Ear and Auditory Tube Flashcards
What makes up the outer ear?
the auricle and the external auditory meatus
What is the function of the auricle of the ear?
collecting and localising sound
What is the nerve supply for the sensory innervation of the external auditory meatus?
posteroinferior side innervated by vagus and anterosuperior side innervate by the auriculotemporal nerve (a branch of the manibular division of the trigeminal nerve)
Where is the cone of light on the tympanic membrane and why is it an important clinical sign?
the cone of light should be in the antero-inferior quadrant - if it is in another place it indicates too much pressure in the middle ear
What are the two spaces in the middle ear?
tympanic cavity proper an the epitympanic recess
How would an infection get into the mastoid process of the temporal bone?
the epitympanic recess communicates with the air spaces in the mastoid process
How do you equalise pressure in the middle ear?
via the auditory tube which connects the middle ear to the nasopharynx
Why are children more prone to middle ear infections?
their auditory tube is more horizontal than in adults
What are the three ossicles?
malleus, incus, stapes
How are the ossicles connected?
synovial joints
What are the two muscles in the middle ear, what is their function and what nerves are they innervated by?
tensor tympani (innervate by the trigeminal nerve) and stapedius (innervated by the facial nerve) - function to dampen sound
Which nerve travels through the middle ear?
chorda tympani - a branch of the facial nerve that goes to the tongue
What nerve runs above the middle ear?
facial nerve
What artery travels below the middle ear?
internal carotid
Where is the inner ear?
in the petrous part of the temporal bone
