Table 1 Sagittal measurement indexes and annotations of the jaw

SNA(°)

The angle formed by S–N-A

SNB(°)

The angle formed by S–N-B

ANB(°)

The angle formed by A-N-B

NP-FH(°)

The posterior lower intersection angle of the intersection of the face plane NP (the line connecting N and Po) and the eye-ear plane FH (the line connecting P and O)

NA-PA(°)

The corner of the N to A connection (NA) and the extension of the Po to A connection (PA)