Fig. 2

Measurement of cervical vertebrae 2A shows the distance from the tip of posterior tubercle of atlas to posterior wall of vertebral foramen; 2B shows the distance from the tip of spinous process of C2 to the anterior wall of the lamina of vertebral arch, the tip of spinous process is asymmetrical; 2C shows the distance from the tip of spinous process of C6 to the anterior wall of the lamina of vertebral arch, the spinous process deviates from midline; 2D shows the distance from the tip of spinous process of C7 to the anterior wall of the lamina of vertebral arch, the tip of spinous process is asymmetrical