Ear Flashcards
Where can referred pain to the outer ear be from?
Mandible and mandibular teeth CNVc Temporomandibular joint CNVc Laryngopharynx CNX Larynx CNX Cardiac CNX
Which part of the ear does CN VIII supply?
Inner ear
What are the 3 layers of the tympanic membrane?
Skin
Mesoderm
Respiratory mucosa
Which cranial nerve carries pain referral from middle ear to pharynx?
CN IX
What tissue types make up the pinna?
Elastic cartilage
Fleshy lobule
Which part of the external acoustic meatus produces cerumen (earwax)?
Glands in cartilaginous part
What are symptoms of otitis externa?
Pain
Itchy
Why must an adult pinna be pulled postero superiorly during otoscopy?
To straighten the external acoustic meatus in order to view tympanic membrane
Which direction does the cone of light point when viewing a normal tympanic membrane?
Antero inferiorly
Is a normal tympanic membrane concave or convex when viewed by otoscopy?
Concave
What are the 3 names for the tube that connects the middle ear to the nasopharynx?
Auditory tube
Eustachian tube
Pharyngotympanic tube
Name the ossicles of the middle ear
Malleus
Incus
Stapes
Where is the middle ear?
Petrous temporal bone
Which 2 structures do the ossicles connect?
Tympanic membrane
Oval window
What is the role of the ossicles?
Amplify signal from large tympanic membrane to small oval window
What type of joints connect the ossicles?
Synovial
Where does tensor tympani muscle insert?
Neck of malleus
Which cranial nerve supplies tensor tympani muscle?
CNVc
What is the function of tensor tympani?
Reduce amplitude of tympanic membrane oscillations
Which cranial nerve supplies stapedius muscle?
CNVII facial
What is the function of stapedius?
Reduces oscillatory range & excess movement of stapes
What is hyperacusis?
Over sensitivity to certain frequency and volume ranges of sound. Can be result of damage to inner ear or facial nerve palsy
Where is the aditus to the mastoid antrum found in the middle ear?
Posterior / mastoid wall
Which nerve can be damaged by tympanic membrane rupture and what might this cause?
Chorda tympani
Loss of taste on anterior 2/3 of tongue
Middle ear infections can cause dizziness, which structure is affected?
Vestibular system
What is the suprameatal triangle?
Surgical access point for the mastoid/tympanic antrum
What does blockage of the auditory tube cause?
Prevents drainage of middle ear epithelial secretions
Prevents pressure equalisation
Which 3 muscles open auditory tube on swallowing?
Tensor veli palatini
Levator palatini
Salpingopharyngeus
What is the opening of the auditory tube surrounded by?
Tubal tonsil tissue
Which embryological derivatives are involved in formation of the ear?
Pharyngeal arches 1 and 2
1st cleft
1st pouch
What does the 1st pharyngeal arch develop into?
CN V
Tensor tympani
Tensor veli palatini
Malleus and incus
What does the 2nd pharyngeal arch develop into?
CN VII facial
Facial expression muscles
Stapes
Stapedius
Where does the external acoustic meatus develop from?
1st cleft
What does the 1st pouch develop into?
Tympanic cavity
Mastoid antrum
Auditory tube
What is an auricular sinus?
Also known as congenital auricular fistula
Nodule dent or dimple adjacent to external ear
First cleft remnants
What is the difference between suppurative and secretory otitis media?
Suppurative is infection in the middle ear and causes pain and swelling of tympanic membrane
Secretory (glue ear) is mucoid accumulation, can block pharyngotympanic tube and can lead to speech and language development problems in children
How do you determine the difference between conduction and sensorineural deafness?
Conduction - Rinne negative, weber loudest in affected ear
Sensorineural - Rinne positive, weber loudest in unaffected ear
