Site-specific differences in vertebral spinous process inclination
- In the cervical vertebrae, the spinous processes are horizontal, but as one moves toward the lower thoracic vertebrae, they become more vertical. Therefore, in the thoracic vertebrae, when the trunk is bent backward, the spinous processes overlap and interfere with the backward bending.
| Flexion | Extension | Lateral flexion | Axial rotation |
Cervical vertebrae | 40˚ | 75˚ | 35-45˚ | 45-50˚ |
Thoracic vertebrae | 45˚ | 25˚ | 20˚ | 35˚ |
Lumbar vertebrae | 60˚ | 35˚ | 20˚ | 5˚ |