This is the thin, delicate, quadrilateral plate of bone in the vertical plane. It projects superiorly from the angle it forms with the horizontal plate. It has two surfaces. The nasal surface contributes to the posterolateral wall of the nasal cavity, while the rough maxillary surface articulates with the medial wall of the maxilla.

Perpendicular comes from the Latin meaning to weigh carefully. This is from the Latin per- and pendere meaning to hang or weigh. Things were weighed by hanging from a vertical line. The term perpendiculum came to mean a plum line. Plate comes from the Greek platus meaning flat or broad. Its Latin equivalent is lamina.

Lamina perpendicularis ossis palatini