WHEN the eye is struck by a nonpenetratinghydraulic forces generated are often sufficient to cause fracture of the thin orbital floor with herniation of the orbital contents into the maxillary sinus. This frequently occurs without fracture of the orbital rim. The thin posterior two thirds of the orbital floor which is further weakened by the passage of the infraorbital nerve and artery is the area of predilection for fracture (Fig 1). Edema and hemorrhage may compensate for the displaced tissue, and it may be only after the acute phase has subsided that the injury becomes apparent by enophthalmos and limitation of eye movement. By this time repair becomes difficult with complete correction often impossible. Consequently, every physician treating injuries of the face and eye, even the common black eye, should be aware of this problem. The prime disability that may occur as a result of the injury is to the