21.8 Anat, ear and auditory tube Flashcards
What is located in the outer, middle and inner ear?
Outer: auricle, EAM (tympanic membrane)
Middle: Space after TM, pertrous part of temporal bone
Inner: sensory receptors
What is the external auditory meatus lined with?
What is the lateral/medial part made of?
Cerumen glands and hairy skin
Lateral 1/3rd: cartilagenous
Medial 2/3rds: bony
What are the anterior/superior walls and external tympanic membrane innervated by?
Where can damage here be referred to?
V3 (auriculotemporal nerve)
TMJ, lower teeth
Where is the TM ‘cone of light’?
Antero-inferior quadrant (light produces a reflection here)
What is the shape of the TM (laterally and medially)?
Lateral: concave
Medially: convex
Where is the epitympanic recess? what does it do?
What is the clinical relevance?
Extends above/after TM. Communicates w/ middle ear via mastoid air cells.
Inflammation can get into mastoid air cells and fester
Which direction does the auditory tube project?
How is this different in children?
Forwards and downwards (easy to drain exudate)
Infants: more horizontal (middle ear infections)
What are the ossicles? What do they look like?
Stapes (stirrup)
Incus
Malleus (lever/handle)
What do the malleus and base of the incus articulate/attach with?
Malleus: attached to TM (& TT)
Stapes: sits over oval window (stapedius)
What is the promentary?
Swelling of the middle ear
What does chorda tympani innervate? What does it travel with?
(VII) sensory innervation to ant. 2/3rds tongue
Travels with lingual nerve
What are the 2 labyrinths? What are they filled with?
Bony labyrinth (perilymph)
Membranous labyrinth (endolymph)
What is the cochlear? What does it contain?
Snail shell structure for hearing
Contains membranous labyrinth (part) and sensors for hearing (duct)
What does the vestibule contain?
Membranous labyrinth (R’ for static equilibrium)
What does the ampulla hold?
Sensory receptors for dynamic equilibrium
