"Blow-in" fracture of the orbit

A blow-out fracture is a relatively common injury in which the orbital floor and its contents are displaced downward toward the maxillary sinus. The reverse blow-out fracture has been identified as a "blow-in" fracture. It is a rare injury in which the fractured floor of the orbit is elevated into the orbit. The second known case of a "blow-in" fracture is reported and a mechanism of injury suggested. The fracture should be looked for in trauma cases in which the anterior wall of the maxillary sinus is depressed. Treatment of this unusual fracture is outlined in a case report.