Orbital "blow-in" fractures: clinical and CT features.

During a 16 month period, seven patients were admitted to our trauma center with "blow-in" fractures of the orbital roof. This injury results from a significant direct blunt force applied to the supraorbital region of the frontal bone with transmission of energy to the thin orbital plate of this bone and displacement of bone fragments downward into the superior orbit. High resolution CT with multiplanar reformation and three-dimensional display proved very useful in identifying and characterizing the bone and soft tissue abnormalities found in our patients. Our experience suggests that CT demonstration of supraorbital frontal bone fractures and/or frontal lobe cerebral contusions is an indication for thin section CT of the entire orbit, even when there is no evidence of a superior orbital rim fracture. Demonstration of an orbital blow-in fracture should prompt careful clinical assessment of the globe, optic nerve, and extraocular muscles to identify and appropriately manage underlying injuries to these structures.