The External and Middle Ear Flashcards
Innervation of the auricle?
Cutaneous innervation
-greater auricular, lesser occipital and branches of facial and vagus nerves
Why can cleaning your ears sometimes cause you to cough?
Can stimulate the auricular branch of the vagus nerve
Vagus nerve is responsible for the cough reflex.
Vasculature of the auricle?
Posterior auricular, superficial temporal, occipital arteries and veins
What is the external acoustic meatus?
Sigmoid shaped tube extending from the deep part of the concha to the tympanic membrane
What gives the external acoustic meatus structure?
Cartilage from the auricle
Bony support from the temporal bone
Innervation of the external acoustic meatus?
Sensory innervation
-branches of the mandibular and vagus nerve
Describe the direction that the external acoustic meatus travels
Initially superioanterior
Then superioposterior
Then inferioanterior
What are the two layers of the tympanic membrane?
Skin on the outside
Mucous membrane on the inside
Core of connective tissue
What is the tympanic membrane connected to?
Surrounding temporal bone by a fibrocartilaginous ring
How is the malleus attached to the tympanic membrane?
The handle of malleus attaches at the umbro
Continues superiorly and it has a lateral process of malleus at its highest point
What are the parts of the membrane moving away from the tympanic membrane called?
Anterior and posterior malleolar folds
What is an auricular haematoma?
When blood collects between cartilage and overlying perichondrium usually as a exult of trauma
What can an auricular haematoma lead to and how?
Accumulation of blood disrupts the vascular blood supply to the cartilage of the pinna so if not drained quickly, can get a cauliflower ear
What can perforate the tympanic membrane?
Trauma or infection
Otitis media causes pus and fluid to build up causing an increase in pressure so that is eventually ruptures
Membrane normally heals itself, but may require surgery
Function of the auricle?
Captures and transmits sound to the external acoustic meatus
Which bone does the middle ear lie within?
The temporal bone
Where does the middle ear extend from and to?
From the tympanic membrane to the lateral wall of the internal ear
Purpose of the middle ear?
Transmit vibrations from the tympanic membrane to the inner ear via three bones