Ear canal
Meatus acusticus externus
Sensory (eye & ear)OrgansHeadLeft and right
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- What it is
- The external acoustic meatus: a slightly S-shaped tube from the concha to the eardrum. Its outer third is cartilage carrying hairs, sebaceous and ceruminous (wax) glands; the inner two-thirds run through the temporal bone under thin, hairless skin.
- Function
- Conducts airborne sound to the eardrum and, by its length, resonates at about 3 kHz to boost speech-range frequencies by 10-15 dB.
- Size
- About 25 mm long and 7 mm in diameter, narrowest at the bony isthmus.
- Clinical note
- Because the canal curves, clinicians pull the auricle up and back to straighten it before looking in with an otoscope (down and back in infants).