Answers:
Fluid lights up on --- and is dark on ---- MRIs.
A) T1; T2 weighted
B) T2; T1 weighted
A patient presents saying they stuck a bobby pin deep in their left ear to "clean it out" when they felt a pop and suddenly had hearing loss on that side. On exam the patient lateralizes weber to the right and demonstrates some nystagmus. What is the most likely diagnosis?
A) Ossicular Discontinuity
B) Stapes subluxation
C) Tympanic Membrane Perforation
D) EAC laceration
E) None of the above
A) T1; T2 weighted
B) T2; T1 weighted
Think "black and white TV = T1 and T2 weighted MRI"
What is the dB difference required for Weber to lateralize?
What is the dB difference required for Rinne to demonstrate BC>AC?
5 dB for Weber to lateralize. 25 dB for Rinne to be negative (i.e. BC>AC).
MC Questions:What is the dB difference required for Rinne to demonstrate BC>AC?
5 dB for Weber to lateralize. 25 dB for Rinne to be negative (i.e. BC>AC).
A patient presents saying they stuck a bobby pin deep in their left ear to "clean it out" when they felt a pop and suddenly had hearing loss on that side. On exam the patient lateralizes weber to the right and demonstrates some nystagmus. What is the most likely diagnosis?
A) Ossicular Discontinuity
B) Stapes subluxation
C) Tympanic Membrane Perforation
D) EAC laceration
E) None of the above
Free Response Question:
What is the maximum hearing loss caused solely by ossicular chain dislocation?
Quick Facts:
Temporal Bone Fractures
-Skull base includes frontal, sphenoid, temporal and occipital bones. Fx of skull base involves 1+ of these.
-20% of skull fx involve Tbone, risk factors = male and under 21.
-Blunt trauma to lateral side of skull often = longitudinal fx.
-Blow to occipital skull may = transverse fx.Pathogenesis
-Longitudinal fx involve squamous portion of Tbone.
-They follow the axis of EAC to middle ear the course ant along geniculate ganglion
and eustachian tube ending near foramen lacerum.
-Otic capsule is spared.
-Transverse fx course directly across petrous pyramid, fx otic capsule, and extend
anteriorly along eustachian tube and geniculate ganglion.
-Longitudinal = 80%, Transverse = 20%
Clinical Findings
-hearing loss, n/v/vertigo.
-Battle sign = postauricular ecchymosis (due to extravasation of blood from
postauricular artery (or mastoid emissary vein).
-”Raccoon” sign = periorbital ecchymosis = associated w/ basilar skull fx involving
middle/anterior cranial fossa.
-May see EAC laceration w/ bony debris
-Usually has hemotympanum.
-May see CSF otorrhea or rhinorrhea.
-Also do tuning for test, weber lateralizes to fx ear if CHl present and contralateral
is snhl present.
-Always document facial nerve function.
What is the maximum hearing loss caused solely by ossicular chain dislocation?
Quick Facts:
Temporal Bone Fractures
-Skull base includes frontal, sphenoid, temporal and occipital bones. Fx of skull base involves 1+ of these.
-20% of skull fx involve Tbone, risk factors = male and under 21.
-Blunt trauma to lateral side of skull often = longitudinal fx.
-Blow to occipital skull may = transverse fx.Pathogenesis
-Longitudinal fx involve squamous portion of Tbone.
-They follow the axis of EAC to middle ear the course ant along geniculate ganglion
and eustachian tube ending near foramen lacerum.
-Otic capsule is spared.
-Transverse fx course directly across petrous pyramid, fx otic capsule, and extend
anteriorly along eustachian tube and geniculate ganglion.
-Longitudinal = 80%, Transverse = 20%
Clinical Findings
-hearing loss, n/v/vertigo.
-Battle sign = postauricular ecchymosis (due to extravasation of blood from
postauricular artery (or mastoid emissary vein).
-”Raccoon” sign = periorbital ecchymosis = associated w/ basilar skull fx involving
middle/anterior cranial fossa.
-May see EAC laceration w/ bony debris
-Usually has hemotympanum.
-May see CSF otorrhea or rhinorrhea.
-Also do tuning for test, weber lateralizes to fx ear if CHl present and contralateral
is snhl present.
-Always document facial nerve function.
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