Norms of size and annual increments for five anatomical measures of the mandible in boys from three to sixteen years of age

Abstract

Mixed longitudinal study of mandibular growth was conducted on fifty-two boys. The three-dimensional method of correcting for distortion and magnification of landmarks on the frontal and lateral cephalograms was used to obtain anatomically accurate dimensions of the mandible. Means and variability of size and annual increments were presented for ramus height, body length, maximum length, bigonial width, and bicondylar width. This paper corresponds to a similar one on girls and presents discussion of sex differences. A review of other studies on mandibular growth is included. Boys grew least in height, more in width, and most in length. Their circumpuberal increase was greatest for maximum length and least for bigonial width. In sex differences boys were found to be larger than girls at 3 years of age in all measurements but bigonial width. From age 3 years on, boys growth increments were larger and their postadolescent size reflected this in their larger overall size in each dimension. The boys' adolescent spurt was later and more pronounced in bigonial width, body length, maximum length, and ramus height.