Since the fact was known that mouth breathing resulted from the adenoid hypertropy causes malocclusion, many investigators have studied nasopharynx and adenoid in order to clatify the role in relation to the effect on face and coolustion and the development of arrway. The author analyzed 13 items in longitudinal cephalometric roentgenograms of 17 boys and 19 girls taken from the age of 7 to 12. The results were as follows. 1. The means and standard deviation for the measured items were obtained. 2. The continual growth of nasopharyngeal cavity was more affected by the height than the depth. 3. The size of adenoid was larger in males than in females, especially on R, D-AD2. 4. Airway percentage was highest in boys at age 10 and girls at age 9. 5. The items showed significant differentiation between males and females were airway percentage, posterior height, D-AD1, D-AD2, and R.
