Table 1.
Parameter definitions of the axis system for the jaw and head
| Axis |
Rotation (degrees) |
Positive angle |
Translation (mm) |
Positive translation | |
|---|---|---|---|---|---|
| Jaw | x | Tilt | Axial rotation left (chin tilts to left) | Anterior-posterior | Anterior translation mandible |
|
| |||||
| y | Opening/closing | Sagittal rotation (mouth opening) | Superior-inferior | Superior translation mandible | |
|
| |||||
| z | Lateral deviation | Coronal rotation left (chin moves to left) | Left-right | Left deviation mandible | |
|
| |||||
| Head | x | Lateral flexion | Axial rotation left (head tilts to left) | Anterior-posterior | Forward head |
|
| |||||
| y | Flexion/extension | Sagittal rotation (head/neck flexion) | Left-right | Head translation left | |
|
| |||||
| z | Rotation | Coronal rotation left (head rotates to left) | Superior-inferior | Superior translation head | |