Growth pattern of the rabbit nasal bone region. A combined serial gross and radiographic study with metallic implants.

Two radiopaque implants were inserted into each left and right nasal bone in 5 female rabbits. Ventrodorsal cephalometric radiographs were then taken in a specially designed head-holder at 6 and 16 weeks of age. From these radiographs separate tracings were made on matte acetate paper of the left and right nasal bone regions including the radiopaque implants. Since the implants maintained the same relationship to each other in each nasal bone, they served as stable reference sites. The markers of the 16-week tracing were superposed on the markers of the 6-week tracing. The difference in the two established outlines represented the changes in size and shape in two dimensions that had occurred during the 10-week period. Our purpose was to determine the relative growth activity at several borders. The mean increase was 6.79 mm at the proximal (posterior) border, 6.19 mm at the distal (anterior) border, 2.73 mm at the lateral border, 1.22 mm at the medial border. Thus, growth at the proximal and the distal borders was about the same and about twice that of the lateral border and about 5 times that of the medial border.