The ear, as it is commonly referred to, is medically and anatomically divided into the outer ear, middle ear and inner ear. As the name implies, inflammatory lesions in the middle ear are called otitis media. The middle ear is the part of the ear that is responsible for the conduction and amplification of sound. The middle ear consists mainly of the auditory tuberosities (there are three of them, the hammer bone, the anvil bone, and the stapes bone, which form a lever to amplify the sound-induced vibrations in the eardrum and then transmit them to the inner ear). The outer wall of the middle ear is the tympanic membrane, and the inner wall is the lateral wall of the cochlea. The middle ear has an eustachian tube in the front wall that leads to the nasopharynx, the natural tube that connects the middle ear to the atmosphere. A blockage of this tube can lead to stuffiness in the middle ear or fluid accumulation in the middle ear, which is why sometimes a cold (swelling of the nasal mucosa can block the eustachian tube) can cause otitis media. Otitis media is divided into secretory otitis media, purulent otitis media, middle ear cholesteatoma, and other special types of otitis media (tuberculous otitis media, AIDS otitis media, syphilitic otitis media, fungal otitis media, necrotizing otitis media, etc.) Why is it easy to get otitis media after a cold? The swelling of the nasal mucosa after a cold causes obstruction of the eustachian tube, which leads to fluid accumulation in the middle ear, thus causing secretory otitis media; and when children have poor resistance, it can also cause acute otitis media. Why do you get otitis media after swimming? Some patients have otitis media and tympanic membrane perforation. After swimming, water with bacteria enters the middle ear and the bacteria multiply in the warm and humid environment, thus causing middle ear inflammation.