The three-dimensional changes in the bone and the ratio of soft tissue to bone movement were investigated in a group of 17 Skeletal II patients following orthognathic surgery. CT scans were taken for each patient pre-operatively and 1 year post-operatively. The scans were superimposed, radial measurements calculated, and the changes illustrated by two separate colour scales. There was a constant ratio of movement over the maxillae with the central part of the upper lip being moved in a 1:1 ratio, increasing to a 1.25:1 ratio over the canine regions and 1.5:1 ratio over the paranasal areas. In the mandible there was a constant ratio of 1.25:1 over the chin, mentalis, and canine regions bilaterally. The ratio reduced to 1:1 over the body of the mandible.