Anatomy of the Ear

The ear is a complex and delicate organ. It collects sound waves so you can hear the world around you. The ear also has a second function—it helps you keep your balance.

Your ear can be divided into 3 main parts. These are the outer ear, the middle ear, and the inner ear. The outer ear and middle ear help collect and amplify sound. The inner ear converts sound waves to messages that are sent to the brain. The inner ear also senses the movement and position of your head and body. It helps you maintain your balance and see clearly, even when you change positions.

Man's face showing inner ear structures.

Here is how the different parts of your ear work together to help you hear and stay balanced:

  • The mastoid bone surrounds the middle ear.

  • The external ear collects sound waves.

  • The ear canal carries those sound waves to the eardrum.

  • The eardrum vibrates from the sound waves, setting the middle ear bones in motion.

  • The middle ear bones (ossicles) vibrate, transmitting the sound waves to the inner ear. When the ear is healthy, air pressure remains balanced in the middle ear.

  • The eustachian tube helps control air pressure in the middle ear. 

  • The semicircular canals help maintain balance.

  • The vestibular nerve carries balance signals to the brain.

  • The cochlea picks up the sound waves and makes nerve signals. 

  • The auditory nerve carries the sound signals to the brain.

Cross section of ear showing outer, inner, and middle ear structures.

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