The incidence of condylar fracture is very high and most are not caused by direct trauma. On the other hand, fracture of the coronoid process is reported less often than fracture of other parts of the mandible. We report a case of right subcondylar and coronoid fractures without any evidence of direct trauma to the zygomatic area or an indirect trauma to the mandibular corpus or sypmheseal region. The possible cause was identified as acute reflex contraction of the temporalis muscles leading to coronoid and condylar stress fractures.