Quiz #2- Ears Flashcards
Where does the external auditory canal terminate?
At the tympanic membrane
What separates the external and middle ear?
The tympanic membrane
Where does lymphatic drainage from the external ear flow?
To the parotid, mastoid, and superficial cervical nodes.
Eustachian tube
Connects middle ear with nasopharyngeal and allows passage of air. Normally closed, opens with swallowing or yawning. Allows normalization of pressure on either side of the tympanic membrane so it does not rupture.
Three functions of the middle ear
- Conducts sound from outer ear to inner ear
- Protects the inner ear by reducing the amplitude of loud sounds
- Eustachian tube equalizes pressure on either side of the TM to prevent rupture.
Inner ear
Bony labyrinth, which holds the vestibule, semicircular canals, and the cochlea
Cochlea
Contains the central heating apparatus.
Three levels of hearing function
Peripheral, brainstem, cerebral cortex
Peripheral level of hearing
Vibrations are converted into electrical impulses for analysis by the brain. Electrical impulses are conducted by auditory portion of CN VIII to the brainstem.
Binaural interaction
Capacity of brainstem to locate a sound in space by using information from both ears.
Function of the cerebral cortex in hearing
Identify the sound and begin formulating an appropriate response
Causes of conductive hearing loss
Impacted cerulean, perforated TM, foreign body, pus/blood in middle ear, otosclerosis.
How to treat conductive loss
Increase amplitude of sound
Otosclerosis
Decreased mobility of the ossicles
Causes of sensorineural hearing loss
Pathology of the inner ear, CN VIII, or auditory areas of the cerebral cortex. May occur due to prebycusis, gradual nerve degeneration with aging. Increase in amplitude may not help.
Labyrinth
3 semicircular canals in the inner ear. Provide the brain with information about the body’s position in space. Inflammation can cause vertigo.
Eustachian tube in infants and children
Shorter, wider, and more horizontal. Easier for pathogens from the nasopharynx to migrate to the middle ear causing otitis media.
Risk factors for otitis media in children
- Absence of breastfeeding in first 3 months
- Secondhand smoke exposure
- Daycare attendance
- Male
- Pacifier use
- Season- fall/winter
- Bottle feeding in supine position
Categories of questions for ear subjective assessment (8)
- Earache
- infections
- discharge
- hearing loss
- environmental noise
- tinnitus
- vertigo
- patient-centered care
Otalgia
Ear pain. May be caused by ear disease or referred pain from the teeth or oropharynx.
Otorrhea
Discharge from the ear.
Tinnitus
Phantom sound. May be due to middle ear infections, impacted cerumen, medication side effects, or other ear diseases. Seems louder when no other environmental noise present. May be debilitating.
Infants at risk of hearing deficit
- maternal rubella
- maternal ototoxic drugs
- premature
- low birth weight
- trauma or hypoxia at birth
- congenital liver or kidney disease
Children at risk for hearing deficit
- Meningitis
- mumps
- measles
- otitis media
- illness with persistent high fever
Nationalities with increased OM incidence
Indigenous children from North America, Australia, New Zealand, Northern Europe.
Objective assessment: external ear
- Size and shape
- Skin condition- lesions, frostbite, scaling, crusts, inflammation?
- Tenderness- may indicate infection
- External auditory meatus- swelling, redness, or discharge? Cerumen?
Whispered voice test
Stand 1-2 feet away. Whisper 2 sets of 3 random letters/numbers. Normal score gets at lest 3 right. Test one ear at a time.
Hearing acuity test results in infants and children
Newborn: startle (Moro) reflex and acoustic blink reflex
3-4 months- acoustic blink, stops moving and appears to “listen,” stops sucking, quiets if crying, cries if quiet
6-8 months- infant turns head to localize sound, responds to name
Preschool/school age- screen with audiometer.
