Session 7 - functional anatomy and disorders of the ear Flashcards
what is otalgia
ear pain. pain that originates within the ear is primary otalgia; pain that originates outside the ear is referred otalgia.
Typical sources of primary otalgia are external otitis, otitis media, mastoiditis, and auricular infections
wihtin which bone of the skull do we find parts of the ear
petrous part of the temporal bone
what parts make up the external ear
what is its function
pinna
external auditory meatus
lateral surface of tympanic membrane
collects, transmits, and focuses sound waves onto the tympanic membrane
how does cauliflower ear occur
secondary to blunt injury to the pinns
accumulation of blood between cartilage and perichondrium
deprives the cartilage of its blood supply + pressure necrosis of
tissue
Prompt drainage of blood, measures to prevent re-accumulation and re-apposition of two layers are necessary
Untreated or poorly treated leads to fibrosis and new
asymmetrical cartilage development- ‘cauliflower
deformity’ of the ear
why can ear infection affect the facial nerve and cause facial palsy
the facial nerve travels through the internal auditory meatus
what is ramsey-hunt sydrome
is a herpes zoster oticus
where you get unilateral facial palsy
caused by the reactivation of the varicella zoster virus from the geniculate nucleus (nucleus if the facial nerve)
in what way does the ear have to be positioned to examine it
straighten it by pulling it back and up as it has a sigmoid shape
where are the gland that produce wax and hair found
outer part of ear canal (cartilaginous)
how long is the external acoustic meatus
2.5cm
what is ottitis externa
Inflammation of the external acoustic meatus usually caused by infection, sometimes due to allergy or irritation
Give ear drops/ steroids if infection
Swimmers ear- lots of water in ear predispose to this
More commonly seen in people with eczema
how do you get a perforated tympanic membrane
Pressure has built up on the inside
Which can cause the tympanic membrane to perforate
Pus and exudate can leak out
Usually resolves itself
can also be due to poking the ear with things
why might you get bulging of the tympanic membrane secondary to ottitis media
bulging due to increased pressure with the build up of immune cells
what is the middle ear
and which bones are found here
tympanic cavity - the air filled cavity between the tympanic membrane and the inner ear
three ossicles- incus, malleus and stapes
what do the ossicles do
Connected via synovial joints and relay vibrations from the tympanic membrane to the oval window of the cochlea (inner ear)
Transmitting vibration from an air medium to a fluid-medium
what protects the ear from very loud noises
Movement is ‘tampered’ by two muscles tensor tympani and stapedius (faical nerve)
Muscles contract automatically if potentially excessive vibration due to loudnoise (protective; acoustic reflex)
what is otosclerosis
Ossicles can become fused at articulations, in particular between base plate of stapes and oval window (otosclerosis)
Sound vibrations cannot be transmitted
Causes deafness
Patients develop gradual hearing loss
why might you get hyperacusis
Can get hyperacoustis if they have facial nerve damage- lose ability to dampen loud noise
as the stapedius muscle which contracts when there is loud noise is innervated by the facial nerve
why do we get a negative pressure in the middle ear
Mucous membrane of middle ear continuously reabsorbs air in middle ear causing negative pressure
what is the function of the eustachian tube
Pharyngotympanic tube (Eustachian Tube) allows equilibration of pressure within middle ear cavity with that of the atmosphere. It also allows for ventilation of and drainage of mucus from the middle ear
what is glue ear
otitis media with effusion
not an infection
Build up of fluid and negative pressure in middle ear due to Eustachian tube dysfunction: can predispose to infection
Decreases mobility of TM and ossicles- affecting hearing
Most resolve spontaneously in 2-3 months.. but some may persist
if glue ear persists what has to be done
Require grommets (tympanostomy tube) to ventilate middle ear and equilibrate pressure
why do we get the formation of a transudate in glue ear
cannot equilibrirate pressure in middle ear
negative pressure draws fluid out of mucosa
how does the tympanic membrane look in glue ear
retracted and straw coloured
because of the negative pressure pulling the membrane towards the middle ear cavity
can also see a build up of fluid behind membrane giving straw colour
what is acute otitis media
Acute middle ear infection
More common in infants, Otalgia (infants may pull or tug at the ear)
non-specific symptoms e.g. temperature
Red +/- bulging TM and loss of normal landmarks