Orbital roof blow-out fractures.

The term blow-out fracture was co ined by Smith and Regan [1] to describe an orbital floor fracture caused by a very sudden increase in intraorbital pressure without concomitant fracture of the orbital rim . Most blow-out fractures involve the orbital floor. Less often the medial orbital wall is fractured either solely or in conjunction with a fracture of the floor [2]. Upward displacement fractures involving the orbital roof do occur but these accompany extensive craniofac ial fractures and usually invo lve the orbital rim . Thi s type of fracture does not share the hydraulic etiol ogy of true iso lated blow-out fractures . We describe two cases of isolated fractures of the orbital roof w ith intact orbital rims .