orbital blow-out fracture

A dramatic eye injury in which the globe of the eye is forced posteriorly, fracturing the floor of the orbit and trapping the inferior rectus muscle (one of the oculomotor muscles that move the eye). Classically, the rim of the orbit remains intact so that the fracture is not palpable. A blow-out fracture is indicated by the eye appearing abnormally sunken (enophthalmus), double vision (diplopia), and, if the infraorbital nerve is trapped, lack of feeling underneath the eye. Typically, a blow-out fracture is caused by a knee, elbow, or fist hitting the eye during a contact or collision sport.