Physics of the Tympanogram
Hover over any of the tympanogram's elements to learn more about its meaning and significance.
Tympanograms are classified, for ease of discussion, by the following rules:
|A||Peak compliance > 0.2 ml near 0 daPa middle ear pressure (MEP)|
|A'||Peak > 0.2 ml MEP -10 daPa to -99|
|A+||Peak > 0.2 ml MEP > +50 daPa|
|As||Peak < 0.2 ml MEP -99 daPa to +49 daPa|
|C1||Regardless of Peak MEP -100 daPa to -150 daPa|
|C2||Regardless of Peak MEP -151 daPa to -200 daPa|
|C3||Regardless of Peak MEP < -201 daPa|
|B||No Peak anywhere on the tracing|
|Read the cases below and think about how the
tympanogram would be affected. When you are done, display the tympanogram for each
case to see how close you came.
A two-year-old boy who comes to the office for a well-child visit. Mother thinks the child is not hearing as well as he should.
Examination of the tympanic membranes reveals normal color and mobility on pneumatic otoscopy. You check a tympanogram to assure yourself that no fluid is present in the middle ear.
A one-year-old girl with bilateral pressure equalizing tubes. She has had recurrent infection in the left ear, and you suspect that the pressure equalizing tube may be obstructed.
You check a tympanogram, paying particular attention to the shape of the curve and the external canal volume.
An eight-month-old boy with acute onset of pain in the right ear.
The ear appears red and you have some difficulty defining the structures.
A three-year old girl who comes back for a recheck on her right ear, six weeks following an acute ear infection.
The tympanic membrane is dull and non-erythematous. The landmarks are easily visualized.