Abstract
It has been mentioned by many clinical observations that the fractures of the mandible caused by dull forces were frequently occured at the mental, angle and condyle regions, and rarely at the regions of the ascending ramus and coronoid process. It is also clinically observed that, though the fractures at the horizontal ramus is usually expressed as that at the alveolar region, the directions of the fracture lines are not always parallel with the axis of the teeth and that most of them run obliquely forward or backward to the axis.
The regions and directions of mandibular fractures are examined by the X-ray pictures of 169 mandibular fractures caused by trauma. On the other hand, the strain on the surfaces by the external forces acted upon the dried human mandible hold by the both condyles is measured both quantitatively and qualitatively . The results of them are compared to study the relationship between them.
