Pathogenesis and x-ray diagnostics of lateral fractures of the middle third of the facial skeleton.

Abstract

The comparison of statistics reveals an in­ crease of the number of fractures of the middle third of the facial skeleton in the last decade. In the past the unilateral fractures of the middle third of the facial skeleton were usually looked upon as individual ones only, e. g. as fractures of the upper jaw, zygoma, zygomatic arch or orbit. These isolate and mostly incom­ plete diagnoses were made due to the lack of knowledge of the fracture mechanism and of unsuitable x-ray projections or an ins ufficien t evaluation of the x-ray films. The architecture of the middle th ird of the facial skeleton is adapted to the transfer of the vertical chewing pressure. However, if a sagit­ tal or lateral force is directed against the lateral facial skeleton various types of fractures are caused according to the area of impact and the resistence of the underlying tissues. The prominent body of the zygoma is firm and resistant to impacts, the force of which it transfers to the th in walls of the maxillary sinus, the orbit and the zygomatic arch . Owing to the minimal flexibility of the cortical pillars of the body of the zygoma the zygomatico­ maxillary complex most frequently fractures as a whole. If a violent force, limited to a small area, acts against the zygomatic process of the maxilla it brings about a zygomatico-maxillary fracture with the splitting of the facial wall of the maxillary sinus, frequently associated with a fracture of a greater portion of the lower part of the orbit. At another instance a blunt force, directed on the globe, may produce a sudden increase of the intra-orbital pressure and a retromarginal fracture of the orbital floor. If a lateral impact hits only the zygomatic arch an isolated impression fracture will usually