What two planes form the mandibular plane angle?

The mandibular plane angle is specifically formed by the intersection of the mandibular plane and the SN plane (Sella-Nasion plane). The mandibular plane is typically defined by a line that runs along the inferior border of the mandible, capturing the orientation of the lower jaw, while the SN plane is created from the sella (the mid-point of the sella turcica in the skull) to the nasion (the bridge of the nose). This angle is an essential reference in cephalometric analysis, as it helps in assessing the orientation and position of the mandible in relation to the cranium.

By using these two planes to establish the mandibular plane angle, practitioners can systematically evaluate skeletal relationships and make informed decisions regarding orthodontic treatment and jaw positioning. The correct identification of these two planes is vital for accurate diagnosis and treatment planning in orthodontics and other dental specializations.