Lecture 11: The Ear Flashcards
What is exostosis?
When the cartilage of the EAM grows and occludes the EAM resulting in conductive hearing loss.
Describe the path of the EAM?
Slightly angled.
When is comes to the ear, what does pain depend on
Where the infection is because there are several cutaneous nerves involved.
What forms the roof of the middle ear?
“Tegmental wall” formed by:
- Tegmen tympani (part of inner ear)
- Semicircular canal passes through.
What forms the floor of the middle ear?
“jugular wall”
- Jugular vein passes inferiorly
- Tympanic Branch of CN IX passes through this into middle ear onto promontory
What forms the lateral wall of the middle ear?
“Membranous wall”
- Tympanic membrane
What forms the medial wall of the middle ear?
“Labyrinthe wall”
- Promontory (formed from basal coil of cochlea)
- Tympanic plexus (CN 9 branch from floor)
- Oval + Round window
- Lesser petrosal n. (From tympanic plexus)
What forms the anterior wall of the middle ear?
“Carotid wall”
- Pharyngeotympanic tube (eustachian tube)
- Tensor tympanic muscle
- Corda tympani n. (originates from facial n. at risk of trauma because sits behind tympanic membrane)
- Carotidtympanic n.
Write some clinical notes on the eustachian tube:
Cartilage: Well developed to hold patent but in children it is not yet developed well therefore can close easily and cause infections
What forms the posterior wall?
“Mastoid wall”
- Stepedius tendon
- Corda tympani nerve
What are the contents of the middle ear?
Muscles
Ossicles
Corda tympani nerve
Tympanic nerve plexus
