The Eustachian tube is a narrow and short passage which joins the middle ear space with the cavity of the nose. This acts to drain the body's middle ear cavity of fluid and allows the pressure on either side of the drum to equalize. This maximises the vibration of the tympanic membrane, allowing you to hear very quiet sounds.
If the tube becomes blocked the middle ear may become full of liquid, a condition known as glue ear. The fluid may become infected requiring multiple courses of antibiotics. A grommet may be fitted to the eardrum to ventilate the middle ear space in this case, preventing the fluid accumulating. This is a tiny bobbin with a hole through the centre. Those with a perforated eardrum may benefit from wearing earplugs to protect their middle ear from water and infections.
If the Eustachian Tube isn't working properly it can lead to problems. Eustachian Tube Dysfunction is a common problem which can be caused by having a cold, enlarged tonsils or adenoids. Allergy is another common cause. The result is that the pressure in the middle ear space doesn't equalise with the outside world. This causes the eardrum to stretch, resulting in pain if there is a change in pressure. If the pressure gradient is high enough then the drum may tear. This can be very painful. Fortunately most of the causes of Eustachian Tube Dysfunction can be treated and the effect of the problem reduced.
The tympanic membrane may tear if exposed to extremes of pressure. Thankfully it usually heals in four to six weeks. It is worth getting a medical specialist or doctor to check it has healed by examining the ear with an otoscope. If the tear fails to heal it may need patching by an Ear, Nose and Throat specialist. Without this a persistent perforation may remain.