ENT exam Flashcards
Tympanic membrane - location
End of the ear canal
marks the lateral limit of the external ear
Function of external ear
Captures sound waves for transmission into the middle an inner ear
Middle ear contents
- air filled
- contains the ossicles (malleus, incus, and stapes)
Function of middle ear
Transform sound vibrations into mechanical waves for the inner ear
Eusachian tube
From the middle ear
Proximal part connects the middle ear to the nasopharynx
Ossicles visible through the tympanic membrane
- malleus (handle and short process)
- incus *sometimes seen through the ear drum
Umbo
- point where the eardrum meets the tip of the malleus
- will see the cone of light at this region
Location cone of light
- at the umbo
- fans downward and anterioly
Pars flaccida
Portion of the eardrum located above the short process of the malleolus
Pars tensa
Remainder of the ear rum located below the short process of the malleolus
Separation pars flaccida and pars tensa
Anterior and posterior malleolar folds which extend obliquely upward from the short process
Inner ear components
- cochlea
- semicircular canals
- auditory erve
Function of inner ear
- movements of the stapes vibrate the perilymph in the semicircular canal and the hair cells and endolymph in the ducts of the cochlea
- produces electrical nerve impulses
- these re transmitted by the auditory nerve to the brain
How to access the function of the inner and middle ear
Most of middle and all of inner inaccessible to direct examination
Asses by testing auditory function
Hearing pathways
1) Conductive phase (external ear –> middle ear)
2) Sensorineural phase *cochlea and cochlear nerve)
Conductive hearing loss
-disorders of the external and middle ear external ear causes: -infection (otitis externa) -trauma -squamous cell carcinoma -benign bony growth (exostoses, osteomas) Middle ear causes: -congenital conditions -benign cholesteastomas -otosclerosis -tumors -perforation of tympanic membrane
Sensorineural hearing loss
-disorders of inner ear
-caused by :
congenital/hereditary conditions
presbycusis
viral infections (rubella, CMV, menieres disease)
noise exposure
acoustic neuroma
Equilibrum and the ear
The labrynth of three semicircular canals in the inner ear senses the position and movements of the head and helps to maintain balance
Assessment of the auricle
- deformities
- lumps
- skin lesions
- if ear pain move auricle up and down and press tragus, and press behind the ear firmly
Tug test
movement of the auricle and tragus is painful in acute otitis externa but not otitis media
Signs of pain due to otitis media
-pain behind the ear may be present
Visualizing ear canal and drum
- use otoscope with the largest ear speculum the canal will accomodate
- pull the auricle upward and backward and slightly away from the head
- direct the speculum down and forward through the hairs
Exostoses
Non tender nodular swellings covered by normal skin deep in the ear canals
Non malignant overgrowths
May obscure the drum
Inspection of ear canal
-note discharge, foreign bodies, redness/swelling of skin
-
Ear canal in otitis externa
- canal swollen narrowed, moist, pale and tender
- may be reddened
Ear canal in chronic otitis externa
Skin of the canal is thickened red and itchy
Inspection of the ear drum
-note its color and contour
Purpose of cone of light
helps to orient
