The zygomatic arch is the slender bony bridge between the face and the temporal region, formed by the zygomatic process of the temporal bone posteriorly and the temporal process of the zygomatic bone anteriorly, united at the zygomaticotemporal suture. The masseter muscle originates from the inferior border and medial surface of the arch, and the temporalis muscle belly passes deep to the arch during its descent to the coronoid process.
The zygomatic arch is fractured as an isolated injury or as part of zygomatic complex fractures (ZMC), typically from direct lateral facial impact. Isolated arch fractures produce a characteristic palpable step deformity and trismus from impingement of the fractured fragment against the coronoid process of the mandible. Reduction is achieved via the Gillies approach, introducing an instrument through a temporal incision deep to the temporalis fascia to lever the fragment outward. In orbital and temporal access surgery, the zygomatic arch is reflected with the temporalis muscle in the zygoma-extended middle fossa approach.
A direct blow to the cheek fractures the arch in an inverted V-pattern, producing cosmetic asymmetry and trismus from coronoid impingement; reduced via a Gillies temporal approach by inserting a periosteal elevator deep to the temporalis fascia and levering the fragment laterally, usually requiring no fixation once reduced.
High-energy facial trauma produces a zygomatic complex fracture at all four sutures including the arch, requiring open reduction and fixation at multiple sites to restore the lateral facial skeleton, orbital volume, and cheek projection.
