SNB Angle
Also written as: SNB — Sella-Nasion-Point B Angle
A cephalometric angle measured from Sella to Nasion to Point B, indicating the anteroposterior position of the mandible relative to the cranial base.
Full Definition
The SNB angle is formed by the intersection of the Sella-Nasion line and a line drawn from Nasion to Point B (the deepest point on the anterior surface of the mandibular symphysis). It quantifies the sagittal position of the mandible relative to the cranial base, with a normative value of approximately 80° in adults. An SNB below the norm suggests mandibular retrusion, while an elevated SNB suggests mandibular protrusion. Editors reviewing cephalometric data should confirm that SNB is reported alongside SNA and ANB to provide complete skeletal context. The SNB must not be confused with the SNB used in unrelated medical contexts.
Usage
Usage note: Report SNB in degrees (°) alongside SNA. Avoid presenting SNB in isolation without the corresponding SNA value.
In Context
- "The patient's SNB angle of 76° confirmed mandibular retrusion requiring orthopedic correction." — Orthodontic treatment plan
- "The manuscript incorrectly labelled the SNB angle as the SNA angle; this must be corrected before publication." — Manuscript peer review