Ear Flashcards
What does the pharyngotympanic tube connect and what is its function?
Connects the middle ear to the nasopharynx. Allows for drainage from the middle ear into the pharynx and helps to equalise pressure (opens during swallowing).
What muscles control movement of the ossicles of the middle ear?
Tempor Tympani
Stapedius
How does the Tempor Tympani control oscillations in the ear?
Attaches to the neck of the malleus and pulls the tympanic membrane medially to reduce the force/ amplitude of vibrations
What nerve supplies the Tempor Tympani muscle?
CN Vc
How does the Stapedius control oscillations in the ear?
Pulls the stapes and limits its range of movement in response to large vibrations
What nerve supplies the Stapedius muscle?
CN VII
What is Hyperacusis?
Heightened sensitivity to certain noises caused by damage to CN VII (causing loss of innervation to the Stapedius muscle of the middle ear)
How can the Chorda Tympani be damaged and what does this result in?
Tympanic Membrane rupture can damage the Chorda Tympani resulting in a loss of taste sensation to the anterior 2/3 of the ipsilateral tongue
Where can middle ear infections spread to and what does this result in?
Mastoid air cells (mastoiditis) Facial nerve (ipsilateral facial palsy) Vestibular system (dizziness)
What is the clinical name for a middle ear infection?
Otitis Media
How does the ear develop embryologically?
From pharyngeal arches 1 and 2
How does the tympanic membrane develop embryologically?
From the ectoderm and endoderm of the 1st pouch and cleft
What is an auricular sinus?
An additional external auditory meatus that develops in front of your pinna (external ear)
Small and non-functional but can become infected or form a cyst
Within which bone is the inner ear located?
Petrous part of the temporal bone (between middle ear and internal acoustic meatus)
What is the nerve innervation to the inner ear?
CN VIII (Vesitbulocochlear) - enters via the IAM and divides into separate vestibular and cochlear branches