Ear Flashcards
what part of the external ear leads to external auditory meatus
concha
what arteries brach around the external ear and supply the external ear
superficial temporal A. and posterior auricular A.
what is the innervation to the external ear
great auricular N. (most of helix, antihelix, and lobule)
auriculotemporal N. (tragus and canal)
vagus N. (auricular branch) (concha and canal)
facial N. (spots on the concha)
* V FAG to pierce your ear
what nerves innervate the external auditory meatus and external surface of the tympanic membrane (ear drum)
Vagus N. (auricular branch)
Auriculotemporal N. (from V3)
**auriculotemporal does majority of the eardrum
what nerve inneravates the internal surface fo the tympanic membrane
CN 9 (glossopharyngeal)
what is an auricular hematoma
blood between the perichondrium and cartilage of the external ear caused by trauma to ear
*of not drained it can cause cauliflower ear
what are the layers of the external ear
skin–> perichondrium –> cartilage–>perichondrium –> skin
(front to back)
the external auditory meatus extends from the _____ to the ____. the lateral 1/3 is ____ and the medial 2/3 is _____. and a childs meatus is ___ compared to an adults.
- concha to tympanic membrane
- lateral is cartilage
- medial is bone
- childs is shorter (completed by age 9)
how to pull an ear when examining with an otoscope
superiorly, posteriorly, and slightly lateral
what is an external ear infection called? what are the risk factors?
Otitis externa (swimmers ear)
- infection of the external acoustic meatus
- risk factors: excessive moisture, trauma, excessive cleaning, devices that occlude ear canal, dermatologic conditions, previous radiation therapy
what are the divisions of the tympanic membrane? and where is the most vascular site? where is the cone of light?
divisions: anterior superior, anterior inferior, posterior superior, posterior inferior
- most vascular superiorly vs inferiorly
- cone of light is anterior inferior
what boney ear structure is embedded in the tympanic membrane and causes its vibration?
malleus (lateral process)
-handle (or manubrium) with tip at the umbo
where is the pars flaccida? umbo?
- neck of malleus
2. tip of malleus
what protects the epitympanic recess with the 2 heads
the bone around the ear
what is a middle ear infection called ? what can happen as a side effect?
otitis media
- inflammation and swelling of the mucous membrane of the tympanic cavity (cavity in middle ear surrounding the bones of the middle ear) may block the pharyngotympanic tube and cause fluid build up
- fluid can build up and cause pressure and pain
- the tympanic membrane will look red and bulge like
- can rupture eardrum and cause bleeding and temporary conduction deafness
what is a tympanostomy tube placement
-an ear tube place in a pre-made slit of the eardrum in order to drain fluid from the middle ear and allow air in
-can be used to drain fluid as in otitis media
-tubes will remain there and either fall out naturally or removed surgically
(myringotomy is the procedure used to make an incision in the tympanic membrane posterior and inferiorly to avoid blood vessels, chorda tympani, and ossicle bones)
which quadrant of the tympanic membrane does the chorda tympani run
anterior and posterior superior quadrants
T/F
severe otitis media can erode through the boundaries of the middle ear
true
what are the boundaries of the middle ear ?
Roof: tegmental wall (from tegmen tympani bone) separates it from dura mater of middle cranial fossa
Floor: jugular wall (made of bone) separates it from bulb of internal jugular vein
Lateral: membranous wall (made of tympanic membrane separates it from external ear
Medial: labyrinthine wall (made of promontory from cochlea, oval window, round window, and prominence of facial canal) separates it from internal ear
Posterior: mastoid wall (made of aditus to mastoid antrum, and canal for the facial nerve) separates tympanic cavity from mastoid air cells and facial nerve
Anterior: carotid wall (made of opening of eustachian tube and canal for the tensor tympani M. ) separates it from internal carotid A.
if severe chronic otitis media erodes through the floor of the tympanic cavity, what can happen
a clot in the internal jugular vein
what is in the epitympanic cavity
head of malleus and incus
what is the oval window
where the base of the stapes inserts and vibrates to make sound
**“opening where the sound will go through to the inner ear”
what are the contents of the middle ear
- ossicles (malleus, incus, stapes)
- muscles : stapedius and tensor tympani
- chorda tympani nerve
- tympanic plexus
the chorda tympani crosses the medial surface of
the neck of the malleus
