Landmarks: sella (S), nasion (N), A point (A), B point (B), pogonion (Pog), hyoid bone (H), second cervical vertebra (C2), and fourth cervical vertebra (C4). X-axis (white line): constructed by drawing a line through nasion 7° up from SN line. Y-axis (white line): a line through sella (S) perpendicular to the X-axis. The measured angles: brown color, ANB angle; green color, (1) Or–Po–Pog angle, (2) Or–Po–H angle, (3) Or–Po–C2 angle; and yellow color, (4) Po-C2-Pog angle, (5) Po-C2-H angle, (6) Po–C2–C4 angle.