SNA angle

The SNA angle is a measurement used by orthodontists to assess the forward or backward position of the upper jaw (maxilla) relative to the base of the skull. It is formed by three points: Sella (middle of the skull), Nasion (point where the nose and forehead meet), and A-point (deepest point in the curve of the upper jaw). By measuring this angle, dentists can determine if the upper jaw is protrusive, retrusive, or normally positioned, which helps in diagnosing facial growth patterns and planning orthodontic or surgical treatments.