discharge
Antibiotics
Complications of Middle Ear Surgery
- Cause hearing loss
What is the inner ear also known as?
Labyrinth
Afferent System
Traveling upwards towards the brain
Ipsilateral
Contralateral
Audiometric Testing Booth
Booths are not soundproof but rather sound proofed or sound treated
The room is designed to minimize reverberation
Test Booth
vary in size
windows to see and communicate with the patient
doors with acoustic seal
Position of the Patient
Patient should not be able to oversee the audiologist so as to obtain any cue
Patient should still remain observable by the audiologist
Why is HIPPA needed?
Health Insurance Portability and Accountability Act
HIPPA was created primarily to modernize the flow of health care information
Adult Case History
General:
What brings you in?
Medical
Other
Pediatric Case Study
Utero health and birthing process
Development and Milestones
Overall Health
Parent Observations
Observations by others
Non organic HL (Malingering)
Patients who claim to have hearing loss but actually have normal hearing or lesser degree hearing loss than is being presented
Objective Tests for Malingers
Auditory Evoked Potentials: The auditory pathway is stimulated under headphones and responses are recorded, evaluated, and interpreted by the audiologist
Otoacoustic Emissions: can serve as a screener for person suspected of falsifying their results
Threshold Measurement Procedures
Present the tone
If they do not respond, increase the intensity
When a positive responses is obtained from the examiner, drop 10 dB, if they can’t hear it raise 5 dB
Count this response towards the threshold
Hughson Westlake Method of obtaining threshold
THRESHOLD IS DEFINED AS THE
LOWEST INTENSITY AT WHICH
THE TONE HAS BEEN HEARD BY
THE PATIENT AT LEAST 50% OF
THE TIME FOLLOWING A MINIMUM
OF THREE ASCENDING
PRESENTATIONS AT THAT LEVEL
(E.G., AT LEAST 2 OUT OF 3, 2
Speech Detection Threshold (SDT)/Speech Awareness Threshold (SAT)
Lowest level at which a patient can barely detect the presence of speech and identify it as speech
Useful when a patient cannot engage in other speech measuring tasks
Speech Recognition Threshold (SRT)
Lowest hearing level at which speech can be understood
Uses 2 syllable words
Speech Recognition Score
Estimating the communicative ability of the individual at normal conversational level
