Anatomic Variations of the Infraorbital Foramen in Caucasian Versus African American Skulls.

PURPOSE

The infraorbital foramen (IOF) represents a highly conserved structure but demonstrates morphologic variability. The purpose of this study is to describe the IOF location, size, and supernumerary foramina in an African American population and compare it with a Caucasian population.

METHODS

Sixty African American and 60 Caucasian skulls from the Hamann-Todd collection of the Cleveland Museum of Natural History were studied. The primary outcome was the number of accessory IOF and measurements of the location, size, shape, and direction of each foramen. Pearson chi-square, t tests, Fisher exact test, and Wilcoxon rank sum tests were used to analyze the data.

RESULTS

The African American population had a smaller vertical IOF diameter (mean = 2.81 mm) compared with the Caucasian population (mean = 3.08 mm) on the right side (p < 0.01). The distance from the IOF to the anterior nasal spine on the left side was greater in the African American population (mean = 33.93 mm) compared with the Caucasian population (Caucasian mean = 32.84 mm, p = 0.03). The distance from the IOF to the zygomaticomaxillary suture was significantly shorter in the African American population (mean = 11.85 mm) compared with the Caucasian population (mean = 13.21 mm) on the left side (p = 0.01). Accessory foramina were found in 13 Caucasian skulls (21.7%) and 6 African American skulls (10%; p = 0.08). Two distinct types of IOF existed in each population, one close to the main foramen and one within the sutura notha.

CONCLUSIONS

The IOF is smaller and exits more laterally, with a lower proportion of accessory foramina in an African American population compared with a Caucasian population. Both groups exhibit 2 distinct types of IOF. These morphologic differences should be noted during surgeries and anesthetic planning to avoid neurovascular complications.