<prompt> Eustachian tube opens in?Inner earMiddle earOuter earLarynx  <response>: Ans. is b i.e., Middle ear Eustachian tube pharyngotympanic tube is a channel connecting the tympanic cavity middle ear cavity with nasopharynx. Therefore, ear infection can travel to throat through eustachian tube and vice-versa. Eustachion tube opens into anterior wall carotid wall of medial ear. 