Ear

The middle ear transmits sound from the outer ear to the inner ear. The middle ear consists of an oval, air-filled space approximately 2 cubic cm in volume. The middle ear can be thought of as a room, the outer wall of which contains the tympanic membrane. The back wall, separating the middle ear from the inner ear, has two windows, the oval window and the round window. There is a long hallway leading away from the side wall of the room, known as the eustachian tube. The brain lies above the room and the jugular vein lies below. The middle ear is lined entirely with mucous membrane (similar to the nose) and is surrounded by the bones of the skull.