Growth of the mandible in adolescent pigtailed macaques (Macaca nemestrina)

Growth of the macaque mandible during adolescence is described using serial lateral cephalographs of 34 male and 23 female Macaca nemestrina. Tantalum implants were placed in the mandibles of 18 of these animals in order to determine the pattern of bone remodeling during the adolescent period. Linear dimensions of the male mandible are best described by the formula: Y = A + B (age), whereas Y = A + B (log₁₀ age) best describes growth of the female mandible during adolescence. A comparison of the two growth curves show that males grow for a longer period of time and that this expanded growth period contributes in producing a highly sexually dimorphic mandible. Although the mandible undergoes a rapid increase in size, the basic shape changes very little. During the adolescent period, both mandibular and postcranial dimensions undergo a growth spurt. The maximum acceleration of the spurt is reached between 4.0 and 5.0 years in males and between 3.0 and 4.0 years in females. The magnitude and duration of the male growth spurt also contributes to the size sexual dimorphism.