Face-bow

Frame extends from the region of TMJ or external acoustic meatus to a distance of 2-3 inches in front of the face.

This placement generally locates the rods within 5 mm of the true centre of the opening hinge axis of the jaw.

Snow attempted to give the occlusal plane an individual position also in this third dimension : and in order to achieve this he set about as follows.

was parallel with a plane extending from the bottom of the glenoid fossa and passing through the anterior nasal spine.

This plane cannot be determined directly on a living person; but it approximately corresponds with a line drawn from the upper part of the tragus to the lower edge of the nostril.