What skeletal position is assessed by the SNA angle in a cephalogram?

The SNA angle is a critical measurement used in cephalometrics to evaluate the anteroposterior position of the maxilla relative to the cranial base. Specifically, it assesses whether the maxilla is positioned normally, protrusively, or retrognathically.

When the SNA angle is increased, this indicates that the maxilla is positioned more protrusively than typical, often contributing to an aesthetics that may require orthodontic intervention. Conversely, a decreased SNA angle suggests that the maxilla is retrognathic, meaning it is set back relative to the cranial base.

Therefore, while SNA primarily indicates a protrusive position when elevated, it can also help identify normal and retrognathic relationships based on its values. The fact that it can indicate a range of positions means that a comprehensive understanding of SNA helps orthodontists determine treatment strategies for various skeletal relationships, hence leading to the understanding that protrusiveness is a significant and highlighted aspect of this angle's assessment.