What structure separates the middle ear from the inner ear?

The structure that separates the middle ear from the inner ear is the oval window. This small, membrane-covered opening serves as a critical interface between the two ear regions. When sound waves travel through the auditory canal and vibrate the eardrum, these vibrations are transmitted through the bones of the middle ear (ossicles) to the oval window.

As the oval window vibrates, it creates waves in the fluid-filled cochlea of the inner ear, which ultimately stimulates sensory hair cells and enables hearing. The oval window's ability to transmit sound vibrations is essential for the conversion of mechanical energy into neural signals that can be interpreted by the brain.

In contrast, the auditory canal is responsible for directing sound waves toward the eardrum, while the cochlea is the structure that converts those vibrations into nerve impulses, and the round window acts to relieve pressure in the inner ear but does not separate the middle ear from the inner ear.