MASSETER MUSCLE THICKNESS IN GROWING INDIVIDUALS AND ITS RELATION TO FACIAL MORPHOLOGY

It is widely accepted that an interaction exists between masticatory m uscle function and craniofacial growth. In adults, correlations have b een found between facial dimensions and jaw-muscle cross-sectional are a, and between facial dimensions and masseter muscle thickness. Little is known about growth of the human masticatory muscles and its relati on with facial dimensions at different ages. In 329 Creek individuals, aged 7-22 yr, masseter muscle thickness was measured by ultrasonograp hy. Muscle thickness was related to age, stature and weight, and to fa cial dimensions, measured by means of anthropological calipers. Muscle thickness was statistically assessed by univariate analysis of varian ce, after the males and females had been divided into three age groups . Facial dimensions were assessed by multivariate analysis of variance , age being considered as a covariate. The relation between muscle thi ckness and facial dimensions was subjected to stepwise multiple regres sion analysis. Masseter muscle thickness increased with age in both se xes. No differences were found between the left- and right-hand side. For each age group (and corrected for stature and weight), males had s ignificantly thicker masseters than females (p < 0.01). Variation in m uscle size and facial dimensions mainly coincided with variation in ag e, stature and weight. Apart from these, muscle thickness showed a sig nificantly negative relation with anterior facial height and mandibula r length, and a significantly positive relation with intergonial width and bizygomatic facial width. Copyright (C) 1996 Elsevier Science Ltd .