The Outer Ear
The outer ear consists of the pinna and ear canal.
The pinna or, auricle is the external flap of skin that we can see. It serves to collect or ‘funnel’ sounds into the ear canal and help us know the direction of sound.
The ear canal varies in size and shape from person to person. It is about 2.5cm long in adults and finishes at the eardrum.
The canal produces ear wax or cerumen. Ear Wax accumulates in the ear canal and serves as a protective barrier to the skin from bacteria and moisture. Ear wax is normal unless it completely blocks the ear canal.
The Middle Ear
The middle ear consists of the eardrum membrane, an air-filled cavity and ossicular chain and the Eustachian Tube which joins the back of the nasal passages.
The eardrum, or tympanic membrane (abbreviated TM), is the dividing structure between the outer and middle ear. It is a very thin membrane is stretched across the ear canal and is quite stiff, but flexible.
Behind the eardrum is an air-filled cavity which houses the 3 middle ear bones- the hammer (malleus), anvil (incus) and stirrup (stapes). These 3 tiny bones or ossicles are connected forming a ‘chain’. The hammer is connected to the eardrum membrane on one end and the stirrup at the other.
The middle ear cavity is filled with air and is connected to the back of the nose and throat by the eustachian tube. The Eustachian tube is the middle ear’s air pressure equalizing system. It is normally closed but opens when we swallow or yawn, or when we blow our nose.
The Inner Ear
The inner ear consists of the semicircular canals, Cochlea and auditory pathway to the brain
The 3 loops at the top form the organ of balance, the semicircular canals, and the snail-shaped part are the organ of hearing, the cochlea.
The inner ear contains a fluid-filled cochlea that is lined with thousands of tiny hair cells.