Which cephalometric angle is used to determine the type of facial growth?

Which cephalometric angle is used to determine the type of facial growth?

• A. IMPA
• B. SNA
• C. SNB
• D. FMA

Answer: (D)

Vertical facial growth is best assessed by how steep the mandible sits relative to the cranial base. The FMA, the angle between the Frankfort horizontal plane and the mandibular plane, directly quantifies this. A larger FMA indicates a steeper mandibular plane and a tendency toward vertical (dolichofacial) growth, while a smaller FMA indicates a flatter mandibular plane and a horizontal (brachyfacial) growth pattern. Normal values are around 25 degrees; deviations above ~28 suggest vertical growth, and below ~22 suggest horizontal growth. The other angles—SNA and SNB reflect sagittal skeletal positions, and IMPA concerns incisor inclination—so they don’t reliably indicate the type of facial growth.

Vertical facial growth is best assessed by how steep the mandible sits relative to the cranial base. The FMA, the angle between the Frankfort horizontal plane and the mandibular plane, directly quantifies this. A larger FMA indicates a steeper mandibular plane and a tendency toward vertical (dolichofacial) growth, while a smaller FMA indicates a flatter mandibular plane and a horizontal (brachyfacial) growth pattern. Normal values are around 25 degrees; deviations above ~28 suggest vertical growth, and below ~22 suggest horizontal growth. The other angles—SNA and SNB reflect sagittal skeletal positions, and IMPA concerns incisor inclination—so they don’t reliably indicate the type of facial growth.