Term
| Describe the embryological origin of the external ear? |
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Definition
1st and 2nd branchial clefts (mesenchymal cells).
1) First (Hillocks 1-3)
- Tragus
- Helical crus
- Helic
2) Second (Hillocks 4-6)
- Antihelix crus
- Antihelix/Antitragus
- Lobule |
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Term
| Describe the sensory innervation of the Auricle and EAC |
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Definition
1) CN V3: EAC, TM, middle ear
2) CN VII: concha, EAC (Hitselberger)
3) CN IX: Jacobson, tympanic plexus
4) CN X: Arnold, tympanic plexus, antihelix, concha
5) Great auric and lesser occipital contribute |
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Term
| What are the fissures of Santorini and the Foramen of Huschke? |
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Definition
1) Santorini fissures are lymphatic channels in lateral cartilagenous EAC to parotid, glenoid and ITF (extension of infection and malignancy)
2) Foramen of huschke are in bony medial EAC (embryologic defect in inferior tympanic ring) that connects to glenoid, ITF, parotid and route of spread |
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Term
| What is the notch of rivinus? |
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Definition
| Where the pars flaccida attaches directly to squamous temporal bone superiorly (sometimes fibrous anulus is dehiscent in notch) |
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Term
What is the relevance of the following superior temporal bone (floor of middle cranial fossa) landmarks?
1) Arcuate eminence
2) Foramen lacerum
3) Facial hiatus
4) Tympanic canaliculus |
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Definition
1) Approximate SCC location
2) Petrous ICA
3) GSPN
4) Superior part contains lesser SPN, inferior contains Jacobson's nerve (IX) |
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Term
| What are the contents of the vestibular and cochlear aqueducts? |
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Definition
1) Vestibular contains endolymphatic duct and sac, runs from vestibule to posterior surface of petrous pyramid in posterior cranial fossa (opening includes operculum, which overlies enolymphatic sac)
2) Cochlear (periotic) contains perilymphatic duct, which is continuous with subarachnoid space (ends in posterior cranial fossa), inner ear opening is at base of scala tympani |
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Term
| What are the middle ear derivatives from the first branchial arch? Second arch? Otic capsule? |
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Definition
1) Malleus head and neck, incus body and short process
2) Manibrium, long and lenticular process of incus, stapes suprastructure
3) Stapes footplate, annular ligament |
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Term
| What is the cochleaform process versus the pyramidal eminence? |
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Definition
1) Cochleaform process is site of attachment of tensor tympanic muscle tendon (CNV3) to malleus neck/manubrium
2) Site of attachment of stapedial tendon (CN VII) to posterior neck of stapes |
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Term
| What is the most common site of cholesteatoma recidivism and what are the anatomical boundaries? |
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Definition
Sinus tympani (mesotympanum)
Superior (ponticulum)
Inferior (subiculum)
Lateral (facial nerve) |
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Term
| what are the components of the bony vs. membranous labyrinths? |
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Definition
1) Bony (perilymph): vestibule, semicircular canals, cochlea. Cochlear aqueduct and Vestibular aqueduct
2) Membranous (endolymph): enclosed within bony labrynth; Periotic duct (within cochlear), endlyphatic duct (within vestibular) |
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Term
| What is the ductus reuniens? |
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Definition
| Membranous labrynth structure connecting cochlea to saccule (narrowest segment) |
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Term
| What are the functions of the semicircular canals? |
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Definition
Angular acceleration
1) Horizontal (lateral): ampulopetal (toward vestibule) flow increases firing
2) Superior: ampulofugal flow increases firing
3) Posterior: ampulofugal flow increases firing |
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Term
| What are the otolith organs and their function? |
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Definition
Linear acceleration, found within the vestibule. Sensory element of otolist organs is the Macula (similar to Crista ampularis for the SCCs)
1) Utricle (horizontal)
2) Saccule (vertical and gravitational) |
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Term
| What is the innervation of vestibular organs? |
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Definition
1) Vestibular (scarpas) ganglion: contains cell bodies of vestibular nerve
2) SVN innervates HSCC, SCCC, utricle
3) IFN innerves PSCC and saccular |
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Term
| What are the scala tympani, vestibuli and media? What about helicotrema? |
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Definition
1) Scala tympani contains perilymph
- Begins at round window
- Separated from scala media by basilar membrane
2) Scala vestibuli contains perilymph
- Begins at vestibule
- Separated from scala media by reissner's membrane
3) Scala media: contains endolymphand organ of corti (cochlear duct)
4) Helicotrema is an opening between the scala tympanic and the scala vestibuli found at the cochlear apex |
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Term
| Describe the difference in innervation of outer versus inner hair cells. |
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Definition
1) Inner hair cells are single row, rounded shape and each IHC innervated by 10-20 neurons
2) Outer hair cells are 3 rows, 10 OHCs innervated by single neuron |
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Term
What is the hydraulic area advantage of the TM-to-stapes conduction system?
What about the level action of the ossicles?
What is the overall transformer ratio or gain of conduction |
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Definition
1) 17:1
2) 1.3: 1
3) Transformer ratio is 22:1 which is 25-30 dB |
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Term
| What are the SCC functional pairs? |
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Definition
1) Right and left horizontal SCC
2) LARP: Left anterior (superior) + Right Posterior SCC
3) RALP: Right anterior (superior) + Left posterior |
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Term
| What is alexander's law for vestibular function? |
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Definition
If you look in the direction of the fast phase (for pathalogic peripheral nystagmus), the nystagmus will increase.
So for a left sided (cold, hypoactive lesion), fast faze will be opposite (or to the right). So when the patient looks to the right (or away from the lesion), the nystagmus will increase |
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Term
| What is the difference between the SRT and the WRS in speech audiometry? |
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Definition
1) SRT is lowest dB patient can repeat spondee (2 syllable word) 50% of the time
2) WRS is percentage of phonemes repeated after being presented 20-40 dB above SRT. |
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Term
| What is the interaural attenuation for in-era vs. over the ear headphones? |
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Definition
| 70 dB vs. 40 dB (above this you get crossover and need to mask) |
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Term
In what scenarios are the following audiometric findings classically found?
1) 4 kHz notch
2) False depression in bone conduction at 2000 Hz
3) Cookie bite
4) Recruitment
5) Rollover
6) Decreased tone decay |
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Definition
1) Noise exposure
2) otosclerosis
3) Genetic
4) Cochlear hearing loss
5) Retrocochlear (worse WRS with louder sound)
6) Retrocochlear (decreased perception with sustained stimulus) |
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Term
| What is the physiological of the acoustic reflex and how is it impacted pathalogically? |
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Definition
1) cochlea->CNVIII->CNVIII->Trapezoid->bilateral SOC->facial nucleis->CN VII-> stapedius contraction (ipsi>contra)
2) Inability to maintain reflex with sustained sound suggests retrocochlear pathology
3) Loss of reflex seen in otosclerosis (vs. SCCD) |
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Term
| What are transiently evoked OAE compared to distortion product OAE and how are they used? |
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Definition
1) TEOAE: evoked by broadband tone, neonatal hearing screening (presence suggests thresholds of at least 20-40dB)
2) DPOAE: evoked by simultaneous application of 2 pure-tone freq (f1 and f2), with 2f1-f2 resulting in distortion product. Used in hearing screening, ototoxicity, noise-induced hearing disorders. |
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Term
| How is stenger's test for pseudohypacusis performed? |
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Definition
1) 2 tones of same frequency presents to each ear cannot be heard simultaneously if one is louder
2) alleged "poorer" ear actually gets played sounds at higher intensity. If the subject hears nothing, then they are malingering |
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Term
| How is ECOG useful clinically? |
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Definition
1) Increased SP/CAP ratio >0.45 in 66% of meniere's and syphilis
2) Cochlear microfonic generated from OHCs, normal CM suggests normal inner ear function |
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Term
| Which anesthestic agents will impact ABR measurements? |
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Definition
| Phenytoin, ,lidocaine, diazepman, halothane. Not affected by sedation |
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Term
| What are the ABR findings in vestibular schwanomma diagnosis? |
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Definition
1-2 most reliable. Also need MRI
1) Abnormal interaural wave V latency difference (>0.2ms)
2) Abnormal interaural wave I-V and III-V latency difference (good in presence of CHL)
3) Prolonged interwave latency between I-V or III-V
4) Increased absolute latency |
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Term
| What are the non-CI options for Single-sided deafness amplification? |
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Definition
1) CROS: unilateral profound hearing loss
2) BiCROS: Also amplifies sounds on better hearing ear
3) BAHA or bone conduction hearing aid: CHL or mixed HL |
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Term
| Where should the electrode array for a CI be placed? |
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Definition
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Term
| What are the indications for CI? |
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Definition
Adults
1) Bilateral moderate to profound SNHL with minimal HA benefit
2) AzBio (sentence recognition), CNC (word recognition), <50% in ear to be implanted and <60% in best aided condition
Children
1) >9 months
2) Worse than 90 dB HL or <20% WRS if >5 years old
3) SSD if profound in one ear |
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Term
| What are the most common ototoxic medications and how do they act? |
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Definition
1) Aminoglycocides; hair cell injury
- strepto and genta are more vestibular
2) Cisplatin: OHC, stria vascular
3) Furosemide and ethacrynic acid (diuretics)
4) NSAIDS and Salicylates (ASA causes reversible tinnitus |
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Term
| What is the differential for objective tinnitus? |
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Definition
1) Vascular
- IIH, AVM, persistent stapedial artery, paraganglioma, SCCD
2) Patulous Eustachian tube
- Can use estrogen nasal drops or eustachian tuboplasty
3) Tensor/stapedius syndrome
- Avoid stimulant's, reassurance, can section muscle/tendon if resistant |
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Term
| What are the most common causes of otomycosis and how is it treated? |
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Definition
Aspergillus niger (80-90%) followed by Candida (10%).
Debride, acidify, use gentian violet for refractory cases, avoid ear plugs or HA while active |
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Term
| Which children need antibiotics for AOM? |
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Definition
60% of cases resolve in 24h, 80% within 2-3 days (without intervention).
Complicated cases, persistent cases or <6 months need antibiotics |
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Term
| Who is a good candidate for a Bondy modified radical mastoidectomy? |
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Definition
good hearing patient with isolated epitympanic/mastoid cholesteatoma (minimal middle ear disease).
Does not raise tympanomeatal flap or disturb ossicular chain |
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Term
| What are the high risk pathogens for central complications of otitis media? |
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Definition
1) Type III pneumococcus (intracranial predilection)
2) H. influenza B (meningitis)
Route of spread can be direct, hematogenous, lymphatic, through Hyrtl's fissure which is the tympanomeningeal hiatus, an embryologic remnant that connects hypotympanum to SAS. |
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Term
| What does nystagmus induced by pneumatic otoscopy indicate? |
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Definition
| Hennebert sign, can be horizontal canal fistula, perhaps from petrous apicitis |
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Term
| What is Griesinger's sign? |
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Definition
| Edema and pain over mastoid from occlusion of mastoid emissary vein, associated with picket fence spiking fevers in lateral sinus thrombosis. |
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Term
| Which patients often get keratosis obturans? How does it differ from canal cholesteatoma? |
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Definition
1) Young patients with recurrent sinusitis and bronchiectasis
2) Widens the medial EAC but does not erode. KO is often bilateral in young patients, cholesteatoma is unilateral in older patients |
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Term
| What are the treatment options for relapsing polychondritis? |
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Definition
| NSAIDS, steroids for severe attacks, dapsone |
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Term
| How do exostoses and osteoma typically differ? |
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Definition
1) Exostoses: cold water, multiple often bilateral smooth sessile protrusions in medial bony EAC
2) Osteoma: true neoplastic benign growth of EAC, often single, unilateral and at bony-cartilage junction (asymptomatic usually |
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Term
| What are the most common sites of otosclerosis? |
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Definition
1) Fissula ante fenestrum
2) Second most common is round window
60% have +FH, AD with incomplete penetrance, notch at 2KhZ |
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Term
| Patient hears better in noise that in quiet and has red hue behind TM. What is most likely going on? |
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Definition
| Otosclerosis. Paracusis of willis, schwartz sign |
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Term
| What hearing loss is typically significant enough in otosclerosis to warrant stapedectomy? How long do you wait between ears if bilateral? |
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Definition
1) >25dB ABG
2) 6-12 months |
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Term
| What are the genetics of a perilymphatic gusher associated with stapes fixation? What do you do if encountered during stapes surgery? |
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Definition
1) X-linked PL gusher
2) seal opening with graft, place prosthesis, pack and close (consider LD for high-volume or persistent leak) |
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Term
| What vascular anomaly is associated with a persistent stapedial artery? What do you do if you encounter during stapes surgery? |
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Definition
1) Absent middle meningeal artery
2) Either abort or can sometimes do if vessel anterior enough |
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Term
| What gene is associated with slow-growing locally destructive benign tumors of chemoreceptive (neural crest) origin, 1-3% of which are catecholamine secreting? |
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Definition
Paraganglioma (glomus) tumors, DH mutation
10% multiple, <5% malignant transformation, 20% have family history |
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Term
| Which artery supplies jugular paragangliomas in temporal bone? |
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Definition
Ascending pharyngeal. Usually arise from adventitia of jugular bulb.
Appear "salt and pepper" on T2 MRI due to flow voids
Most common symptom is pulsatile tinnitus |
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Term
| What are the glasscock-jackson classes of glomus tympanicum vs jugulare tumors? |
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Definition
1) Tympanicum
- 1 (promontory), 2 (fills ME space), 3 (mastoid), 4 (EAC and anterior to carotid)
2) Jugulare
- 1(bulb, middle ear, mastoid), 2 (under IAC with or without IC extension), 3 (into petrous apex), 4 (clivus, ITF) |
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Term
| What is the Fisch classification of glomus tumors? |
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Definition
1) Middle ear only (tympanicum)
2) Middle ear + mastoid
3) infralabryinthine towards petrous apex
4) <2cm intracranial extension (D1) or >2cm (D2) |
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