Three-dimensional courses of zygomaticofacial and zygomaticotemporal canals using Micro-CT in Korean
Micro-CT를 이용한 한국인의 광대얼굴관과 광대관자관 유형의 3차원분석
Dept. of Dentistry/박사
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 zygomatico-orbital (ZO) foramen and enter their own bony canals within the zygomatic bone. Alternatively, the zygomatic nerve itself may enter the bone before dividing. However, multiple zygomaticofacial and zygomaticotemporal canals (ZFC and ZTC, respectively) can be observed, and their detailed intrabony courses are unknown. Clinically, the zygomatic region is an area where many surgical procedures are performed and a region that is vulnerable to maxillofacial trauma. Generally, the foramina on the surface of the zygomatic bone are used as landmarks to avoid damaging the nerves and vessels running inside the zygomatic bone when osteotomy is carried out. Therefore, we performed this study to 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 zygomatic bones were prepared from 7 Korean cadavers (3 males and 4 females with a mean age of 80.8 years). 2D images of all the specimens were scanned micro-CT scanner (1076, SkyScan, Antwerp, Belgium), and the demarcated canal structures of each ZFC and ZTC were three-dimensionally reconstructed using computer software (Mimics, Version 10.01, Materialise, USA). Then, the ZFCs and ZTCs were extracted from the three-dimensional images and classified according to their entry and exit patterns and corresponding foramina.The ZF, ZT, and ZO foramina were observed in every instance, seen on the facial surface (as 1 foramen (3 cases), 2 foramina (5 cases), 3 foramina (5 cases), and 4 foramina (1 case)); on the temporal surface (as 1 foramen (7 cases), 2 foramina (4 cases), 3 foramina (1 case), and 4 foramina (2 cases)); and on the orbital surface (as 1 foramen (1 case), 2 foramina (2 cases), 3 foramina (5 cases), 4 foramina (5 cases), and 5 foramina (1 case)) of the zygomatic bone, respectively. However, the number of ZO foramina at the orbit was not coincident with the exit of the ZF foramen (or foramina) and ZT foramen (or foramina) at the facial surface. In only 4 of the specimens (28.5%) did each single ZFC (2~3) and ZTC (2~3) open at the ZO foramen (or foramina) independently through each of the corresponding zygomaticotemporal (2~3) and zygomaticofacial foramina (2~3), respectively. In contrast, the ZTC(s) originated from the ZFC(s) in 10 of the specimens (71%). Among these 10 specimens, there were cases in which no entry of the ZTC was seen (5 cases) and cases in which the entry of the ZTC(s) was observed within the lateral wall of the orbit (5 cases).