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23 Cards in this Set
- Front
- Back
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Mastoid Process
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- contain mastoid cells that have snot and air
- very close to sigmoid sinus, internal carotid artery and internal jugular vein - continuous with the internal ear |
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External ear
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- made up of elastic cartilage (except lobe just fat)
- external auditory canal- cartilage and skin and bone that form external auditory tube |
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cerumen glands
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- modified sweat glands that produce ear wax
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blood supply external ear
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- posterior auricular artery and anterior auricular branches off the superficial temporal artery
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Sensory
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1. Facial- posterior and behind the ear
2. vagus and glossopharyngeal in middle 3. auriculotemporal- front and upper 4. Cervical plexus (greater auricular and lesser occipital) - does inferior |
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Middle Ear
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- starts at tympanic membrane
- continuous with pharynx via the auditory/pharyngotympanic tube - mostly cartilage but some bone |
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Bones of the middle ear
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- malleus, incus, stapes
- all synovial joints |
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Muscles
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- Tensor Tympani- pulls on malleus and tenses ear drum
* innervated by V3 - stapedius pulls on stapes- tenses ear drum to dampen loud noises * innervated by facial |
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inner ear
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- found next to the internal acoustic meatus
- has cochlea for hearing and semicircular canals for balance in the x,y, and z directions |
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how hearing is transduced
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1. Stapes rocks on the oval window which produces movement in the cochlea
*endolymph in the bony labyrinth and perilymph in the membranous 2. Pressure released by the round window |
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Cochlea
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- goes up modiolus
- point where it turns back on itself called helicotrema - inside is scala vestibule (superiorly) and scala tympani (inferiorly) - scala tympani contains the basilar membrane |
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fluid movment
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- up scala vestibule
- down helicatrema - into scala tympani *here wiggles hair cells |
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innervation to inner ear
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- semicircular canals innervated by vestibular part of vestibularcochlear (CN VII)
- cochlea innervated by cochlear part CNVIII |
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entry of bacteria through auditory tube
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- could lead to infection of mastoid air cells
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what attaches to center of tympanic membrane
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- handle of the malleus
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where does the tympanic nerve/plexus lie
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- medial wall of the ear
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roof tympanic cavity
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- thin part of temporal bone called tegmen tympani
- separates tympanic cavity from dura |
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floor
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- jugular wall
- separates tympanic cavity from internal jugular vein |
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lateral wall
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- membrounous
- superior is epitympanic recess |
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medial wall
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- seperates tympanic cavity from internal ear
- oval and round windows |
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carotid wall
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- anterior wall
- seperates tympanic cavity from carotid canal - superiorly has opening for auditory tube and canal for tensor tympani |
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posterior wall
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- has opening in superior part to mastoid antrum
- connects tympanic cavity to mastoid cells - canal for the facial nerve descends between posterior wall |
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function of the pharygotympanic tube
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- equalize pressure in the middle ear with atmospheric pressure
- tube must be actively opened **done be levator peli vallintini and tensor veli palatine ** why yawning pops ears |
