Characterization and localization of the supraorbital and frontal exits of the supraorbital nerve in Chinese: an anatomic study.

PURPOSE

To elucidate the characteristics and location of the supraorbital and frontal exits of the supraorbital nerve in Chinese skulls and to compare these findings with other ethnic populations.

METHODS

The anatomy of the supraorbital nerve exits was studied in 97 adult Chinese skulls (194 orbits). The characteristics and location of the supraorbital nerve exits were determined. Analyses were performed to compare differences between sexes and sides. Data were then compared with those of the other populations.

RESULTS

Supraorbital exits were found in all 194 orbits. Among these, 89 (45.9%) were foramina. Frontal exits were found in 69 of the 194 (35.6%) orbits in which 18 were foramina (9.3%). The location of the supraorbital exits showed a skewed distribution toward the medial aspect of the superior orbital rim. The median distance between the supraorbital exits and the facial midline was 24.56 mm. Eighty percent of the supraorbital exits lay between 20.77 mm and 30.52 mm from the facial midline. The mean frontal exit was 7.02 mm medial to the supraorbital exits. Compared with other populations, a higher proportion of Chinese have foramina above the superior orbital rim as the exits for the supraorbital neurovascular bundle. The location of the supraorbital nerve exit is highly variable in all studied populations.

CONCLUSIONS

In a significant proportion of Chinese, the supraorbital nerve exits are located toward the medial aspect of and above the superior orbital rim. Extra care should be taken during dissection around this region to avoid damage to the supraorbital nerve.