Blowout fractures are caused by direct trauma to the globe which causes an increase in intraorbital pressure and decompression via fracture of the orbital floor. Radiographically, fragments may be seen in the maxillary sinus or there may be opacification of the maxillary sinus with blood. Clinically, there may be diplopia on upward gaze due to entrapment of the inferior rectus muscle.
Waters' radiograph. This reveals herniation of fat into the left maxillary sinus, due to an orbital floor fracture.
