Orbital fractures usually happen when an object or fist hits the eye. In an orbital blowout fracture, bones inside the eye socket shatter. The muscles that support the eyes can stretch, tear or become trapped. Children are especially susceptible to this.

The orbit, or eye socket, is actually composed of seven facial bones: the frontal, zygomatic, lacrimal, maxillary, ethmoid, palatine, and sphenoid bones.  It contains not only the eyeball (orbit), optic nerve (nerve responsible for vision), and extraocular muscles (muscles that move the eye), but also nerves that provide eye and eyelid motion and sensation to the forehead and face. The orbit is divided into the orbital roof (top of the orbit), medial orbital wall (inner orbit adjacent to the nose), lateral orbital wall (outer wall of the orbit), and orbital floor (bottom of the orbit). 

Diplopia (double vision) is common after fractures of the orbital floor and medial orbital wall. They can become injured with orbital fractures limiting the motion of the eye and causing double vision.