Blow-out fractures of the orbit

'Blow-out' fractures of the orbit are usually produced by direct trauma to the upper face. The eye itself is rarely ruptured but the thin orbital floor is often fractured and the eye and its surrounding fat are pushed into the roof of the maxillary sinus – the depressed fracture of the orbital floor can be seen as the 'teardrop sign' on X-ray (a). The inferior rectus muscle can be trapped in the fracture preventing upward gaze (b) causing double vision (diplopia) on looking upward.