How does an enlarged pharyngeal tonsil interfere with nasal breathing?

The pharyngeal tonsils, commonly known as adenoids, are masses of lymphatic tissue located on the back wall of the nasopharynx, which serves as the primary passageway for air moving from the nose to the throat.123

When these tonsils become enlarged—a condition often resulting from childhood infections—they physically obstruct the nasal respiratory passage. This blockage prevents air from flowing freely through the nose, forcing the individual to rely on mouth breathing. In addition to hindering nasal respiration, this obstruction can interfere with sinus drainage and block the eustachian tubes, which may lead to secondary sinus and middle-ear infections. In children, chronic mouth breathing caused by this obstruction can also impact the development of facial bones.12