Outer Ear Anatomy & Disorders
The only portion of the pinna that is not cartilaginous.
Lobule/Ear lobe
The distance covered by one cycle of a propagating wave.
Wavelength
Where malleus attaches to TM.
umbo
The wall of the tympanic cavity that houses or protects the jugular vein.
Inferior wall
The opposition to sound flow through an acoustic system.
Acoustic impedance
The most common form of skin cancer caused by excessive sunlight exposure.
Basal cell carcinoma
The resonant frequency of the EAC.
3-4 kHz
The portion of TM that contains only the outer and inner layers.
Pars flaccida
A rounded prominence in the medial wall of tympanic cavity formed by the lateral projection of the basal turn of the cochlear.
Promontory
The gain in dB SPL caused by the areal difference between the TM and the stapes footplate.
25 dB SPL
This portion of the EAC contains the epithelial lining (skin) of that is thinner than anywhere else in the body.
Osseous portion
The sound source azimuth angle (between 0 and 180 degrees azimuth) that produces the largest interaural time difference.
90 degrees azimuth
The tube that is surgically inserted into the TM to help equalize pressure between the outer and middle ear.
Pressure equalization (PE) tube
A branch of the facial nerve that enters the middle ear through the posterior wall.
Chorda tympani nerve
The contraction of middle ear muscles that helps reduce the intensity of a sudden loud sound.
Acoustic reflex
Benign bony growth in the medial portion of EAC that is usually multiple and bilateral.
Exostosis
The acoustic effect caused by a sound with a wavelength that is shorter than the size of the head.
Head shadow effect
The ear that shows a 7 o’clock cone of light during otoscopy.
Left ear
A fracture line caused by temporal bone trauma that extends into the otic capsule.
Transverse fracture
The sensation of increased loudness of self-generated sounds such as vocalization when the ear canal is blocked.
Occlusion effect