Goes into detail about normal physiological function of the ear, nose and throat. Discussing both the vestibular and cochlear systems of the ear. Also discusses common pathology of the ear and nose, detailing the clinical presentations, investigations and management of these conditions.
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Anatomy
Ear anatomy:
Ear can be divided into 3 parts:
1. Outer ear
2. Middle ear
3. Inner ear
Outer ear:
The external ear can be split into two further
parts:
1. The auricle/pinna
The function of the auricle is to capture and
direct sounds towards the external acoustic
canal
Most of the structures are formed of cartilage
except for the lobule
Important structures: helix, tragus, concha and
lobule
Accumulation of blood between cartilage
and perichondrium (fibrous tissue that
covers cartilage) can disrupt blood supply
to the cartilage. Untreated this can lead to
avascular necrosis resulting in "cauliflower
ear"
2. The external auditory canal
Anatomy 1
, Extends from the concha to the tympanic
membrane
This canal is s-shaped, so pulling back auricle
will straighten this
Outer 1/3 is made from cartilage and produces
wax, inner 2/3 is bone
Tympanic membrane:
Represents the border between external ear
and middle ear.
Tympanic membrane is translucent that allows
visualisation of middle ear structures
Handle of the malleus meets at "umbo",
deepest concavity of the tympanic
membrane
Superior to this point is the lateral process
of the malleus
Pars flaccida is the weakest point of the
tympanic membrane and is flaccid
Light shining from otoscope on tympanic
membrane is called the light reflex:
light reflex at 5 o'clock is a right sided ear
light reflex at 7 o'clock is a left sided ear
(image to the right)
Middle ear:
1. One nerve
Facial nerve runs through middle ear, damage
to this can result in facial paralysis.
Anatomy 2
, 2. Two muscles
Tensor tympani and stapedius attach to
ossicles and restrict their movement when
necessary
This is useful for protecting the ear from
loud noises
Tensor tympani innervated by trigeminal
nerve
Stapedius innervated by facial nerve
(affected in bells palsy)
3. Three bones
Three smallest bones in the body called the
ossicles
Composed of malleus, Incus and Stapes
These bones oscillate when vibrations pass
through tympanic membrane, transfers
vibrations from tympanic membrane → inner
ear
Mastoid process:
This is the area of temporal bone, that contains air cells
that both protects the ear and can equalise ear pressure
These mastoid air cells are sat posterior to the middle
ear ——————————————>
Vulnerable to infection from the middle ear
Eustachian tubes:
Middle ear is full of air however does not have contact
with outside atmosphere due to tympanic membrane
Anatomy 3
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