FMA Vertical Assessment — NDEB AFK MCQ

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ModerateOrthodonticsFMA Vertical AssessmentNDEB AFK

Which measurement on a cephalometric radiograph assesses the vertical facial pattern using the mandibular plane and the Frankfort horizontal?

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Correct answer: D — FMA (Frankfort-mandibular plane angle)

The FMA is measured between the Frankfort horizontal plane and the mandibular plane. Normal FMA is approximately 25° (±5°). Increased FMA indicates a hyperdivergent (dolichofacial/long face) pattern; decreased FMA indicates a hypodivergent (brachyfacial/short face) pattern. The vertical facial pattern influences treatment planning — dolichofacial patients are prone to open bite and should avoid extrusive mechanics; brachyfacial patients tend toward deep bite.

Reference: Proffit – Contemporary Orthodontics, 6th ed., 2019