10.20 Hearing and Balance

10.20.2 Describe the basic anatomy (structure) of the ear.

The ear is composed of three main parts:

• the outer ear;
• the middle ear; and
• the inner ear.

Outer ear

The outer ear consists of:

• the pinna; and
• the ear canal.

The ear canal extends from the pinna to the eardrum

Middle ear

The middle ear is separated from the outer ear by the eardrum.

It contains three small bones called the ossicles:

• malleus;
• incus; and
• stapes.

The middle ear is also connected to the throat by the Eustachian tube.

Inner ear

The inner ear contains:

• the cochlea; and
• the vestibular system.

The vestibular system includes:

• the semicircular canals; and
• the vestibular sacs.

Key point

Outer ear — pinna and ear canal

Middle ear — eardrum, ossicles and Eustachian tube

Inner ear — cochlea and vestibular system

10.20.4 Describe the physiology (function) of the ear.

The ear detects sound waves, converts them into electrical signals, and sends these signals to the brain for interpretation.

It also plays an important role in balance and spatial orientation.

Outer ear

The outer ear collects sound waves and channels them down the ear canal towards the eardrum.