Otoscopes are classified as otoscopes, electro-otoscopes, and cylindrical otoscopes
1) otoscopes can only see a part of the tympanic membrane, so otoscopes should not be placed more than one-third of the external auditory canal
2) electro-otoscopes to check for subtle lesions that are imperceptible with the naked eye
3) cylindrical otoscopes can be used to observe tympanic membrane mobility and small perforations on the tympanic membrane.
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