What a Tongue Tie Actually Is
The frenulum is a band of connective tissue that attaches the underside of the tongue to the floor of the mouth. In a normal attachment, this band is thin, elastic, and positioned far enough back that it allows the tongue to move freely, to reach the roof of the mouth, to move laterally, to lift and extend. That full range of motion is not just useful for speaking and eating. It is essential for proper oral rest posture, where the tongue should sit lightly against the upper palate with the mouth closed and the airway unobstructed.
When the frenulum is too short, too thick, or attached too far forward, including in a posterior position that is not always visible without a careful functional evaluation, it limits that range of motion. The tongue cannot lift properly. It cannot reach the palate. It sits on the floor of the mouth instead, which over time influences how the palate develops, how the jaw grows, how the airway is shaped, and how the person breathes, speaks, swallows, and sleeps.
A lip tie or buccal ties, which are a tight or restrictive frenulum attaching the upper or lower lip to the gum, often co-occurs with tongue tie and carries its own set of functional consequences, particularly for infants who are breastfeeding.