Sn/GoGn angle

The Sn/GoGn angle is a measurement used by orthodontists to assess the relationship and growth patterns of the lower jaw (mandible) and forehead (skull). It is formed between two lines: one drawn along the lower edge of the forehead (Sella-Nasion line) and another along the lower jaw's growth direction (Gonion-Gnathion line). This angle helps determine whether the lower jaw is protruding, retruded, or aligned properly, which is important for diagnosing bite issues and planning orthodontic treatment. A typical value indicates a balanced relationship, while deviations can suggest specific growth patterns or skeletal discrepancies.