Figure 1.

Marker placement and angle definition. (a) Craniovertebral angle was defined as the angle between the line connecting the tragus of the ear and the spinous process of the C7 and the horizontal line; (b) Frontal head tilt angle was defined as the angle between the midline of the head relative to the vertical line. Frontal shoulder angle was defined as the angle between the line connecting the left acromion and right acromion and the horizontal line; (c) Upper thoracic angle was defined as the angle between the line connecting the spinous processes of the T1 and T2 and the line connecting the spinous processes of the T6 and T7; (d) Scapular rotation angles were defined as the angle between the line connecting the superior and inferior scapular angles and the vertical line.