What condition is suggested if the SNA angle is less than 80?

When the SNA angle is measured to be less than 80 degrees, it indicates a retrognathic mandible. The SNA angle is a crucial cephalometric measurement used to evaluate the anteroposterior positioning of the maxilla in relation to the cranial base. A lower SNA angle suggests that the maxilla is positioned further back, potentially in relation to the mandible, which often results in a backward positioning of the entire facial profile.

In cases where the SNA angle falls below the threshold, it demonstrates a skeletal relationship where the mid-facial structures may not be adequately projected forward relative to the cranial base, contributing to a retrognathic profile. This positioning can lead to aesthetic concerns as well as functional problems, particularly in occlusion.

Understanding the implications of the SNA angle is essential in orthodontics and orthognathic surgery for diagnosing and planning treatment for patients presenting with discrepancies in dental and skeletal relationships.