In the head, the infant airway is divided into three parts: the nasopharynx, the oropharynx and the hypopharynx. The tongue is intricately related to the oropharynx. The posterior (back) of the tongue is also the anterior (front) wall of the oropharynx. This means that as the tongue moves forward in the mouth that the airway actually gets larger. If for some reason, like a tongue-tie, the tongue’s movement is restricted, the airway at the oropharynx would get smaller.
The tongue can only go as far forward in the mouth as the front top teeth allow. This means that when the maxilla (middle section of the face), and the top front teeth are allowed to develop properly, the tongue moves forward. This enlarges the infant airway. The converse is also true. If the maxilla is retracted by a restriction such as a tongue-tie, the front top teeth do not properly advance, the tongue is restricted and the airway shrinks.
When the face doesn’t develop properly, the problem is way more than aesthetic. A smaller airway is directly correlated to health issues from the beginning. Studies are beginning to show a correlation between tongue-ties and infant sleep apnea, which is tied to SIDS. As a child grows, a restricted airway increases the chances of asthma, allergies, and can decrease athletic performance. This is why it is so important for the tongue to be free to function properly, so the face will develop as it was designed to.