Orbital floor fractures: a reassessment of pathogenesis.

Historically, blow-out fractures were ascribed to backward displacement of the eyeball which increased the intraorbital pressure causing the floor to fracture. By using dry skull and cadaver specimens, we have shown that minimal trauma to the orbital rim produces a segmented fracture of the orbital floor without the presence of the eyeball. It appears, however, that the pressure from the bulb is necessary to produce a depressed fracture of the orbital floor.