The ear can be broken into three sections.
The first is the outer ear which is the part you see called the pinna as well as the ear canal.
Next is the middle ear, which is a tiny chamber that houses the tiny ear bones—the malleus, incus, and stapes.
And finally there’s the inner ear, which contains very special tissue structures called the cochlea which converts sound waves into electrical impulses for the brain and the semicircular canals which help with balance.
Between the outer and middle ear is an eardrum, also called the tympanic membrane, so no air passes between the two areas.
But the middle ear does have another possible outlet, called the eustachian tube which acts like a valve connecting the middle ear to the nasopharynx.
This tube has three main functions—equalizing pressure across the tympanic membrane, protecting the middle ear from reflux of fluids going up from the nasopharynx, and clearing out middle ear secretions.
Eustachian tube dysfunction describes situations when one or all of these functions aren’t happening normally.
In an adult, the eustachian tube is a roughly 4 centimeter long part-bone, part-cartilage canal that’s surrounded by four key muscles: the tensor veli palatini, the levator veli palatini, the salpingopharyngeus, and the tensor tympani, and it’s those first two that help a lot with opening up the tube.