The zygomaticomaxillary complex fracture, also known as a quadripod fracture, quadramalar fracture, and formerly referred to as a tripod fracture or trimalar fracture, has four components, three of which are directly related to connections between the zygoma and the face, and the fourth being the orbital floor. Its specific locations are the lateral orbital wall (at its superior junction with the zygomaticofrontal suture or its inferior junction with the zygomaticosphenoid suture at the sphenoid greater wing, separation of the maxilla and zygoma at the anterior maxilla (near the zygomaticomaxillary suture), the

zygomatic arch In anatomy, the zygomatic arch, or cheek bone, is a part of the skull formed by the zygomatic process of the temporal bone (a bone extending forward from the side of the skull, over the opening of the ear) and the temporal process of the zygo ...

, and the orbital floor near the

infraorbital canal The infraorbital canal is a canal found at the base of the orbit that opens on to the maxilla. It is continuous with the infraorbital groove and opens onto the maxilla at the infraorbital foramen. The infraorbital nerve and infraorbital arte ...

Signs and symptoms

On physical exam, the fracture appears as a loss of cheek projection with increased width of the face. In most cases, there is loss of sensation in the cheek and upper lip due to infraorbital nerve injury. Facial bruising, periorbital ecchymosis, soft tissue gas, swelling,

trismus Trismus, commonly called ''lockjaw'' as associated with tetanus, is a condition of limited jaw mobility. It may be caused by spasm of the muscles of mastication or a variety of other causes. Temporary trismus occurs much more frequently than perma ...

, altered mastication,

diplopia Diplopia is the simultaneous perception of two images of a single object that may be displaced horizontally or vertically in relation to each other. Also called double vision, it is a loss of visual focus under regular conditions, and is often v ...

, and

ophthalmoplegia Ophthalmoparesis refers to weakness (-paresis) or paralysis (-plegia) of one or more extraocular muscles which are responsible for eye movements. It is a physical finding in certain neurologic, ophthalmologic, and endocrine disease. Internal ...

are other indirect features of the injury. The zygomatic arch usually fractures at its weakest point, 1.5 cm behind the zygomaticotemporal suture.

Cause

The cause is usually a direct blow to the malar eminence of the cheek during assault. The paired

zygoma The term zygoma generally refers to the zygomatic bone, a bone of the human skull commonly referred to as the cheekbone or malar bone, but it may also refer to: * The zygomatic arch, a structure in the human skull formed primarily by parts of the ...

s each have two attachments to the cranium, and two attachments to the

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...

, making up the orbital floors and lateral walls. These complexes are referred to as the zygomaticomaxillary complex. The upper and transverse maxillary bone has the zygomaticomaxillary and zygomaticotemporal sutures, while the lateral and vertical maxillary bone has the zygomaticomaxillary and frontozygomatic sutures. The formerly used 'tripod fracture' refers to these buttresses, but did not also incorporate the posterior relationship of the zygoma to the sphenoid bone at the zygomaticosphenoid suture. There is an association of ZMC fractures with naso-orbito-ethmoidal fractures (NOE) on the same side as the injury. Concomitant NOE fractures predict a higher incidence of post operative deformity.

Treatment

Non-displaced or minimally displaced fractures may be treated conservatively. Open reduction and internal fixation is reserved for cases that are severely angulated or comminuted. The purpose of fixation is to restore the normal appearance of the face. Specific attention is given to the position of the malar eminence and reduction of orbital volume by realigning the zygoma and sphenoid. Failure to correct can result in rotational deformity and increase the volume of the orbit, causing the eye to sink inwards. Fractures with displacement require surgery consisting of fracture reduction with miniplates, microplates and screws. Gillie's approach is used for depressed zygomatic fractures. The prognosis of tripod fractures is generally good. In some cases there may be persistent post-surgical facial asymmetry, which can require further treatment.

References

External links

{{Fractures Oral and maxillofacial surgery Bone fractures