The tongue is an extremely important, complex and still not fully understood muscle that is the first part of the gastrointestional system. It plays a major part in feeding, oral hygiene, speech and craniofacial growth and development. The tongue is made up of 8 muscles that each function in a unique manner and collectively act together as one unit. Under the tongue a piece of tissue exists in virtually all humans and is referred to as a frenulum. This piece of tissue is a remnant from the embryologic development of the tongue and normal for all individuals to have some degree or frenulum present .
Tongue frenulums can be broken down into upwards of 5 degrees or catergories, but the most important aspect is functional impairment or impact on the tongue mobility and overall function. Terms like tongue tie or tethered oral tissue (TOT) are commonly used to describe these tight or restrictive pieces of tissue. The term slight or small tongue tie is a misnomer and does not depict how well or poorly the tongue is able to function. For the purposes of simplicity these can be broken down to functional and dysfunctional tongue frenulums.
A functional lingual frenulum will allow for proper movement and range of motion of the tongue. It will not restrict or negatively impact surrounding structures and may or may not be visually evident. If a tongue frenulum is seen, that does not mean it is necessarily a “tie” or restricting of the tongue motion or range. On the other hand, a tongue that is able to extend out, does not necessarily mean it is functional.
Many times the symptoms being experienced by the parent and/or the child and the actual feel of the frenulum are key in helping determine if the tongue frenulum is truly tied and impacting function. More anterior ties, or that attach closer to the tip of the tongue are easy to visually diagnose, but more posterior or submucosal frenulums are not always visually evident alone.
Some individuals will have a visually evident tongue tie or restriction, but may not presently experience any symptoms or problems. These cases are still important to assess and address due to longterm issues that may impact the child, which are discussed later. A complete assessment by a well-trained lactation consultant or medical professional should be conducted to ensure compensatory mechanisms are not masking underlying problems and putting the dyad at risk for future problems.
Figure 4 and 5: This is the exact same patient. The image on the left shows a submucosal tongue tie and on the right it is shown when upward pressure is placed on the tongue.
The frenulum is made up of fibrous tissue (Type 1 Collagen) that is equivalent to a rope. This tissue will stretch only about 3% and it is NOT a rubber band or elastic. The tongue will grow, gain more strength and mass as it is used after birth, but a restricted tongue will not spontaneously resolve in the important time period for nursing. Each frenulum will have varied lengths to it and a longer frenulum can allow a tongue to partially function, but a short and thicker frenulum, especially the submucosal variety, can have a detrimental effect on tongue mobility and function. The article below describes this from a histological standpoint.
Histology of the Lingual Frenulum
Once an embryo has been established and starts to grow inside the mother’s uterus an extremely sensitive and complex developmental process is underway.
The first few weeks of development (week 4-8 in utero) is when many of the structures of the mouth, heart and face develop and arise. When the tongue is developing in the first months in utero it is originally attached to the floor or bottom of the mouth. As the oral structures continue to develop, the tongue separates from the floor of the mouth and becomes free to move around. It is like the top layer (the tongue) peels up and off of the bottom layer (floor of mouth) to become less attached. In most individuals, the front of the tongue becomes free first and proceeds towards the back of the tongue to become released from the floor of the mouth, almost like a zipper. In some individuals, this process does not occur at all and leads to an anterior or complete tongue tie. The same process occurs to varying degrees in other individuals. They may have a portion of the frenulum remaining that starts half way under the tongue and continues back and these are considered posterior or submucosal frenulums. Again, the frenulum’s length, positioning and thickness can vary greatly, depending on how it developed in utero. All humans have some degree of frenulum under the tongue, the most important part is how well or poorly it functions in relation to the tongue.
There is some scientific evidence that tongue ties may have a genetic correlation and occur more frequently within certain families. These cases can be easier to diagnose given the familial history, but each infant and mother (collectively the "dyad") present unique challenges that needs to be fully assessed and not assumed.
We have to understand that as the tongue develops in the mouth, so do other structures that surround the tongue and can have a major impact on these other structures. The palate, or roof of the mouth, is influenced by the tongue as it develops. As the tongue starts to become more mobile in the developing fetus, it will elevate and push upwards and outwards on the palate and help gently round, flatten and push the palate out. The importance of the tongue mobility and shape of the palate will be discussed later to better explain why these are important in nursing and airway development.
Tongue ties come in assorted varieties, shapes, sizes and make-ups. Some are very easy to see and others are much more difficult to see and need to be physically felt and examined by someone with experience in recognizing, diagnosing and treating these issues. Tongue ties are very thin and attach to the lower jaw and the tongue will have a small indent at the tip. Ties can appear further back in the mouth and when the tongue is lifted a webbed appearance may be seen behind the bottom jaw (See Figure 1 and 2 below). This webbed appearance resembles the Eiffel Tower and restricts the full range of movement of the tongue. The most difficult types of ties to diagnose and treat are posterior or even further back in the mouth and under the tongue’s mucosal layer (submucosal). These ties are not easily seen and almost exclusively need to be felt with a finger and assessed through a thorough nursing history and digital sucking exam. These ties are typically thicker and denser in these posterior areas, resembling a guitar string or piano wire, as opposed to the more thin anterior variety that are more thin and almost transparent from a side view.
Figure 1, 2 and 3: These pictures show a variety of lingual frenulums or tongue ties in infants. Notice the varied thickness, degree of webbing, connection points with the tongue and into lower jaw and restriction to tongue elevation.