An increased SNA angle is indicative of which condition?

An increased SNA angle is indicative of which condition?

• A. Mandibular retrognathia
• B. Maxillary prognathism
• C. Mandibular prognathism
• D. Bimaxillary retrognathia

Answer: (B)

SNA tells us how forward the maxilla sits relative to the cranial base. It’s the angle formed by the sella-nasion line and nasion to point A. When the maxilla moves forward, the angle increases; when the maxilla is retruded, the angle decreases. Normal values are around 82 degrees, with some individual variation due to cranial base length. An increased SNA angle indicates maxillary prognathism—that is, the maxilla is positioned more anteriorly than normal. The other scenarios describe the mandible or the relative jaw relationship rather than the maxilla: mandible-forward (mandibular prognathism) affects the SNB angle, not SNA; mandibular retrusion or bimaxillary retrusion shifts are reflected more in ANB and SNB/SN-Mx relationships and can coincide with a normal or decreased SNA. Thus, the finding aligns with maxillary prognathism.

SNA tells us how forward the maxilla sits relative to the cranial base. It’s the angle formed by the sella-nasion line and nasion to point A. When the maxilla moves forward, the angle increases; when the maxilla is retruded, the angle decreases. Normal values are around 82 degrees, with some individual variation due to cranial base length.

An increased SNA angle indicates maxillary prognathism—that is, the maxilla is positioned more anteriorly than normal. The other scenarios describe the mandible or the relative jaw relationship rather than the maxilla: mandible-forward (mandibular prognathism) affects the SNB angle, not SNA; mandibular retrusion or bimaxillary retrusion shifts are reflected more in ANB and SNB/SN-Mx relationships and can coincide with a normal or decreased SNA. Thus, the finding aligns with maxillary prognathism.