The Ear Flashcards
Describe the aetiology and pathophysiology of “cauliflower ear”
Auricular haematoma
- blood collects between cartilage and pericondrium
- this disrupts the vascular supply to the pinna cartilage
- usually caused by trauma
Describe the anatomy of the tympanic membrane
Cone of light on the anterior part (i.e. 5 o’clock on the right membrane, 7 o’clock on the left)
Pars tensa - opposite the cone of light
Posterior mallear fold
Pars flacida - at the superior part of the membrane
Umbo - in the centre
Name the three auditory ossicles
Malleus - attaches to tympanic membrane
Incus - connects the malleus to the stapes
Stapes - is in contact with the oval window and so transfers vibrations to the inner ear
Which part of the ear contains the auditory ossicles?
Middle ear
Describe the structure and function of the muscles of the middle ear
Tensor tympani - originates from the auditory tube and attaches to the handle of malleus.
Stapedius - attaches to the stapes.
Both muscles contract in response to loud noise to inhibit ossicle vibration, which protects the tympanic membrane.
Describe the innervation of the middle ear muscles
Tensor tympani - innervated by a branch of the mandibular nerve.
Stapedius - innervated by the facial nerve.
Where in the skull is the inner ear located?
Petrous part of the temporal bone
What lies medial to the inner ear?
The internal acoustic meatus
Which nerves provide sensory innervation to the external auditory meatus?
Mandibular nerve (trigeminal) Vagus nerve
Name the two parts of the vestibule
Utricle
Saccule
Which parts of the semicircular canals attach to the vestibule?
Ampulla - wide base of each semicircular canal
What does the membranous labyrinth contain?
Endolymph fluid
What does the bony labyrinth contain?
Perilymph fluid
What separates fluid in the cochlear?
Organ of corti, which includes the basilar membrane
