Ultrasound and standard x-ray investigations before and after the reduction of the fractures were performed in 17 patients with zygomatic arch fractures. The ultrasound investigation of the bone surface is recommended as an additional diagnostic tool in the diagnosis and control of the reduction of zygomatic arch fractures. Intraoperative ultrasound imaging under sterile conditions is easy to apply and enables the surgeon to optimise therapeutic results. In 5 cases based on an intraoperative sonogram further reductions of zygomatic arch fractures were carried out. In another referred patient the diagnosis of a zygomatic arch fracture was excluded by ultrasound and confirmed by standard x-ray examinations.