Ear anatomy Flashcards
What is the function of the auricle?
Collect, focus, and direct sound down the funnel-shaped external acoustic meatus to the tympanic membrane
What antibodies have been identified in cerumen?
IgA, IgG and IgM
What is the predominant immunoglobulin in normal and inflamed ears?
IgG for both
What is the function of the Eustachian (auditory) tube?
Equalize pressure on both sides of the tympanic membrane
Name the 2 structures that attach to the malleus
Tympanic membrane and incus
Name the 3 components of the middle ear
Tympanic cavity, 3 auditory ossicles and tympanic membrane
What 2 structures attach to the stapes?
Vestibular window (in contact with perilymph fluid) and incus
Where does the tensor tympani muscle insert?
Malleus
What nerve innervates the tensor tympani muscle?
Branch of trigeminal nerve
Where does stapedius muscle insert?
Stapes
What nerve innervates the stapedius muscle?
Stapedial branch of facial nerve
Where do both the tensor tympani and stapedius muscles originate?
Tympanic bulla
Name the bony structure that houses the cochea
Promontory (where cochlear and vestibular windows are located)
Describe the 3 layers of the tympanic membrane and their origin
Inner epithelium: originates from pharyngeal pouch
Central layer: fibrous connective tissue of pharyngeal wall
Outer layer: stratified squamous epithelium derived from ectoderm of first pharyngeal groove
What is the stria mallearis?
Outline of the manibrium of malleus
Where should a myringotomy be performed?
Caudal ventral quadrant of TM (pars tensa)
Which direction does the manubrium of the malleus face?
C-shaped and concave aspect of the C points rostrally
Where and in what direction does tympanic membrane regenerate?
Radially from the umbo pars tensa