which part of the ear separates the middle ear from the inner ear
Inner ear In the middle ear, the energy of pressure waves is translated into mechanical vibrations by the three auditory ossicles. Pressure waves move the tympanic membrane which in turns moves the malleus, the first bone of the middle ear. The malleus articulates to incus which connects to the stapes. The footplate of the stapes connects to the oval window, the beginning of the inner ear. When the stapes presses on the oval window, it causes the perilymph, the liquid of the inner ear to move. The middle ear thus serves to convert the energy from sound pressure waves to a force upon the perilymph of the inner ear. The oval window has only approximately 1/18 the area of the tympanic membrane and thus produces a higher pressure. The cochlea propagates these mechanical signals as waves in the fluid and membranes, and then converts them to nerve impulses which are transmitted to the brain.[3]
Eustachian tube The Eustachian tube /juːˌsteɪ.ʃən/, also known as the auditory tube or pharyngotympanic tube,[1] is a tube that links the nasopharynx to the middle ear. It is a part of the middle ear. In adult humans the Eustachian tube is approximately 35 mm (1.4 in) long and 3 mm (0.12 in) in diameter.[2] It is named after the sixteenth-century anatomist Bartolomeo Eustachi.[3]