Using the vault hold, the occiput was gently held immovable by the examiner's fifth fingers while his index fingers (overlaying the great wings of the sphenoid bone) exerted a gentle symmetric force on a frontal plane first in a superior (or cephalad) direction, and then in an inferior (caudal) direction. As the vertical motion carries to its end point, it can be perceived that it possesses an arcing component which is directed posteriorly. Restrictions were rated as they limited the superior and/or inferior response to motion testing in those directions.