A blowout fracture
is a fracture
of the walls or floor of the orbit
. Intraorbital material may be pushed out into one of the paranasal sinuses
. This is most commonly caused by blunt trauma of the head, generally personal altercations.
The term "blow out fracture" was coined in 1957 by Smith & Regan, who were investigating injuries to the orbit by placing a hurling ball on cadaverous
orbits and striking it with a mallet. The force of a blow to the orbit is dissipated by a fracture of the surrounding bone, usually the orbital floor and/or the medial orbital wall. Serious consequences of such injury include diplopia
on downward gaze if there is damage to the floor of the orbit.