Inner Ear
Studies on the Human Ear

The Inner Ear

The inner ear is a hard bony structure containing six sensory organs, five for maintaining balance, and one for hearing. The inner ear is tipped slightly forward on its axis, and is located just behind the temporal bone on either side of the head.

When sound waves in the air press against the eardrum, the three bones of the middle ear transmit sound to the part of the inner ear which is responsible for hearing, known as the cochlea.

The cochlea is about the size of a large pea and consists of a set of narrow channels or tubes coiled in the shape of a spiral. When uncoiled, the entire structure is 3.2 centimeters, or one-and-a-quarter inches long.

The cochlea occupies a little less than half of the space in the inner ear.

The inner ear also contains the semicircular canals and otolith organs which are responsible for keeping our balance against the force of gravity, and for maintaining straight-line movements.

The outer and middle ear are filled with air, while the inner ear contains perilymph fluid.

The fluid of the inner ear interacts with both the oval window and the round window, each of which is located at the wall separating the inner ear from the middle ear.

The fluid-filled space containing the various parts of the inner ear is known as the vestibule.