A blow to the side of a patient’s face drives his zygoma inwards, usually on one side only. The zygomatic bones are so closely united to the frontal and temporal bones, that, when they fracture, the neighbouring parts of these other bones usually do so too. The zygomatic complex therefore usually fractures as a whole. The displaced zygomatic fragment can rotate clockwise, or anticlockwise, and its orbital rim can be inverted or everted. The floor of the orbit is always partly comminuted.
If you see a patient early enough, you may see that the side of his face is flattened. Oedema fills out this flattening within three hours, and it does not return for a week, after the oedema has subsided. If you are in doubt, there is a useful test for flattening of the zygoma. Put two pencils on either side of his face. They should lie parallel to one another. If the lower end of a pencil is tilted inwards, the patient’s zygoma is flattened on that side, as in Fig. 62-12. The obviousness of this flattening depends greatly on whether he has a thin bony, face which accentuates the displacement, or a fat one, which hides it.
When a patient’s zygoma is injured, his maxillary sinus fills with blood, so that his nose bleeds from that side. Injury to his infra–orbital nerve makes his cheek numb, and displacement of the lower part of his orbit pushes his eye downwards, and restricts its movements. Herniation of the fat in his orbit into his maxillary sinus may also make his eye sink inwards and downwards, and cause diplopia. This can also be caused by injuries of his 6th nerve, or his ocular muscles or their attachments. It can be temporary or permanent. If it is due to a fracture of his zygomatic complex, reducing this may correct it.
Sometimes, only the arch of a patient’s zygoma is fractured. There is a depression over it, and the movement of the coronoid process of his mandible is restricted. Although the depression maybe obvious at the time of the injury, it may rapidly fill with oedema and become invisible. If his mouth was open when he was injured, he may be unable to close his jaw. Don’t try to elevate the fragment, unless he has difficulty moving his jaw.
Fragments of the zygomatic arch are held by the zygomatic fascia, and although they may displace inwards, they don’t move in other directions. The patient’s temporalis fascia is attached to the superior border of his zygomatic arch, whereas his temporalis muscle is attached to his coronoid process. This enables you to pass an elevator between the fascia and the muscle, and lever his zygomatic arch outwards into place. Try to operate within the first 48 hours, when the replaced fragment is more likely to be stable and less likely to need wiring. After two weeks, the ends of the fragments will have softened and rounded, and you will probably need to wire them, after 4 weeks they will have united so that you cannot move them. After this length of time they will probably need open refracture, open reduction, and wiring.
The methods below do not include packing the maxillary sinus, and repairing the orbital floor. If the contents of a patient’s orbit have prolapsed into his maxillary sinus, and you cannot refer him, he will have to live with his enophthalmos and wear an eye patch.