Range of movement of mandible in children

The range of movement of the mandible was studied in 103 boys and girls aged 7 years, in 110 boys and girls aged 10 years, and in 60 women aged 20 years. The mobility of the mandible was estimated by repeated direct measurement of the maximal opening capacity, and in the 10‐year‐old children and the women also by measurement of maximal protrusion and lateral movement. The method for recording the mobility of the mandible proved to be precise. Lateral movement of the mandible to the right was greater than to the left both in children and adults. No difference in opening capacity or maximal protrusion was found between the boys and the girls, while lateral movement was somewhat larger in the boys. The mean maximal opening capacity was 46 mm in the 7‐year‐old children, 51 mm in the 10‐year‐old children, and 51 mm in the adult women. Maximal protrusion and lateral movement was, on the average, 9–10 mm in the 10‐year‐old children and in the adult women. The investigation suggests that in girls the range of movement of the mandible has reached adult level by 10 years. The opening capacity in children was found to be positively correlated with body height and body weight. Both in children and adults relatively high positive correlations were found between opening capacity, protrusion, and lateral movement.