How We Hear
Sounds are funneled into the ear canal by the outer ear. They hit the eardrum, causing it to vibrate. This vibration in turn causes the middle ear bones to vibrate. The third middle ear bone sits on the window to the inner ear so when it moves, the fluid in the inner ear or cochlea moves. This fluid movement makes the hair cells in the cochlea move which then sends a chemical message to the brain via the hearing nerve.