Functional anatomy and disorders of the ear Flashcards
What is otalgia?
pain in the ear
What is the external ear called?
pinna
contains pinned external auditory meatus and lateral surface of tympanic membrane
What is the ear canal?
external auditory meatus - it is skin lined (keratinising stratified squamous epithelium)
What is the middle ear?
A bony air filled cavity containing ossicles
What is the middle air lined with?
respiratory epithelium
What connects the middle ear to the oropharynx?
the pharyngotympanic tube
What is in the inner ear?
-cochlea and 3 semicircular fluid filled canals
What nerves carry GENERAL sensation from the ear?
- cervical spinal nerves (C2/C3)
- vagus
- trigeminal (auriculotemporal)
- glossopharyngeal (tympanic)
this has implications for referred pain e.g. something wrong with larynx or pharynx can cause ear pain
What nerve carries SPECIAL SENSORY to the ear?
vestibulocohlear nerve (CNVIII) -hearing and baalnce
What should you as a doctor be thinking if a patient comes in with otalgia but has a normal ear examination?
- alternative site of pathology
- otalgia can be non-otological or otological
What are the non-otological causes for otalgia?
- TMJ dysfunction (CNVc)
- Disease of oropharynx (CNIX)
- Disease of larynx and pharynx (cancers)
What is the role of the external ear?
collects, transmits and focuses sound waves onto the tympanic membrane
What conditions can affect the external ear?
- congenital
- inflammatory
- infective
- traumatic
What is ramsey hunt syndrome?
“shingles of the facial nerve)
-bells palsy and a painful red vesicular ear rash
What is perichondritis?
inflammation of the pinna carticlage
-after ear piecings
What is a pinna haematoma?
-the perichondrium is the lining over the cartilage that contains the blood supply to the underlying cartilage so when it is stripped away blood can accumulate between the cartilage and the perichondrium
What is the treatment for pinna haematoma?
Drainage and reaccumulation called re-apposition of the 2 layers
What happens if the pinna haematoma is untreated?
if not treated, can form a cauliflower ear as when ear tries to heal itself, it will lay down scar tissue altering the shape
-common in contact sport injuries e.g. boxing and rugby
When looking in the ear canal, how do you get the best view?
-pull ear back, up and out as the external acoustic meatus has a sigmoid shape
What do you find in the cartilaginous 1/3 of the external acoustic meatus?
hair, sebaceous glands and ceruminous glands (wax) - important as acts as a barrier to foreign objects
bony 2/3 lack these glands and hair
What is otitis externa?
inflammation of the external acoustic meatus - can involve the pinna too
- very painful
- affects hearing as air can’t reach tympanic membrane
can develop into malignant otitis externa - seen in patients who are immunocompromised - infection starts to involve the bone- not just the skin
What causes otitis external?
usually infection but can be allergy e.g. eczema
What are some tympanic membrane common abnormalities?
normal - apex points out to external ear side (only slightly)
buldging - secondary to bacterial acute otitis media (pus built up behind tympanic membrane pushing it more towards to external ear side)
otitis media with effusion - retracted and evidence of fluid within the middle ear cavity - tympanic membrane will be sucked in (due to negative pressure)
What is cholesteatoma?
- rare but should not be missed
- caused by a -ve pressure pull the pockets into the middle ear (due to blockage of the eustachian tube)
- retraction of top part of the tympanic membrane (par flaccid) forming a pocket which traps stratified squamous epithelium and keratin (becomes crusty)
What are the symptoms of cholesteatoma?
- painless
- smell otorrhea (ear discharge)
- can get hearing loss due to retracted tympanic membrane