Sound generally enters the inner ear through air conduction, which is the main way we perceive sound; Another secondary route is through cranial conduction.
The vibrations of the sound waves are collected by the auricle and pass through the external auditory canal to the tympanic membrane, causing mechanical vibrations of the tympanic membrane and the ossicular chain, which transmit the stapes foot plate through the vestibular window to the external lymph of the inner ear. This pathway is called air conduction, or air conduction for short. After the sound wave is transmitted to the lymph outside the inner ear, it is transformed into liquid wave vibration, which causes the basement membrane to vibrate, and the spiral hair cells located on the basement membrane bend the stecilia, causing the hair cell electrical activity, and the hair cell releases neurotransmitters to stimulate the axon terminals of the spiral ganglion cells, generating axonal action potentials. Nerve impulses travel along the brainstem auditory pathway to the auditory cortex center in the temporal lobes of the brain.
In addition, the air in the tympanic chamber can also vibrate through the round window membrane to produce a change in the lymphatic pressure of the inner ear, causing the basement membrane to vibrate. This pathway is secondary in normal people and only occurs when there is an obstruction or disruption of the normal conduction through the vestibular window, such as a large perforation of the tympanic membrane, or a disruption or fixation of the ossicular chain.