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36 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What does the external ear consist of?
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- Auricle/Pinna
- Auditory canal |
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How is the auditory canal divided?
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Outer 1/3rd - surrounded by cartilage, hairy skin, cerumen glands
Inner 2/3rds - surrounded by bone, hairless/glandless skin, sensitive to skin |
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Difference between adult and child auditory canals.
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Adult - curved, pointing inward, forward, and upward
Child - points forward but not upward. |
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What cranial nerves innervate the ear? Importance?
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- V, VII, IX, X
- Pain can be referred from teeth, tonsils, pharynx, cervical lymph nodes, and larynx |
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What is external otitis?
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- an infection of the external auditory canal
- develops due to maceration of skin in the ear canal (ex. swimming) or trauma to the ear canal |
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Signs and symptoms of external otitis.
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pain, erythema, swelling of ear canal, tenderness with pressure over tragus or with traction on the pinna
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What is malignant external otits?
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-life-threatening; usually in diabetics
- Pseudomonas aeruginosa - osteomylitis of temporal bone can occur |
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What are exostoses?
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- bony growths beneath the skin of the inner ear canal
- due to repetitive exposure to cold water - prevention via alcohol swabs or keeping ear dry |
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What makes up the middle ear?
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- Eustachian tube
- ossicular chain - mastoid system - separated from external ear by Tympanic Membrane |
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What is the tympanic membrane's function?
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- transducer, converting sound waves to mechanical energy; amplifies sound 20x
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How do you visualize the TM?
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- pull pinna up and back
- use largest speculum that comfortably fits - advance speculum down and forward |
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Normal landmarks behind TM?
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- umbo or end of malleus
- handle of malleus - short process of malleus - incus |
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What is visible w/ otoscopy?
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- pars tensa - major portion visible
- pars flaccida - most superior aspect - normall = pearly coloration - cone of light shines anteriorly and inferiorly |
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Role of eustachian tube?
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- Connects nasopharynx to middle ear space
- Normally closed but opens w/ swallowing |
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What does pneumatic otoscopy/tympanogram test for?
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- tympanic membrane mobility via air puffs
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What makes up the inner ear?
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- cochlea, internal auditory canal, semicircular canal in petrous portion of temporal bone
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What makes up the auditory system?
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- cochlea and cochlear portion of 8th nerve
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What makes up the vestibular system?
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- semicircular canals (rotational motion), utricle and saccule (linear acceleration and gravitational force), and vestibular section of 8th nerve
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Why use cold/warm water irrigation?
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- both assess vestibular function
- normal = nystagmus - COWS - cold opposite, warm same |
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Pathways of hearing
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-tympanic memberane, ossicles, oval window, scala vestibuli, hair cells of organ of Corti, electric potential to auditory cortex
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Sensorineral pathway = Organ of Corti - auditory cortex
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Cause of conductive hearing loss
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- interruption in transmission of sound from auditory canal to oval window
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Difference between adult and child conductive hearing loss.
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Child - most common = middle ear effusion 2ndary to eustachian tube disfunction
Adult - most common = otosclerosis - fixation of stapes to oval window Other causes = perforated ear drum, cerumen impaction, foreign body, otits externa/media |
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What is sensorineural hearing loss?
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- problem with inner ear, 8th cranial nerve, or CNS
- caused by exposure to loud noise, Meniere's disease, 8th nerve injury b/c of infections/ medications, and aging (presbycusis) |
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What does a midline Weber w/ AC>BC Rinne bilaterally mean?
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Normal hearing
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What does a lateralized Weber with BC>AC in affected ear and AC>BC in normal ear Rinne mean?
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Conductive hearing loss
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Whad does a lateralized Weber with a AC>BC in both ears Rinne mean?
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Sensorineural hearing loss
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What is suppurative (purulent) otits media?
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- acute infection of middle ear lining
- bacterial or viral infections - usually due to eustachian tube dysfunction during URT infection - due to vacuum space in fluid accumulation = bacterial growth = S. pneumoniae and H. influenzae and viral infections - second most common reason for doctor's visit in small children |
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Symptoms of purulent otitis medai?
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- mild-mod pain
- conductive hearing loss - fever - red and outward-bulging TM - pain not intensified with pain or pressure on external ear - TM may rupture due to pressure = no more pain, TM will heal - complications if untreated = hearing loss, meningitis, and mastoiditis |
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What is serous otitis media?
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- fluid in the ear without infection
- usually in children and infants - due to smaller, horizontal eustachian tubes - same as purulent without bacteria or virus - contributing factors - allergic inflammation and overgrown adenoid tissue |
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Signs of serous otitis media?
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- lack of pain
- straw- colored fluid behind TM - conductive hearing loss - if occuring in adult without history of URT infection = evaluation for nasopharyngeal carcinoma |
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What is a cholesteatoma?
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- skin growth in middle ear due to repeated infection
- causes ingrowth of skin of tympanic membrane - forms pouch, releases enzymes = destroys middle ear = dizziness, muscle weakness = deafness, brain abscess, meningitis, and death |
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What is vertigo?
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- 2nd most common after hearing loss
- sensation of movement usually rotatory or spinning - make sure to distinguish btwn light-headedness and vertigo |
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What is central vertigo?
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- 20% of cases
- due to lesions in brainstem or cerebellum - PDX = cranial neuropathies or dysarthria or ataxia - purely horizontal or vertical nystagmus w/ no tortional component - does not change with position and not inhibited by visual fixation |
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What is peripheral vertigo?
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- 80% of cases
- usually horizontal w/ tortional component - directed away from affected side - suppressed by visual fixation |
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3 common causes of peripheral vertigo?
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- Acute labyrinthitis - assoc. w/ antecedent viral infection; vertigo severe for few days then resolves in weeks; assoc. w/ nausea and vomiting
- Benign positional vertigo - due to calcium debris in post. semicircular canal; one minute or less; recurs for several weeks provoked by specific head movements -Meniere's disease = triad = hearing loss, vertigo, and tinnitus- due to over-production or under0absorption of endolymphatic fluid |
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What is tinnitus?
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- sensation of sound in absence of acoustic stimulus
- objective tinnitus - when examiner hears it too - caused by tonic muscle contraction of pharyngeal or inner ear muscles and vascular conditions (ex. arterial bruits, AV fistuals, venous hums) - subjective tinnitus - when only the pt hears it - due to loud noise, cerumen impaction, otosclerosis, otitis meda, eustachian tube dysfunction, systemic diseases (DM, hypertension), retrocochlear pathology (acoustic neuromas or MS), and ototoxic medications (ASPRIN, aminoglycoside antibiotics) |
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