The semi-circular canals are three tiny circular tubes at right angles to each other which contain fluid and can sense when that fluid is moving in each of the three dimensions that make up our 3D space.
There are two sets of semi-circular canals; one set adjacent to each cochlea.
Nerve bundles coming from the semi-circular canals join together with your auditory nerve and carry balance signals to your brain.
Many people with hearing loss also have some degree of balance difficulties, since the vestibular (or balance) system and the auditory (or hearing) systems are so closely related.
Your brain gets two other sources of information to help with balance. These alternative sources of balance information can help someone with a severely impaired vestibular capablility function reasonably well, despite that loss.
The two other sources include: visual information and physical information Obviously, being able to see helps your brain know "which end's up" and what your motion is. But, your body can also get information about balance from feeling the pressure on parts of your body (like your feet and legs) that tell it where the ground is and whether you are balanced well on your feet.
Many audiologists also have specialized training and equipment to help diagnose and treat people with balance problems.