Session 7 Flashcards
(31 cards)
What are common symptoms of ear disease?
Otalgia (ear pain), discharge, hearing loss (conductive or sensorineural), tinnitus, vertigo, facial palsy
Within which bone of the skull do we find the
the ear?
Petrous part of temporal bone
What are the features of the external ear?
Pinna, external auditory meatus and lateral surface of ear canal
What is the function of the external ear?
Collects, transmits and focuses sound waves onto the tympanic membrane
What are the features of the pinna?
Helix, antihelix, tragus, antitragus, concha, lobule
What is a pinna haematoma and what are the complications?
Accumulation of blood between cartilage and perichondrium. Deprives cartilage of blood supply and leads to pressure necrosis if not drained. Leads to cauliflower ear
Describe the structure of the ear canal
Inner 1/3 is bony, outer 2/3 is cartilaginous. Sigmoidal shape (move pinna up and back to see inside)
What features can you see on a normal tympanic membrane?
Umbo, malleus, incus, pars flaccida (attic), pars tensa, cone of light
What are the features of the middle ear?
Malleus, incus, stapes, oval window, tympanic cavity, epitympanic recess
What is the function of the middle ear?
Contains ossicles which amplify vibration from the tympanic membrane to the cochlea via the oval window
What is the other name for the Eustachian tube?
Pharyngotympanic tube
What is otitis media with effusion (glue ear)?
Build up of fluid and negative pressure in middle ear due to Eustachian tube dysfunction. Not an infection but can predispose to infection. Decreases mobility of TM and ossicles affecting hearing. TM looks retracted and straw coloured. Most resolve spontaneously in 2‐3 months but some may persist adn require grommets
What is otitis media and how does it present?
Acute middle ear infection more common in infants. Otalgia (infants may pull or tug at the ear). Other non‐specific symptoms e.g. temperature. Red +/‐ bulging TM and loss of normal landmarks.
Why do infants have an increased risk of middle ear infections?
Pharyngotympanic tube is shorter and more
horizontal - easier passage for infection from the nasopharynx to the middle ear
What are possible complications of Otitis Media?
Tympanic membrane perforation, facial nerve involvement. Rarer complications include mastoiditis (via mastoid air cells) and intracranial complications (meningitis, sigmoid sinus thrombosis)
Which branch of the facial nerve is particularly prone to damage from pathology in the middle ear?
Chorda tympani - runs through middle ear cavity
What is a cholesteatoma?
A growth usually secondary to chronic/recurring ear infections and blockage of ET. Creates a sucking, negative pressure, drawing eardrum inwards. Can lead to small pocket forming where skin cells get trapped, collect and continue to grow within middle ear. Not malignant but slowly grows and expands, eroding into structures e.g. ossicles, mastoid bone, cochlea
What are the features of the inner ear?
Cochlea and vestibular apparatus
What is the function of the inner ear?
The cochlea converts sound vibration into an electrical signal (action potential) which is perceived as sound. The vestibular apparatus is involved in maintaining our sense of position and balance.
Describe the normal functioning of the cochlea
Movements at the oval window set up movements of the fluid in the cochlea. Waves of fluid cause movement of special sensory cells within the cochlear duct which fire action potentials in CNVIII
Describe the structure and function of the vestibular apparatus
It includes the semicircular canals, the saccule and
utricle: these are a fluid filled series of channels and sacs that respond to position and rotation and maintain our balance
What conditions can result from dysfunction of the vestibular apparatus?
Vertigo, meniere’s disease
What is the apex of the tympanic membrance attached to and what direction does it point?
Malleus - points medially
What is an acoustic neuroma and how does it present?
Rare, slow growing benign tumour arising from the Schwann cells of the vestibular nerve or sometimes the cochlea nerve. The tumour arises on the nerve often within the internal auditory meatus, where, as it grows it will start to compress all nerves running through here.
Typical symptoms of include unilateral hearing loss, tinnitus and problems with
balance.
