Chapter 13: Special Senses: Ears
stapedectomy
the removal (-ectomy) of the third ossicle, the stapes (staped/o). This procedure is performed to correct otosclerosis
incus
"anvil" anvil; middle of the three auditory ossicles of the middle ear
malleus
"hammer" Auditory ossicle attached to tympanic membrane
stapes
"stirrup" Auditory ossicle attached to oval window.
perilymph
(peri = surrounding; lymph/o = lymph) and filled with endolymph (endo- = within). The bony labyrinth consists of three parts: the vestibule (vestibul/o), semicircular canals, and the cochlea (cochle/o). The first two contribute to the body's sense of equilibrium, or balance. The cochlea houses the organ of Corti, a sensitive receptor with hair cells that relay sound waves to the eighth cranial nerve, or vestibulocochlear nerve. This nerve then conveys impulses to the temporal lobe of the brain. Before long, we'll see that Sara's hearing difficulty may very well be caused by age-related changes of these inner ear structures
cochle/o
cochlea
anacusis
complete deafness
microtia
condition of abnormaly small auricles
semicircular canals
contribute to the body's sense of equilibrium, or balance
vestibule
contribute to the body's sense of equilibrium, or balance
ceruminoma
derived from the glands that produce earwax, which can obstruct the ear canal and detract from a patient's ability to hear
otorrhea
discharge from the ear
ot/o aur/o auricul/o
ear
otalgia
ear pain
tympan/o myring/o
eardrum
cerumen
lubricates the ear and prevents the entry of foreign particles into the internal portions of the ear
macrotia
macrotia (macro- = large; ot/o = ear; -ia = condition), while a condition of abnormally small (micro-) auricles is called microtia
macul/o
macula
tympanoplasty
surgical repair of the tympanum
cochlear implant
surgically implanted to electrically stimulate the cochlea
infectious myringitis
the inflammation occurs in the eardrum (myring/o) and vesicles due to a bacterial or viral infection, it is called infectious myringitis
tympanometry
the process of measuring (-metry) the condition and mobility function of the tympanic membrane or eardrum (tympan/o). A tympanogram is the graph seen as a result of this test
presbycusis
Age-related hearing loss.
auditory brainstem response (ABR)
An electrophysiologic response to sound, consisting of five peaks that represent neural function of auditory pathways. We are most concerned about the timing between 1 and 5. Absence and/or delay in response could represent a problem. (276)
otoscope
An instrument for examining the external canal and tympanic membrane of the ear.
vestibulocochlear nerve
CN VIII Cranial nerve VIII, which runs from the cochlea to the brainstem auditory nuclei
secretory otitis media (OM)
Caused by a myriad of bacteria, acute otitis media is characterized by a sense of fullness in the ear, diminished hearing, pain, and fever. If the inflammation is accompanied by a pus-filled fluid, it is called suppurative OM. If it is characterized, instead, by a clear fluid discharge, it is secretory OM
supporative otitis media (OM)
Caused by a myriad of bacteria, acute otitis media is characterized by a sense of fullness in the ear, diminished hearing, pain, and fever. If the inflammation is accompanied by a pus-filled fluid, it is called suppurative OM. If it is characterized, instead, by a clear fluid discharge, it is secretory OM
organ of Corti
Center part of the cochlea, containing hair cells, canals, and membranes
endolymph
Fluid within the labyrinth of the inner ear
sensorineural hearing loss
Hearing loss caused by damage to the cochlea's receptor cells or to the auditory nerves; also called nerve deafness
conductive hearing loss
Hearing loss or impairment resulting from interference with the transmission of sound waves to the cochlea
oval window
Membrane that covers the opening between the middle ear and inner ear
cerumin/o
cerumen
Meniere disease
The structures responsible for equilibrium and balance are housed in the labyrinth of the inner ear. Meniere disease affects the vestibular labyrinth and can lead to profound hearing loss. The cause of the disease is unknown, but it is marked by vertigo, a sensation that the body is spinning or that objects are spinning around the body. Tinnitus, a subjective noise such as ringing, buzzing, whistling, or clicking—heard in the absence of sound—is another symptom of Meniere disease. Various options exist to treat this disorder, including tranquilizers, antihistamines, diuretics, and surgery to reduce the pressure of the endolymph on cochlear hair cells. It can also spontaneously go away, as Sara's did after two years
eustachian tube
Within the middle ear is the opening for the auditory, or eustachian tube (salping/o). This structure is sometimes identified as the pharyngotympanic tube as well because it joins the nasopharynx (part of the throat) with the middle ear cavity, where the tympanic membrane is. The eustachian tube is lined with a mucous membrane and its job is to equalize air pressure between the middle ear and the external atmosphere
acoustic neuroma vestibular schwannoma
a benign tumor of the auditory nerve that can cause tinnitus and hearing loss
impacted cerumen
a blockage of the external auditory canal with earwax, or cerumen
cholesteatoma
a cystic mass composed of epithelial cells and cholesterol (chol/e = bile; steat/o = fat; -oma = tumor). This can not only occlude the middle ear but also destroy adjacent bones
otologist
a physician who studies and treats diseases of the ear. If nose and throat involvement were also suspected, Sara might have been referred to an ear, nose, and throat (ENT) specialist. But determining which part of the ear is affected is another part of the problem. Dr. Harris has in mind several possible disorders affecting the external, middle, and inner ear. Certain tests will help to narrow these down
tinnitus
a subjective noise such as ringing, buzzing, whistling, or clicking—heard in the absence of sound
tympanotomy myringotomy
a surgical incision (-tomy) of the tympanum to relieve the pressure and build-up of fluid. This procedure may be required for those who don't respond to antibiotic treatment
ruptured tympanic membrane
any type of tear or injury to the eardrum/possibly resulting from pressure, force, or insult from the exterior aspect
tympanic membrane
eardrum (tympan/o, myring/o), marks the division between the external and middle ear. This thick membrane in the middle ear transmits sound vibrations from the external auditory canal through the middle ear and on to the inner ear
hearing aid
electronic devices that amplify sound
salping/o
eustachian tube
audiometric testing
evaluates hearing acuity and helps to establish the degree and severity of hearing loss (audi/o = hearing; -metric = pertaining to measurement). An audiometer is an electric device used to measure the sensitivity of hearing by delivering a series of acoustic tones that range from very low to very high frequencies. The listener signals when the tone is perceived and the results are plotted on a graph called an audiogram. In a variation on this test, pure tone audiometry—measurement of perception of pure tones—is made with all extraneous noises screened out. Still another variation is speech audiometry, measurement of the ability to hear and understand speech
auricle pinna
gathers sound waves and funnels them into the external auditory canal, or meatus. The auricle, a skin-covered cartilaginous flap, projects from the side of the head
otosclerosis
hardening of the innr ear Abnormal bone formation in the osseous labyrinth of the temporal bone causing the footplate of the stapes to become fixed or immobile in the oval window. The result is a conductive hearing loss.
audi/o acous/o
hearing
cochlea
houses the organ of Corti, a sensitive receptor with hair cells that relay sound waves to the eighth cranial nerve, or vestibulocochlear nerve. This nerve then conveys impulses to the temporal lobe of the brain. Before long, we'll see that Sara's hearing difficulty may very well be caused by age-related changes of these inner ear structures
ossicles ossicular chain
include the malleus, incus, and stapes (staped/o), named because they resemble a hammer, anvil, and stirrup, respectively. They are attached to, or articulate with, one another. The "handle" of the malleus is connected to the tympanic membrane. When the eardrum conducts sound to these three ossicles, the ossicles transmit the sound to the oval window through vibration of the stapes. The footplate of the stapes, when it moves, touches this oval window, which leads to the inner ear. Within the middle ear is the opening for the auditory, or eustachian tube (salping/o). This structure is sometimes identified as the pharyngotympanic tube as well because it joins the nasopharynx (part of the throat) with the middle ear cavity, where the tympanic membrane is. The eustachian tube is lined with a mucous membrane and its job is to equalize air pressure between the middle ear and the external atmosphere
labyrinthitis
inflammation of the inner ear (labyrinth/o), may be due to either infection or trauma. Symptoms usually include vertigo, nausea, and nystagmus. Another disorder that can be caused either by trauma or disease is ruptured tympanic membrane, shown in the illustration. This is just what it sounds like—a tear, or perforation, of the eardrum
mastoiditis
inflammation of the mastoid process (mastoid/o) of the temporal bone
otitis media (OM)
inflammation of the middle ear
otitis externa
inflammation of the outer ear
labyrinth/o
inner ear
tympanometer
instrument used to measure middle ear (function)
speech audiometry
measurement of ability to hear and understand speech
auditory canal
meatus
ossicul/o
ossicles
paracusis
partial loss of or impaired hearing
otoplasty
refers to the surgical or plastic repair (-plasty) and/or reconstruction of the external ear
otoacoustic emissions (OAEs)
sounds made by the vibration of the outer hair cells in the organ of Corti; can be measured and used to verify a normal functioning cochlea
staped/o
stapes
macula
structures of the ear involved in maintaining equilibrium are the macula (macul/o) and the semicircular canals, both of which are found in the vestibule. Sensitive hair cells and fluid within these structures can detect changes in the position of the head. Movement of the hair cells generates nerve impulses, which communicate through the brain to the body's muscles and provide for the recovery of balance
tympanostomy myringostomy
the surgical creation of an opening (-stomy) through the eardrum to promote drainage. This procedure also allows the insertion of artificial tubes to maintain this new opening, something often useful in preventing those recurrent ear infections mentioned earlier. In the accompanying photograph, we see the tympanostomy tube in place
mastoidectomy
the surgical removal of the mastoid process
Rinne tuning fork test
the tuning fork is placed alternately near the auditory canal and behind the ear on the mastoid bone to compare how the patient hears sounds transmitted through air (near the auditory canal) with how the patient hears sounds transmitted through bone. This test helps the examiner distinguish between conductive and sensorineural hearing loss. Not being able to hear the tuning fork longer when the sound waves are conducted through the air is a sign of conductive hearing loss. The Weber test is done in conjunction with the Rinne test
Weber tuning fork test
the tuning fork is placed on the midline of the skull to assess bone conduction of sound for evaluation of auditory acuity. It can detect unilateral conductive hearing loss and unilateral sensorineural hearing loss. With normal hearing, the sound the patient hears is the same loudness on each side
pure tone audiometry
used to determine threshold at each test frequency for both ears
Universal Newborn Hearing Screening Test (UNHS)
uses otoacoustic emissions (OAEs) measured by insertion of a probe into the infant's ear canal. Four electrodes are then placed on the baby's head and auditory brainstem response (ABR) is measured while the baby sleeps
vestibul/o
vestibule
