1 C J Mieny, U Mennen: Principles of Surgical Patient Care - Volume ...

infraorbital nerve in the infraorbital canal. An isolated unilateral Le Fort II fracture with amidpalatal fracture may be seen occasionally.Arcus FractureThe arcus or temporal process of the zygomatic bone and zygomatic process of thetemporal bone may be involved without any fractures of the zygomatic bone itself. A fractureof the arcus, on its own, usually presents with three fractures of this bony arch and thefracture fragments will be displaced medially. A single fracture of the arcus is normally foundwhen it occurs in conjunction with a zygomatic bone of a Le Fort III fracture.Lateral or Supero-Lateral Orbital Margin FractureA direct blow against the supero-lateral margin of the orbita may result in thisrelatively rare type of fracture. The fracture may be simple or it may be comminuted.Inferior Orbital Blow-Out FractureAs in the case of a "medial orbital blow-out fracture" the inferior orbital blow-outfracture occurs after a direct blunt trauma force has been exerted against the globe. This isthe most common type of orbital blow-out fracture.The fracture involves the orbital floor or the roof of the maxillay sinus without anyinvolvement of the infra-orbital margin.The orbital floor may be cracked or comminuted, with or without displacement ofparts of the orbital contents into the maxillay sinus.Zygomatic Bone FractureThe zygomatic bone may be described as having "three feet" namely the frontalprocess, the temporal process and the malar process (adjacent to the maxillo-zygomaticsuture), hence the name "tripod", trimalar or malar-maxillary fracture. The zygomatic bonefracture is also known as the "quadrimalar" fracture, because it is possible to diagnose fourfractures surrounding the malar bone. These four fractures involve the following areas: thefronto-zygomatic suture, the temporo-zygomatic suture, the inferior region of the malarprocess, and the infra-orbital margin.A zygomatic bone fracture may be undisplaced, or displaced in the medial (mostly)direction. However, it may be displaced laterally, or rotationally in the antero-posterior orsupero-inferior dimension. The zygomatic bone may also be comminuted with bone fragmentsdislodged into the maxillary sinus. As in the Le Fort I and Le Fort II fractures, the maxillarysinus is always involved.Le Fort III FractureThis type of fracture is also known as a supra-zygomatic or a transverse facial fracture.The fracture line is in the region of the nasion and is usually one centimetre more superior24