Under positive pressure, how does the tympanic membrane (TM) move?

The tympanic membrane (TM), or eardrum, is a thin, cone-shaped membrane that separates the external ear from the middle ear. When positive pressure is applied to the ear canal, it pushes against the TM. This pressure causes the TM to move inward, towards the middle ear. This inward movement is also a natural response to balancing pressure differences across the membrane, as the TM seeks to equalize the pressure between the external auditory canal and the middle ear space.

In the context of normal physiology, this movement is critical for maintaining proper hearing function, as it helps to facilitate wave transmission from the air to the fluid-filled cochlea after sound waves cause the TM to vibrate. These vibrations travel through the ossicles in the middle ear, reinforcing the need for the TM's movement during varying pressure conditions. Understanding this mechanism is essential for those involved in hearing health, as it underscores the importance of conditions that can affect pressure regulation, such as Eustachian tube function or ear infections.