Fig. 1
From: 3-dimensional analysis of hard- and soft-tissue symmetry in a Chinese population
The three-dimensional coordinate system of hard-tissue (A) and soft-tissue (B). For the hard-tissue, the Y-Z plane (MSP) was set across the nasion point and perpendicular to the frontozygomatic suture line. The X-Z plane (horizontal reference plane) was set through the nasion point and parallel to Frankfurt horizontal plane which was set across the left orbitale point and bilateral porion points. The X-Y plane (coronal reference plane) was set through the nasion point and perpendicular to the above two planes. For the soft-tissue, The Y-Z plane (MSP) was set through the soft tissue nasion point and perpendicular to the line connecting the exocanthion points on the right and left sides. The X-Z plane (horizontal reference plane) was set through the nasion point and parallel to Frankfurt horizontal plane. The X-Y plane (coronal reference plane) was also set through the nasion point and perpendicular to the above two planes.