Question | Answer |
From slide one label 1-7 | 1. Crura(antihelix)2. triangular fossa 3. Cymba 4. anterior notch 5. external auditory meatus 6. cavum 7. tragus |
From slide one (the pinna) label 8-14 | 8. intertraqual notch 9. lobule 10.antitraqus 11.antihelix 12.Antihelical fold 13. Scaphoid Fossa 14. helix |
What is the cavum and the cymba parts of? | The concha of the pinna |
What happens to (the embryo)that is important for the inner and the middle ear at 3 weeks? | The inner ear has somites develop
the middle ear has the tubo tympanic recess begin |
What happens to the embryo at 4 weeks that is important to the inner ear? | otic cyst and the branchial arches and grooves start to develope |
What happens to the embryo at 5 weeks that is important for the outer ear? | The external canal begins to form |
What happens to the embryo in the 6th week that is important to
Inner ear
Outer ear | Inner- vestibular organs form
Outer- 6 hillocks appear 3 on the mandible and 3 on the hyiod - these become the pinna |
What happens to the embryo at 7 weeks that is important to the inner ear? | 1st coil of the cochlea |
What important happens to the fetus at 8 weeks that is important to
the middle ear
the outer ear | Middle- lower half of tympanic cavity is formed by extended tubotympanic recess
Migrating cells from 1st arch reach tympanic cavity and form incus and malleus
Outer- Lateral cartilaginous 1/3 of canal is formed |
What happens to the fetus at the 9th week that is important to the middle ear? | The 3 layers of tympanic membrane form
the layers are mucus membrane, connective tissue, and skin |
What happens to the fetus in the 11th week that is important to the inner ear? | Cochlea lengthens to 35 mm and is 2 5/8 turns
the VIII cranial nerve (hearing nerve) attaches to cochlea |
what happens to the fetus in the 12th week that is important in the inner ear? | sensory cells appear in cochlea
otic capsule begin to ossify |
What happens in the 20th week that is important to the
inner ear
outer ear | inner ear- sensory and supporting cells formed inner ear hearing is functional
outer- pinna completes |
What happens in the 21st week that is important to the middle ear? | meatal plug disintegrates showing tympanic membrane |
What happens in the 32nd week that is important to the middle ear? | malleus and incus complete ossification |
what happens to the fetus in week 34 that is important to the middle ear? | mastoid air cells develop connected to the middle ear |
what happens around 2 years of age the is in relation to the development of the ear? | The TM becomes vertical |
What is a zygote | a fertilized egg- 24 hrs till 72 hrs |
What does the blasto-pore become? | anus |
What week does the branchial arches and grooves show? how many are there | week 4 and 5 |
Which branchial arches are important to the ear? what do they become | The 1st arch becomes 2 bones in the middle ear
the 2nd arch becomes part of larynx |
what are the 4 devisions of the temporal bone? | Squamas, mastoid, tympanic, and petrous |
What are the 4 articulations of the temporal bone? | occipital, parietal, sphenoid, and zygomatic |
Where is the squamas located? | It is the flat area above the ear ( thin and hard) |
Where is the mastoid located? | It is behind and below the ear canal. |
Where is the tympanic division of the Temporal bone located? | front wall, floor and back wall of ear canal. It is the inner 2/3 of the ear canal |
Where is the petrous located? | It can not be seen from outside. It is on the ridge between the middle and posterior fossa |
at what angle is the pinna extended from the head | 30 degrees |
what can surgeons use the ear lobe for? | bandages- is good fat to bandage wounds with |
what is cerumen? | Ear wax |
where is the ear canal the widest?
The narrowest? | Widest- junction of cartilage and bone
Narrowest at TM |
The ear canal is how long and has what shape? | 2.5mm and is in a lazy s shape |
What are the 4 contributions of the outer ear? | 1. sound location (aka pinna focusing)but this is freq specific. you gain 3 dB of sound from 3000-6000 Hz 2. Resonance 3. localization 4. protection of the middle ear |
How many inches are ear separated by? what does this help with? | 8 inches and it helps localization |
The middle ear- what is its volume? | 2cc |
what is on the lateral surface of the middle ear? | The TM (tympanic membrane) |
What are features of the TM? | 1. umbo 2. Pars flaccida 3. Pars Tensa 4. Cone of light |
What is on the superior surface of the middle ear? | Tegman Tympani |
What is the inferior surface of the middle ear? | Separates the tympanum from the jugular fossa. |
What possible tumor could erode the tympanum floor? what are symptoms? | Glomus Jugulare
symptoms are to hear woosh sounds and that it is blue behind the TM |
What does the anterior wall of the middle ear do? What is on the anterior wall? | Separates the tympanum from the carotid canal.
The musculo- tubal canal is in the lower part of the wall- for opening the eustachian tubes |
What are the features of the Posterior wall of the middle ear? | the stapedius muscle(smallest we have) and the Aditus- the opening to the antrum of the mastoid |
What are the features of the medial wall of the middle ear? | The oval window- 3.2 sq mm
the round window- 2.3 sq mm
canal for the VII nerve (facial nerve)
Promontory- bony accommodation for the lateral semicircular canal and base of cochlea |
what are the parts of the ossicular chain? | malleus
incus
Stapes |
what are the features of the malleus? | 1. head 2. neck 3. manubrium 4. anterior proces |
what are the features of the incus? | 1. articulating facet 2. long process 3. lenticular process (right angle) 4. posterior process |
what are he features of the stapes? | 1. head 2. neck 3. crura -anterior and posterior 4. footplate |
What type of joint does the malleus and incus have? | ball and socket |
What type of joint does the incus and stapes have? | hinged |
what muscles attach to the ossicular chain | tensor tympani- to the neck of the manubrium
25 mm tendon pulls malleus anteriorly and medially
Stapedial muscle- to the neck of the stapes
6mm pulls posteriorly |
eustachian tube goes from where to where? | The carotid wall aka anterior inferior to the musculo- tubal canal goes to the naso-pharynx |
How long is the eustachian tube? | Adult 35- 36mm is at a 45 degree angle
Infant 17-18 mm |
What lines everything in the middle ear? | Mucosa or mucus membrane |
what are the names of the hairs in the Eustachian tube? | cilia |
what are the 4 major sections of the eustachian tube? | Osseous- from carotid wall for 16mm
Isthmus- about 1mm where bone meets cartilage
Cartilaginous- 12-25 mm long
Membranous- 4 -5 mm long ends at toros tubarius in nasopharynx |
what 2 muscles open the eustachian tube? | tensor veli palatini- primary
Levator vili palatini- secondary |
What is the gain of the areal ratio function in the middle ear? | 27dB |
The areal ratio is a result of? | the difference in surface area of the pars tensa 55 mm^2 and the oval window 2.3 mm ^2 |
What is the spot of the superior surface of the middle ear called that accommodates the malleus? | Epitympanic recess |
The development of the pinna stats with- | 6 hillocks- 3 on the hyoid arch and 3 on the madibular arch in the 6th week |
The arcuate eminence is in which temporal division | Petrous |