Voyage au centre de l'audition : spécialistes

> Ear: overview

Drawings and animations: S. Blatrix

The ear is divided in 3 parts: the external and middle ear transfer the sound waves to the inner ear, where they are transduced in neural activity.

Human external (E), middle (M) and inner (I) ear

This 3D animation shows the anatomical relationships between the three part of the Ear. The external ear (pink) is composed by the pinna and the ear canal, which is closed by the eardrum (tympanic membrane in blue). Eardrum and the cochlea (auditory inner ear) are linked by the ossicular chain of the middle ear. The cochlea transduces the physical stimulus (sound waves) into a neural message, which is sent to the CNS by the auditory nerve (jaune).

You can stop the animation to better figure these relationships.

See details on specific pages for external, middle and inner ear

The animated drawing below illustrates the functional relationships of the 3 parts of the ear.

Animated drawing showing how the sound waves in the external meatus are transferred to the inner ear fluids and to the basilar membrane (organ of Corti)

The sound wave moves the eardrum and attached ossicular chain. The stapes footplate, in the oval window, transfers the vibrations to the perilymphatic compartment (scala vestibuli) and to the inner ear structures. Depending on the frequency, the vibration has a maximum effect (resonance) at a different point along the basilar membrane, accounting for passive tonotopy.

Here, on the left, a high frequency sound affects a basal portion of the cochlea.

Here, a low frequency sound affects a more apical part of the cochlea.