Form vs Function: What Follows What?

Published: February 14, 2024

Imagine you are gifted a pair of shoes from a family member for your birthday. You realize it is one size smaller than your usual sizing. In your eagerness to make it work and not ruin your family’s present, you jam your foot in. Your toes curl under themselves, but your heel slips in. Success! Now the challenge is walking. You take the shoes “for a spin” and find that distributing the weight on the outer edges of the shoes is the most comfortable method for you to walk. You’re suddenly walking pigeon-toed, but you are walking, right?

This seemingly silly analogy demonstrates some of the struggles that our clients face by the time they see us. They are using compensations (i.e. the modified “pigeon-toed” walking) to function, but the Function is much less effective than it could be if the Form were correct in the first place. Here, the Form, or the structure of the shoe, elicits the recruitment of compensations. The human body has a wonderful adaptation mechanism to do what it is willed to do.

Function Follows Form
As in the above analogy, when the Form is not a good fit, suboptimal Function follows. We see this with narrow dental arches. When the tongue cannot fit inside the palate it sits low in the mouth, or even splays outwards beyond the dental arches (when it is meant to brace inside of the dental arch). “Sloppy” speech, preparation of a bolus, and initiation of the swallow may ensue.

When the teeth are in poor occlusion, we also see how the body adapts to the Form with changes to Function. For example, with end-to-end occlusion the “scissor” action during biting is affected. As a response to this malocclusion the tongue might sit on top of the lower central incisors and wedge under the food to assist with the biting process. An alternative is jaw shifting to haphazardly “cut” the food with teeth that are actually aligned in a “crushing-action” position. Additionally, you will likely witness the client bite food using the side of the mouth if the central incisors are not aligned correctly (the premolars become “promoted” to the role of “biting,” though their role is to crush food). These are functional oral compensations secondary to issues with structure/form; here Function follows Form.

Even enlarged tonsils can alter function, sometimes by coercing the tongue and/or the head to move and sit in a forward position to “get out of the way” and to open the airway. This is why orofacial myologists are excellent at observing these behavioral compensations and noticing them as “tip offs” to underlying, often structure-related, issues. In myo we need to understand how Form can initiate a self-perpetuating cycle that leads to responsive changes to Function (that can eventually affect Form again).

Form Follows Function
Form isn’t always the culprit that begins the chain-reaction for poor oral function; functional issues are often responsible for disturbances in form/structure too. We can look at low tongue rest with open mouth breathing, which can disrupt the growth and development of the oral structures, possibly leading to the following: open bites/crowded teeth and other malocclusions, steep jaw development, long facial growth, deficiency in midface growth, high palatal vault, narrow dental arches, etc. Then these issues can cycle back to influencing Function, such as distortions to speech sounds, poor mastication, poor bolus collection and swallowing efficiency, poor oral hygiene. The body’s structures are more malleable than we realize, and bone and teeth can and will move in response to changes in Function - just look at how noxious oral habits can deform the palate and move teeth!

Conflict vs Harmony?
The above examples might indicate to you that the Form and Function of myo clients are in a constant flux of disorder, where both conflict with one another. Another perspective would be to observe this interplay as less like “conflict” and more as “harmony”. The “push and pull” dynamic between Form and Function reminds us that the systems of the body are always trying to be harmonious to reach homeostasis. After all, survival is the end goal. This should be done using the least effort possible (since this conserves energy). That is why simply asking someone to shut their mouth when they mouth breathe is ineffective - it is likely they are mouth breathing as a means to survival, and there are likely underlying Form and Function issues that have triggered this adaptation.

Where do we begin?
Orofacial myologists are skilled detectives in understanding cause-effect relationships with oral structure and function. They identify the interplay between Form and Function in each client’s presentation and then plan treatment accordingly to the sequence of interventions that will most likely lead to treatment success. In some people Form takes precedence; in others, Function does. This is why we talk about eliminating barriers before beginning Orofacial Myology treatment since there can be such a flow-on effect when either Form or Function is disrupted. True function without compensations is the ideal goal, so the first approach taken should best target the main culprit of their myo dysfunction. Interdisciplinary discussions with professional providers involved in the case is advised. It often helps us to gain clarity with where to begin in less clear-cut situations, such as a client presenting with co-occurring enlarged adenoids, ankyloglossia, and an oral habit.

Form and Function can and do follow each other in myo, often moving muscle and bone as adaptation responses to maintain homeostasis. Whether Form or Function is addressed first is up to your clinical decision-making on a case-by-case basis. Just one piece of advice: in the end the client should still be breathing and should not suddenly be walking pigeon-toed!