Paranasal sinuses and the EarKate Dahill and Katie Joyce
Sinuses… Just hollow parts of the skull May get infected, and the infection may spread
What type of cells line the sinuses? Respiratory mucosa - ciliated pseudostratified columnar
epithelium
So, they produce mucus, which drains into…. The nasal cavity
Which sinuses don’t drain with gravity..? Maxillary
SPHENOID sinus drains to SPHENoethmOID recess Others drain to Hiatus semilunaris
Sphenoethmoid recess
Hiatus Semilunaris
Innervation All EXCEPT MAXILLARY innervated by…
CN Va
Which is innervated by.. CN Vb
Pain referral? Frontal head Maxillary – maxillary teeth
Tympanic membraneFlaccid part
Cone of light
Umbo
Tense part
Handle of malleus
3 layers of tympanic membrane:
Skin CN Vc and X
Mesoderm
Respiratory mucosa CN IX (middle ear and auditory tube)
What is in the middle ear? BONES:
Malleus Incus (Inbetween) Stapes (like a stirrup)
Muscles: Tensor tympani – connected to
malleus CN Vc
Stapedius – connected to stapes CN VII
Without muscles -> hyperacusis
Branches of the facial nerve
Pharyngotympanic OR Eustachian OR Auditory tubeWhat does it do?
Equalises pressure between middle ear and throat Drains mucus
When your ears ‘pop’ it’s your eustachian tube opening.
Which pharyngeal arches does the ear derive from?
1 & 2
What is the sensory innervation of the ear? How do you test this?
CN 8 Rinnes and Webers:
Weber;-Tuning fork on forehead and ask where patients hears the sound/vibration and does it lateralise -Normal; no lateralisation -Conduction deafness; sound lateralised to AFFECTED ear-Sensorineural deafness; sounds lateralised to NORMAL ear
Rinne;-Tuning fork on mastoid til sound stops then hold in air by EAM-Air conduction should be better than bone conduction-Conduction deafness; no note at EAM
Rinne Weber
What is the difference between conductive and sensorineural hearing loss?
Conductive loss; sound cant travel to inner ear e.g. outer or middle ear blockage
Sensorineural loss; damage to the hair cells within the cochlea or CN VIII
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