The muscles of soft palate that control the opening and closure of Eustachian tube are not mature yet.

The Eustachian tubes of babies and children are shorter and flatter than those of adults, and their diameters are relatively smaller. However, the Eustachian tube is the major gateway that the middle ear gets infection. Its main functions are: to egulate the pressure in the middle ear, thus equalize the pressure difference between outer ear and middle ears to drain the secretion from the middle ear cavity to the nasopharynx and to ventilate the middle ear cavity with fresh air from the nasopharynx. Eustachian tube: regulating the pressure in the middle earĮustachian tube is the pipeline connecting the ear (middle ear) and throat (nasopharynx and rear side of nasal cavity).When the incoming sound is very loud, the ratio of sound transmitted by the lever system will be reduced by neural reflexes of the muscles in order to protect the inner ear from damage. Middle ear muscles are connected with some of the ossicles. This lever system amplifies the sound vibration and makes very soft sound audible. This results in vibration of fluid within the cochlea and hearing sensation arises. Sound vibration collected by the outer ear is transmitted to the oval window of the cochlea by the eardrum and the ossicular chain (consisting of three ossicles: malleus, incus, stapes) connected to it. Eardrum and ossicular chain: sound conduction and regulation.The most well-known structures in the middle ear are: tympanic membrane, ossicular chain and Eustachian tube. Middle ear disease may lead to serious complications as it is adjacent to the important parts in the head. However, the middle ear is easily affected by problems in the upper respiratory tract as it is connected with the nasopharynx (the upper part of the throat behind the nose). Since the middle ear is located deep in the head, it seldom attracts attention. It connects the outer and inner ear structures. When we look into the external auditory canal (ear canal), the middle ear is the air-filled space located behind the eardrum.

Nasopharynx auditory tube