In vertical growth patterns, the FMA angle would typically be described as which of the following?

In vertical growth patterns, the FMA angle would typically be described as which of the following?

• A. It is reduced
• B. It is increasing
• C. It does not change
• D. It remains constant

Answer: (B)

In vertical growth patterns, the mandible tends to rotate downward and backward as the face lengthens. The FMA is the angle between the Frankfort horizontal plane and the mandibular plane, so when the mandible rotates clockwise, the mandibular plane tilts more steeply relative to Frankfort, making this angle larger. That’s why the FMA is described as increasing in vertical growers. If growth were horizontal, the mandible would rotate less steeply and the FMA would tend to decrease; in patterns with little change, the angle may stay similar, but the hallmark of vertical growth is an increasing FMA.

In vertical growth patterns, the mandible tends to rotate downward and backward as the face lengthens. The FMA is the angle between the Frankfort horizontal plane and the mandibular plane, so when the mandible rotates clockwise, the mandibular plane tilts more steeply relative to Frankfort, making this angle larger. That’s why the FMA is described as increasing in vertical growers. If growth were horizontal, the mandible would rotate less steeply and the FMA would tend to decrease; in patterns with little change, the angle may stay similar, but the hallmark of vertical growth is an increasing FMA.