8. Clinical: Middle Ear- Part 2 Flashcards
(12 cards)
What forms the anterior wall of middle ear?
Carotid wall — separates middle ear from internal carotid artery.
What is the length and orientation of the adult Eustachian tube?
~36 mm; 45° angle with horizontal.
What is the most narrow part of the Eustachian tube?
Isthmus — junction of bony and cartilaginous parts.
Which muscle opens the Eustachian tube?
Tensor veli palatini.
What is the function of the Eustachian tube?
Pressure equalization between middle ear and nasopharynx.
What is the role of Ostmann’s pad of fat?
Helps in closing the Eustachian tube.
What is the significance of the cog?
Bony ridge separating supratubal recess and epitympanum; landmark in surgery.
What is Jacobson’s nerve?
Tympanic branch of CN IX — forms tympanic plexus on promontory.
What is the retrotympanum and its significance?
Posterior part of middle ear; important for cholesteatoma clearance.
What is the clinical use of MacEwen’s triangle?
Landmark for drilling mastoid antrum in cortical mastoidectomy.
What is Donaldson’s line?
Line drawn along LSC to identify endolymphatic sac location.
What is Trautmann’s triangle and its importance?
Access point for posterior cranial fossa surgeries.
