Blunt trauma to the eye and bones around the eye (such as by a fist) can lead to a fracture in the thin bones of the orbit behind the eye. Anyone with such injury should seek out a complete eye examination to rule out any other eye injury promptly. The floor and inside wall of the orbit are especially thin, and sinuses are on the other side of the bone. Blunt trauma can cause what is termed a "blow-out fracture", where the sudden rise in pressure in the orbit literally blows a fracture through the bone and into the sinus. If this involves the floor of the orbit, the cheek below the eye and upper gums in the mouth can often become numb due to damage to a sensory nerve that runs in the floor of the orbit.

If the fracture of large enough, the contents of the orbit can start to slip into the sinus, and the eye will appear to sink backwards. Sometimes an eye muscle can get trapped in an orbital fracture and become stuck. This leads to double vision especially if looking up, with pain. A CT scan of the orbit can diagnose fractures and entrapment of muscles. Entrapped muscles often have to be released surgically. Antibiotics are usually given after an orbital fracture, due to risk of infection from the sinus into the orbit.