Using the vault hold, the examiner exerted a force over the great wings of the sphenoid bone with his index fingers. This force was in a frontal direction away from the fifth fingers which were gently immobilizing the areas over the occipital squama. It is essential that this force be applied as bilaterally equally as possible. The examiner's thumbs in contact with each other furnish valuable kinesthetic and proprioceptive cues during this testing procedure. Following the initiation of the motion, it was monitored to the restricted end point and rated on the 3 point scale (ease/restriction in response to the initiating force). A free anterior-posterior expansion motion (indicated by ease of motion in a frontal directional suggested the absence of compression.