Incidence and morphological study of zygomaticofacial and zygomatico-orbital foramina in dry adult human skulls: the non-metrical variants.

Morphological diversity in the form of multiple zygomaticofacial (ZF) foramina was studied in 165 dry, unsexed adult human skulls. Zygomatic bones revealed variation in the number of foramina on their orbital and facial aspects. These were absent in 72 (21.8%) sides. A single ZF foramen was seen in 148 (44.9%) sides. Two ZF foramina were found in 92 (27.9%) sides, out of which 29 (8.8%) sides had one zygomatico-orbital (ZO) foramen, while 63 (19.1%) sides had two ZO foramina. Three ZF foramina, a relatively uncommon occurrence, were found in 17 (5.1%) sides, which included eight (2.4%) sides with one less and nine (2.7%) sides with the same number of ZO foramina. Four ZF foramina were seen in one (0.3%) side with three on the orbital aspect, a feature not reported before. The zygomatic nerve may be disrupted on elevating periorbita from the lateral wall during orbital surgery, and care should be taken to prevent injury to the nerve during the lateral orbitotomy approach to access intraorbital soft tissue tumors.