bilateral horizontal fracture of the maxilla , classified as Le Fort I, Le Fort II, or Le Fort III according to degree of severity, with Le Fort III fractures being the most serious, usually involving multiple fractures of facial bones. Le Fort I fracture a horizontal segmented fracture of the alveolar process of the maxilla, in which the teeth are usually contained in the detached portion of the bone; called also Guérin or horizontal maxillary fracture. Le Fort II fracture unilateral or bilateral fracture of the maxilla, in which the body of the maxilla is separated from the facial skeleton and the separated portion is pyramidal in shape; the fracture may extend through the body of the maxilla down the midline of the hard palate, through the floor of the orbit, and into the nasal cavity. Called also pyramidal fracture (of maxilla) . Le Fort III fracture a fracture in which the entire maxilla and one or more facial bones are completely separated from the craniofacial skeleton; such fractures are almost always accompanied by multiple fractures of the facial bones. Called also craniofacial disjunction and transverse facial fracture.