Answer:
Generally, mandibular fractures occur in weak areas, such as the subcondylar area, the angle region of the mandible that is weakened by the presence of the bone structure, the third molar tooth, and the cuspid region, where the long root of the cuspid tooth and the mental foramen weaken the parasymphysis. In the edentulous patient, most fractures occur between the body and the angle, an area that is weak through substantial loss of alveolar bone. The subcondylar fracture is frequently observed in both dentulous and edentulous mandible fractures because of its weak structure.
According to one review of 580 mandible fractures, location was as follows: condyle (29%), angle (25%), symphysis (22%), body (16%), alveolar (3%), ramus (1.7%) and coronoid (1.3%).
Muscles that elevate the mandible include the masseter, the medial pterygoid, and the temporalis. The protrusor muscles are the lateral pterygoids. The depressor retractor group of muscles includes the geniohyoid and digastric muscles. The mylohyoid muscle may result in lingual rotation of the mandible.
Favorable fractures are those in which the bevel of the fracture line results in a muscular force that pulls the fragments together. Horizontally favorable fractures are oriented downward and forward. Vertically favorable fractures are oriented from the lateral surface of the mandible, directed posterior and medial. This has little clinical significance.