L16 - Ear, Orbit, and Nasal Cavities Flashcards
1
Q
outer ear: auricle
A
layer of skin over cartilage framework
lobule = fibrous fatty tissue with no cartilage
2
Q
outer ear: sensory innervation
A
- great auricular nerve
- auriculotemporal nerve
- lesser occipital
3
Q
outer ear: external acoustic (auditory) meatus
A
- from auricle to tympanic membrane
- 2.5 cm in length
- S-shaped
- lined by skin and ceruminous glands
4
Q
describe the tympanic membrane
A
- dense fibrous membrane
- covered by skin externally
- covered by mucosa internally
5
Q
describe the tympanic cavity
A
- air-filled cavity within petrous portion of temporal bone
- round window
- oval window
6
Q
describe the round window
A
- enclosed by secondary tympanic membrane: undergoes compensatory excursions with movement of stapes
7
Q
describe the oval window
A
- closed by footplate of stapes
8
Q
what are the 3 auditory ossicles
A
malleus, incus, stapes (attached to oval window)
9
Q
describe the stapedius muscle
A
- inserts onto neck of stapes
- contracts reflexively in response to loud sounds
- ***exam: innvervated by CN 7
10
Q
describe the tensor tympani muscle
A
- inserts onto malleus
- contracts reflexively to loud sounds
- innervated by CN V-3
11
Q
EXAM: what is the CN IX?
A
tympanic nerve
- GSA to mucosa of tympanic cavity, mastoid air cells, and auditory tube
12
Q
describe the lateral petrosal nerve
A
- leaves tympanic cavity to floor of middle cranial fossa
- descends through foramen ovale to infratemporal fossa
- ends in otic ganglion
13
Q
where does the inner ear lie?
A
within petrous part of temporal bone
14
Q
what does the inner ear consist of?
A
- bony labyrinth (lined w periosteum)
- membranous labyrinth
supplied bylabyrinthine artery
15
Q
what is the basilar artery formed by?
A
the fusion of two vertebral arteries
