The zygomatic nerve (ZN), which originates from the maxillary nerve at the pterygopalatine fossa, enters the orbit through the inferior orbital fissure. Within the lateral region of the orbit, the ZN divides into the zygomaticofacial (ZF) and zygomaticotemporal (ZT) nerves. The ZF and ZT nerves then pass on to the face and temporal region through the zygomaticoorbital foramen and enter their own bony canals within the zygomatic bone. However, multiple zygomaticofacial and zygomaticotemporal canals (ZFCs and ZTCs, respectively) can be observed, and their detailed intrabony courses are unknown. The aim of this study was clarify the three-dimensional intrabony courses and running patterns of the ZFCs and ZTCs, both to obtain a detailed anatomical description and for clinical purposes. Fourteen sides of the zygomatic bones were scanned as two-dimensional images using a micro-computed tomography (CT), with 32-μm slice thickness. Intrabony structures of each canals were three-dimensionally reconstructed and analyzed using Mimics computer software (Version 10.01; Materialise, Leuven, Belgium). We found that some ZTC was originated from ZFC. In 71.4% of the specimens, the ZTC(s) divided from the intrabony canal along the course of the ZFC(s). In other cases, 28.6% of ZTCs were opened through each corresponding ZT foramen. Zygomaticofacial canal originates from zygomaticoorbital foramen, divided into some of ZTCs, and is finally opened as ZF foramen. This new anatomical description of the intrabony structures of the ZFC(s) and ZTC(s) within the zygomatic bone by micro-CT technology provided helpful information to surgeons performing clinical procedures such as Le Fort osteotomy and reconstructive surgeries in the midface region.

The purpose of the present study was to provide precise data regarding the branching pattern of the submental artery, which should be considered in occasions of bleeding during various dentoalveolar surgical procedures of the mandible, such as implant surgeries, tori removal, and iatrogenic injuries. Twenty-six embalmed adult hemifaces from Korean cadavers were used in this study. The vertical distance, horizontal distance, and diameter of the submental artery were measured from the site of the first premolar to the third molar. In cases where there was penetration of the mylohyoid muscle by the main branches of the submental artery, the same items were measured at that point. The vertical distance between the submental artery and the inferior border of the mandible decreased toward the premolar, whereas the horizontal distance from the lingual plate of the mandible increased gradually as it traveled in the anterior direction. The diameter of the artery narrowed slightly toward the premolar. The main branches of the submental artery perforated the mylohyoid muscle in 14 (54%) of the 26 specimens. As a result of this study, the submental artery is located higher from the inferior border and closer to the lingual plate of the mandible in the region of the molar than that of the premolar. Therefore, clinicians should be more careful of bleeding when performing surgery in the molar region compared with the premolar region. Where the mylohyoid muscle is perforated by the main branches of the submental artery, its point of insertion can be observed in diverse locations.