From the Research
The normal adult tympanic membrane (eardrum) is a thin, translucent, pearl-gray or light pink oval membrane that separates the external ear canal from the middle ear, appearing concave with the umbo visible where the malleus attaches to its medial surface, and should be intact without perforations, retraction, bulging, or fluid behind it 1. The pars tensa forms most of the membrane and has a fibrous middle layer that gives it tension, while the smaller pars flaccida is located superiorly.
- A healthy tympanic membrane displays a cone of light reflection in the anteroinferior quadrant due to its angle relative to the ear canal.
- The membrane should be intact without perforations, retraction, bulging, or fluid behind it.
- Blood vessels may be visible radiating from the periphery, but they should not be prominently engorged.
- The normal tympanic membrane moves appropriately with pneumatic otoscopy, demonstrating good mobility. This structure is approximately 8-10 mm in diameter and 0.1 mm thick, serving as both a protective barrier and a crucial component for sound transmission from the external environment to the ossicular chain in the middle ear, as described in studies on the morphology of the human tympanic membrane annulus 2 and observations on tympanic membrane perforations and hearing loss 3. The natural course of most tympanic membrane pathology associated with otitis media in early life is favorable over time, suggesting an intrinsic repair capacity of the tympanic membrane 4, and treatment of large tympanic membrane perforations can be successful using either the underlay or over-underlay technique 5. However, the most recent and highest quality study on the topic, which is the 2020 study on the correlation of tympanic membrane perforation with hearing loss and its parameters in chronic otitis media 1, provides the most relevant information on the normal presentation of an adult tympanic membrane.