Ear drum perforation – Causes and Problems

Our ear and hearing is a most fantastic creation of nature. Sound waves that travel down our ear canal, vibrate our ear drum. This tightly stretched three-layered skin membrane will move. The three ear bones of our ear’s conducting system magnify this movement, and therefore the energy. This magnified energy moves the liquid of our inner cochlea, and their movement in turn, displaces sensory cells that create the electrical impulses that our brain finally understands as sound. Just think about how amazing this simple act of hearing is. Imagine how difficult it is to move the water in a cup just by gently blowing on it as you whisper!

This amplification phenomenon is made possible by our middle ear system that consists of our eardrum and ear bones. The ear drum which is made of a thin skin membrane, acts like a sail that picks up the wind energy of sound, moving the three ear bones that further amplify the energy. Nowhere else can engineers improve on this amplification system and the simplest analogy we have is the hydraulic lift pressure systems we have in our car braking system or in a car hydraulic lift of a garage!

So what happens if this system is broken as sometimes our eardrum can be broken or perforated. When this happens, less energy can be picked up, and naturally we hear less. Also our eardrum seals our sterile middle ear cavity from the bacterial outside world. So when there is a hole, however small it may be, if  irritant soapy water, or dirty contaminated fluid, enters through it into the middle ear, we end up getting a smelly ear discharge and a middle ear infection.

So what can cause us to have ruptured eardrums? Eardrums may perforate due to injury to them either from within or from the outside. Middle ear infections are the commonest infection in children; here pus is formed that bulges and painfully stretches the eardrum until in some cases, it bursts through. Usually these holes healed quickly, but sometimes if they are too large or the infection is not quick in settling, a permanent perforation may ensue. The eardrum can also be broken from the outside; this usually occurs from injury like a toothpick or ear bud, or sometimes from a slap or hit to the side of the head. Here the column of air in the ear canal suddenly acts like a bullet, breaking the eardrum from outside.

Irrespective of the cause, if there is a hole, the possibility of infection arising due to soiling from the outside is always a possibility. In addition, with the formation of a perforation in the eardrum, Mother Nature’s most efficient amplification system becomes less efficient, and the hearing is reduced.

The Chinese version of this article was published in Hong Kong Economic Journal on December 16, 2013.