Session 7 Flashcards
Structures in the external ear?
What lines the canal?
Role?
Pinna
External auditory meatus
Skin
Transmits and focuses sound waves to tympanic membrane
Structures in the middle ear?
Type of cavity?
What lines the cavity?
What tube connects it with oropharynx?
Ossicles
Air filled cavity
Respiratory epithelium
Pharyngotympanic tube (eustachian)
Structures in the internal ear?
Type of cavity?
Cochlea
Semicircular canals
Fluid filled
Non-ontological causes of ontalgia?
TMJ dysfunction-CN Vc
Disease of oropharnyx- CNIX
Facial palsy and red ear?
Cartilage infection?
Ramsey-Hunt syndrome, varicella zoster of facial nerve
Perichondritis
What’s a Pinna haemotoma?
Problem?
Treat?
If left untreated?
Accumulation of blood between cartilage and overlying perichondrium. From blunt injury to Pinna. Subperichondrial haemotoma.
Deprived cartilage of blood and nutrients causing necrosis.
Drainage and re-apposition of two layers.
Fibrosis causing cauliflower ears.
What is the external acoustic meatus lined with?
What’s the canal continuous with?
Makeup?
What does the cartilaginous part consist of?
Keratinised stratified epithelium.
Tympanic membrane.
1/3 is cartilaginous the rest is bony.
Sebaceous glands and hair to protect from foreign objects. And ceruminous glands producing ear wax.
How does the external acoustic meatus clean itself?
Describe otitis externa?
Complication?
Desquamation then epithelium migrates out laterally of tympanic membrane and out of the canal.
Swelling and inflammation of the external acoustic meatus. Caused by exma or pseudomonas aeruginosa.
Malignant otitis externa, in immunocompromised patients where infection inlvolves bone as well.
What does a bulging tympanic membrane suggest?
Evidence of fluid/bubbles and retraction of tympanic membrane?
Acute otitis media
Glue ear/ otitis media with effusion
Describe a cholesteatoma
Symptoms?
Complication?
Retraction of Pars Flaccida (top of tympanic membrane) causing crusting due to increase negative pressures in the Eustachian tube (chronic dysfunction of tube usually). The retraction traps stratified squamous and keratin which can proliferate and erode through all structures.
Smelly otorrhea and hearing loss but painless.
Can erode bone such as mastoid process and ossicles.
Role of ossicles?
Roles of tensor tampani and stapedius?
Amplify and relay vibrations from the tympanic membrane to the oval window of the Cochlea. Transmits vibration to waves in fluid medium.
contracting if noise is too loud to protect.
What is otosclerosis?
Ossicles fused at articulations due to abnormal bone growth usually between base plate of stapes and oval window. So sound vibrations not effectively transmitted to cochlea so conductive loss of hearing in young adults.
Role of phrayngotympanic tube? (Eustachian)
Equilibrates pressure of middle ear with atmospheric pressure. Also allows ventilation and drainage of mucus from middle ear intomoropharynx.
Describe otitis media with effusion (glue ear)?
Treat?
Can predispose infection due to stagnation of fluid,usually from Eustachian dysfunction. The build up of fluid and negative pressure in the middle ear descreases mobility of TM and ossicles affecting hearing.
Usually resolved in 2/3 months. But if effecting speech then grommets which are tubes to maintain equilibrium pressures.
Describe acute otitis media?
Symptoms?
Cause?
Middle ear infection
Otalgia,temperature
Usually viral but can be strep.p or Haemophillis influenza
Why is otitis media more common in infants?
Complications of otitis media?
A shorter pharyngotympanic tube so easier route for viruses and tube can block more easily.
Perforation of tympanic membrane ( fluid after severe pain).
Facial nerve palsy as close to middle ear via facial canal. Two branches run to chorda tympani and stapedius.
Mastoiditis
How can mastoiditis occur from otitis media?
Role of inner ear structures?
Middle ear cavity communicates via mastoid antrum via mastoid air cells. Providing route for infection to spread to mastoid bone (air cells).
Hearing position sense and balance
How does the cochlea work?
…. Vestibular apparatus?
Both are?
How does inner ear disease present?
It converts fluid movement (generated by foot of stapes) into AP’s in CN VIII to be perceived as sound.
Converts fluid movement (generated by position of head) into AP’s in CN VIII to be perceived as position sense and balance.
Fluid filled tubes
Hearing loss, Tinnitus, Vertigo
Role of the oval window?
It’s movements set up movements of fluid in the cochlea duct which move special sensory hair cells in cochlea (stereocilia) which generate AP’s in CN VIII which are sensed by the primary auditory cortex to allow hearing.
What does the vestibular apparatus consist of?
How they work?
Semicircular ducts, saccule, utricle all fluid filled tubes containing stereocilia.
Fluid movement sensed by stereocilia which generate AP’s in CNVIII which is perceived and Maintains our balance.
Presbycusis?
Benign paroxysmal positional vertigo??
Sensorineural hearing loss with old age (bilateral)
Vertigo. Short lived from movement of head. Caused by dislodged crystals moving fluid.
Ménière’s disease?
Acute labrynthitis?
Acute vestibular neuronitis?
Vertigo,hearing loss and tinnitus. Usually unilateral. Too much endolymph. 30 min to 24 hour episodes.
All inner ear structures, hearing loss, tinnitus, vomiting and vertigo.
No hearing disturbances or tinnitus just acute onset of vomiting and vertigo lasting days.
How is the nasal cavity lined?
Two bones making up external nose?
What lines the vestibule of the nose?
Olfactory mucous membranes with olfactory receptor neurones for smell. And respiratory mucous membrane with pseudostratified columnar ciliated (filters) rich in goblet cells. Rich blood supply (warmth).
Nasal bone and frontal process of maxilla.
Skin containing sebaceous/sweat glands. And hair to filter expired air.
Posterior communication of nasal cavity?
Why is the lateral wall irregular?
Role of conchae?
Nasopharynx
Due to bony projection (conchae):
Superior-part of ethmoid
Middle-part of ethmoid, meatus filters most things
Inferior-meatus connected with orbit via nasal lacrimal duct.
Slows airflow with turbulence allowing warming and humidyfying.
Role of openings in lateral wall of nasal cavity?
Describe septal haemotoma formation?
Complication?
Para nasal sinuses can drain into nasal cavity and connection with orbit.
Cartilage supplied by overlying perichondrium. Nose injury can buckle septum and shear BV’s. B accumulates subperichondrium depriving the cartilage.
If untreated then avascular necrosis of septum forming saddle nose deformity.
What CN carries general sensation to nasal cavity?
Oropharynx?
Trigeminal (V2)
Glossopharyngeal
What are nasal polyps?
Symptoms?
Fleshy,benign swelling of mucosa membrane. Bilateral.
Watery Rhinnorhea, decreased smell.
What is rhinitis?
Symptoms?
Causes?
Inflammation of nasal mucosal lining.
Nasal blockage, rhinorrhea, post nasal drip, sneezing
Acute infective or allergic
Name for nose bleed?
Arterially supply to nasal cavity?
Most common place of nose bleed? Where arteries anastomose.
Venous drainage?
Why is sphenopalatine artery more serious if epistaxis?
Epistaxis
Ophthalmic and maxillary artery
Anterior septum (kiesselbachs)
Pterygoid venous plexus
Harder to tamponade
What are paranasal sinuses?
Lined with?
Role?
Where do they drain?
Sensory innervation of sinuses?
Air filled spaces that are extensions of nasal cavity.
Respiratory mucosa (thus ciliated and goblets)
Humidity and warm inspired air and lower weight of skull.
Nasal cavity, via Ostia into a meatus normally middle.
CN V frontal,ethmoid,sphenoid=Va Maxillary=Vb
What is acute sinusitis?
Often secondary to?
Diagnosis?
Treatment?
Inflammation of mucosal lining and paranasal air sinuses.
Viral infection of nasal cavity.
Blocked nose,rhinnorrhea, pyrexia,headache
Antipyretic,steam
Pathology of acute sinusitis?
Infection leads to reduced cilia function and oedema of nasal mucosa and sinus Ostia. General increase in secretions. So drainage of sinus is impeded, most commonly maxillary sinus.
Stagnant secretions are ideal breeding ground for secondary bacterial infection.
