How We Hear

To understand hearing loss, we must first understand how hearing works. The ear is made up of 3 main parts:

  • Outer Ear
  • Middle Ear
  • Inner Ear

Outer Ear

The outer ear consists of the visible part of the ear (pinna), the ear canal and the ear drum. Sound waves are collected by the outer ear and are channelled toward the eardrum. The eardrum begins to vibrate.

Middle Ear

The middle ear is an air-filled space that contains the three smallest bones in the human body: the malleus, the incus and the stapes. These bones are attached to the eardrum on one side and the inner ear on the other side. The middle ear is also connected to the throat via the Eustachian tube, which makes sure the air pressure is the same on both sides of your eardrum, and allows your ears to “pop” when you’re flying in a plane or driving through mountains. The vibration of the eardrum causes movement of the three tiny bones in the middle ear. The movement of these bones transmits the eardrum vibrations to the inner ear.

Inner Ear

The inner ear consists of the cochlea and the vestibular (balance) system. The cochlea is a snail-shaped bone filled with fluid and thousands of tiny “hair cells” that process sound vibrations. Vibrations enter the cochlea and the fluid is set into motion, like a wave, and the hair cells move in response. When the hair cells move, they send electrical signals along the hearing nerve and toward the brain. The brain then processes these signals to help us understand what we have heard.