The lateral wall of Nesofaring starts at the end of the turbinates. one.two five centimeters behind the posterior border of the inferior turbinate is the opening of the eustachian tube. Eustachian tube lateral one third part towards the medullary is bony, medial two thirds cartilage is. The eustachian tube makes an angle of forty five degrees with the horizontal. The angle develops at six to seven years of age.