Which cephalometric measurement reflects maxillary position relative to the cranial base?

Which cephalometric measurement reflects maxillary position relative to the cranial base?

• A. SNA reflects maxillary position relative to cranial base.
• B. SNB reflects mandible position relative to cranial base.
• C. ANB indicates maxillo-mandibular discrepancy.
• D. Wits appraisal indicates cranial base asymmetry.

Answer: (A)

Maxillary position relative to the cranial base is assessed by the SNA angle. This cephalometric measure uses the cranial base reference line (Sella-Nasion) and the maxillary point A line (Nasion-A). The angle between these lines indicates how far forward or backward the maxilla sits on the cranial base: a larger angle means the maxilla is more protrusive, a smaller angle means it is retrusive. Typical value is around 82 degrees, and deviations help identify maxillary prognathism or retrognathism. In contrast, SNB evaluates the mandible’s position relative to the cranial base; ANB reflects the relative sagittal relationship between the maxilla and mandible; and Wits appraisal assesses jaw disharmony using projections on the occlusal plane, not the maxilla’s position relative to the cranial base.

Maxillary position relative to the cranial base is assessed by the SNA angle. This cephalometric measure uses the cranial base reference line (Sella-Nasion) and the maxillary point A line (Nasion-A). The angle between these lines indicates how far forward or backward the maxilla sits on the cranial base: a larger angle means the maxilla is more protrusive, a smaller angle means it is retrusive. Typical value is around 82 degrees, and deviations help identify maxillary prognathism or retrognathism.

In contrast, SNB evaluates the mandible’s position relative to the cranial base; ANB reflects the relative sagittal relationship between the maxilla and mandible; and Wits appraisal assesses jaw disharmony using projections on the occlusal plane, not the maxilla’s position relative to the cranial base.