Study of anatomical variations of the zygomaticofacial foramen and calculation of reliable reference points for operation.

Dissection on to the facial aspect of the zygoma is common in procedures of the midface for trauma, craniofacial deformity, and cosmesis. These procedures carry the risk of injury to the neurovascular structures that exit from the zygomaticofacial foramen (ZFF). The purpose of this study was to map the ZFF, and to establish reliable reference points from which to identify it before and during operation. We also aimed to compare the anatomy of the ZFF between sexes and among geographical populations. A total of 429 adult skulls from nine geographical sites were used. A cross-line laser was superimposed on to each zygoma to generate consistent landmarks (lines 1 and 2) from which to measure the ZFF, and the number of ZFF on each zygoma was recorded. The site and incidence of ZFF differed significantly among geographical populations, but not between sexes. Of all 858 sides, no foramina were found in 16.3%, one foramen in 49.8%, two foramina in 29%, three in 3.4% and four in 1.4%. A total of 93% of foramina were within a 25mm diameter zone (ZFF zone) centred 5mm anterior to the intersection of lines 1 and 2 on the right zygoma, and 94% were within equivalent measurements on the left. Using these landmarks, we propose a new method of identifying a ZFF zone that is irrespective of sex or geographical population. This technique may be useful in the prevention of iatrogenic damage to the ZFF neurovascular bundle during procedures on the midface and in local nerve blocks.