Anatomy of the Ear Flashcards
Nerve supply to external auditory canal
might cough if removing wax because vagus nerve supplies afferent cough reflex
What week should ear be formed by?
- what protects tympanic membrane externally
- label
by week 28
Parts of Ear
outer, middle, inner
Arterial supply to pinna
-what vessels
Auricular hematoma:
-what layers does it often form between?
External innervation of pinna
-posterior, anterior, middle
important lymphatic drainage of ear
Outer vs inner parts of auditory canal vs eustachian tube
-bony vs
out 2/3 of eac are soft tissue/ cartilage, inner 1/3rd is bony
eustacian tube: outer 2/3 bone, inner 1/3 soft
- middle ear pressure difference affects what membrane
- external TM innervated by what?
- internal TM innervated by what?
external 5, 7, 10
internal 9
Mesotympanium vs epitympanium
- majority of incus and malleus are in epitympium
- only bone in mesotympium is stapes
adult vs infant ear tubes related to ear infections
infant has less angle, less drainage
parts of the ossicles
-which parts in epitympium
the epitympium portions come from 1st branchial arch
Course of facial nerve through temporal bone
- as it first enters the internal auditory canal
- tympanic segment
- mastoid segment
- facial nerve proper
4 nerves of internal auditory canal
Nerves: 4 nerves of the internal auditory canal
2 of them innervate the vestibule
1 innervates cochlea
1 of them is facial nerve
*Superior vestibular nerve innervates Superior canal, horizontal canal, superior portion of vestibule known as utricle
*Inferior vestibular nerve innervates posterior circular canal, and inferior portion of the vestibule known as the saccule.
*cochlear nerve goes directly to the modulus of the cochlea
*Facial n does the muscle of the stapedius
What are cupulas?
The cupula is located within the ampullae of each of the three semicircular canals. Part of the crista ampullaris, the cupula has embedded within it hair cells that have several stereocilia associated with each kinocilium. The cupula itself is the gelatinous component of the crista ampullaris that extends from the crista to the roof of the ampullae. When the head rotates, the endolymphfilling the semicircular ducts initially lags behind due to inertia. As a result, the cupula is deflected opposite the direction of head movement. As the endolymph pushes the cupula, the stereocilia is bent as well, stimulating the hair cells within the crista ampullaris. After a short time of continual rotation however, the endolymph’s acceleration normalizes with the rate of rotation of the semicircular ducts.
Utricle vs saccule
-motion
utricle is horizontal
saccule is vertical
Frequency perception difference through cochlea
