In order to best understand how hearing loss can develop, it is useful to quickly look at how the human works. By understanding the function of each part of the ear, we can better understand how hearing is affected when those parts are not functioning normally.
Sound enters our ear at the Pinna, which is the visible part of the ear on the outside of our head. The Pinna is designed to collect sound waves and funnel them down the Ear canal towards the Tympanic membrane (eardrum). Together the Pinna and Ear canal are referred to as the outer ear.
The middle ear starts with the Tympanic membrane. As sound waves travelling down the Ear canal reach the Tympanic membrane, it vibrates like a drum. Behind the eardrum is an air-filled space containing three tiny bones, the smallest bones found anywhere in the human body. The vibrations in turn cause these bones to vibrate. The Middle Ear consists of the eardrum these tiny bones (Malleus, Incus and Stapes) and the air pocket in which they reside.
The cochlea and the semi-circular canals are our organ of both hearing and our sense of balance. The cochlea, semi-circular canals and the cochlear nerve (auditory nerve) comprise the parts of the Inner Ear. Sound passes to the Inner Ear via the vibrations of the Middle Ear bones, which are connected to the Cochlea at one end. Thousands of tiny sensory hair cells within the Cochlea convert the vibrations into an electro-chemical signal that’s carried by the auditory nerve to the brain, where sound is processed and interpreted.