Which muscles typically display hypoactivity in individuals with a hyperdivergent phenotype?

In individuals with a hyperdivergent phenotype, there is typically an increased vertical dimension and a tendency for the mandible to be positioned further inferiorly and posteriorly. This condition often results in a functional adaptation of the masticatory muscles.

The masseter and medial pterygoid muscles are involved in elevating the mandible and are generally more activated in individuals with a hyperdivergent pattern. However, in this phenotype, these muscles may not be as active as they are in individuals with a more balanced or normodivergent growth pattern. The increased vertical growth and posteriorly positioned mandible can lead to a compensation where these muscles are not required to exert as much force during closure, leading to their hypoactivity.

Additionally, while lateral pterygoid involvement is critical for mandibular movement, it tends to demonstrate more activity in cases where functional shifts and adaptations are at play. Therefore, hypoactivity is more pronounced in the masseter and the medial pterygoid, making this choice the best representation of the muscular characteristics typically observed in individuals with a hyperdivergent phenotype.