Anatomy of the Inner Ear Flashcards
What imaging modality is the best for assessing disease in middle ear?
CT
What are the 3 parts of the ear?
External, Middle, Inner
What’s the function of the external ear?
Collects sound waves at the eardrum
What’s the function of the middle ear?
Air filled space where vibrations of tympanic membrane are transmitted by 3 ossicles.
What’s the function of the inner ear?
Membranous filled sac containing receptor cells
What type of slices are required for imaging of the ear? And what 2 planes are used?
Thin
Axial & coronal
The petrous bone is positioned in an _____ orientation from posterolateral to ______
oblique
anteromedial
What direction would structures be sectioned on coronal images?
obliquely
What plane is useful to visualise the length of the ear canal?
Off coronal plane
What 2 structures does the external ear have?
Auricle & External auditory meatus (EAM)
Does the EAM extend inwards or outwards to the tympanic membrane?
Inwards
How long is the EAM and what shape course does it follow?
3.7cm long
S-shaped
The EAM outer lateral portion is ______
Cartilaginous
What 2 types of glands does the overlying skin of the EAM contain? (C__ & S__)
Ceruminous & sebaceous
What does the tympanic membrane do?
Separates middle ear from the EAM
Less than __mm in greatest diameter, the tympanic membrane faces laterally _____ & _____
12
downwards & forwards
What’s the name of the bony spur formed by the lateral wall of the tympanic cavity & superior wall of EAM.
Scutum
Cholesteatoma is formed by the ____ retraction of the pars _____ of the tympanic membrane into the epitympanum
medial
flaccida
What part of the temporal bone is the tympanic cavity/ middle ear located?
Petrous part
Whats the name of the 3 auditory ossicles the tympanic cavity contains?
Malleus, incus, stapes
The lateral wall of the tympanic cavity is formed by the ______ _____ and above this by the ____ part of temporal bone
tympanic membrane
squamous
What is the name of the part of the cavity above the tympanic membrane and what 2 ossicles does it contain?
epitympanic recess/ attic
incus & head of malleus
What is the medial wall of the middle ear?
Round window
The round window is closed by the second tympanic membrane: _____ ______ or ___ window occupied by the base of the _____, the _____ formed by the first part of the cochlea & the prominence caused by the underlying canal for the _____ nerve
fenestra vestibuli oval stapes promontory facial
What structure is attached to the base of the cochlea in the oval window?
Stapes footplate
What are the boundaries of the middle ear?
Lateral
Medial
Superior
Lateral: tympanic membrane
Medial: Round window
Superior: epitympanic recess/ attic
Which is the largest of the 3 ossicles?
Malleus
The malleus has a handle attached to the _____ membrane, a rounded head which articulates with the ___ & a lateral process
tympanic
incus
What 3 parts does the malleus have?
Head, neck & 3 processes