Eustachian tube

The eustachian tube is one of a pair of small canals that link the nasal canal to the middle ear. It allows the pressure on the eardrum to be equalized and also allows mucus to drain from the middle ear.
Upper respiratory tract infections and allergies can block one or both of the tubes leading to ear infections, particularly in children under the age of seven.
Eustachian tube at Wikipedia
Category:Anatomy