Table 2.

Posture-related parameters used in regressions. For regressions, all variables were calculated in the T1 coordinate system.

Dependent Variables
X and Y positions of hyoid bone (‘X_Hyoid’ and ‘Y_Hyoid’)	Position of point H1, with respect to the origin of the T1 coordinate system
Angle of hyoid bone (‘Angle_Hyoid’)	Angle of the line connecting point H1 and H2 (Figure 2B) with respect to the X-axis of the T1 coordinate system
Independent Variables
X and Y positions of head (‘X_Orbit’ and ‘Y_Orbit’)	Position of orbit marker (average of left and right orbit beads), with respect to the origin of the T1 coordinate system
X and Y positions of jaw (‘X_ChinTip’ and ‘Y_ChinTip’)	Position of chin tip marker, with respect to the origin of the T1 coordinate system
X and Y positions of vertebrae (C1–C7) (e.g. ‘X_C1’ and ‘Y_C1’)	Position of vertebral center (origins of the local vertebral body coordinate systems), with respect to the origin of the T1 coordinate system (Figure 3A)
Angle of head (‘Angle_Head’)	Angle of the line connecting orbit and tragus, with respect to the X-axis of the T1 coordinate system
Angle of jaw (‘Angle_Jaw’)	Angle of the line connecting the angle of jaw and chin tip, with respect to the X-axis of the T1 coordinate system
Angle of vertebrae (C1–C7) (e.g., ‘Angle_C1’)	Angle of the line connecting the midpoint of the anterior and posterior vertebral body (X axis of the local vertebral body coordinate system), with respect to the X-axis of the T1 coordinate system
Head and neck angular posture (‘Angle_ChinNeck’)	Angle from the chin tip to the intersection of chin and neck to the sternum (‘∠DEF’ in Figure 2A)