ENT Flashcards
External Ear
Auricle
External auditory canal
Tympanic membrane
Middle Ear
Ossicles Eustachian tube Tympanic cavity Tensor tympani muscle Stapedius muscle
Inner ear
Cochlea
Vestibule
Semicircular canal
Nose
Nostrils
Nasal septum
Perinasal sinuses
Maxillary
Ethmoid
Sphenoid
Frontal
structures are continuous from
external ear through pharynx/larynx
Primary functions of middle and external ear
hearing
Primary functions of inner ear
hearing + balance
The only separation between the external ear and the sinus cavity
tympanic membrane
Auricle blood supply
Posterior auricular artery (primary)
Anterior auricular branches of temporal artery
Auricle innervation
auriculotemporal nerve (comes from superior anterior)
lesser occipital nerve
greater auricular nerve (these two come from posterior inferior)
Concha & external-most meatus innervation
auricular branch of vagus nerve
Auricular hematoma
shearing force applied to the auricle causes separation of perichondrium and cartilage layer
Perichondrium
active layer
composed of chondrocytes, chondroblasts, and fibroblasts
Where does an auricular hematoma normally occur?
between the helix and antihelix
You must apply ___ ____ or the hematoma will reoccur
compression dressing
Best outcomes for hematoma drainage
less than 12 hours after it occured
The outer portion of the external acoustic meatus is ___ (1/3) and the inner portion is ____ (2/3)
outer = cartilaginous inner = osseous
Where are cerumen glands (modified apocrine glands) found?
inside the external acoustic meatus
Main function of the external acoustic meatus
transmit sound waves from the auricle and protect the tympanic membrane
External acoustic meatus innervation
facial nerve
auricular branch of vagus nerve (Arnold’s reflex)
auriculotemporal nerve (v3)
Why is otitis externa a serious problem if it involved a portion of the bone?
osteomyelitis is possible
In what patient population is severe otitis externa most common?
diabetics
Osteomyelitis in the setting of otitis externa
mastoiditis
Otitis externa
Infection of the auditory canal
Pseudomonas is main cause
Usually polymicrobial
Common symptoms:
Ear pain, discharge, pruritus, pain when you touch tragus or helix
The middle ear is directly connected to the ___ ___ and therefore the ___ ____
nasal cavity; external atmosphere
Primary function of the tympanic membrane
transmit the sound waves to the ossicles and eventually to the oval window; acts directly on the malleus
Externally, the TM is covered by
keratinized squamous epithelium (layer of skin)
Internally, the TM is covered by
non-keratinized squamous epithelium (mucosa)
cartilage is in btwn the inner and outer layers
