MORPHOMETRIC ANALYSIS OF THE INFRAORBITAL FORAMEN IN RELATION TO FACIAL LANDMARKS IN ADULT NIGERIAN SKULLS

ABSTRACT

The infraorbital foramen is an important anatomical landmark on the maxilla that transmits the infraorbital neurovascular bundle and is routinely used for regional anesthesia and midfacial surgical procedures. Because its position, size, shape, and number may vary between individuals and populations, accurate morphometric data are essential for safe clinical practice. This study aimed to document the morphometric characteristics, shape variations, and occurrence of accessory infraorbital foramina in adult Nigerian skulls and to assess side and sex differences. A cross-sectional descriptive study was conducted on 100 dry adult human skulls (200 sides) obtained from anatomy departments in southern Nigeria. Linear measurements from the infraorbital foramen to selected facial landmarks were obtained using a digital Vernier caliper, and morphological features were recorded. Data were analyzed using descriptive statistics, paired sample t-tests for side comparison, and independent sample t-tests for sex differences, with significance set at p < 0.05. The infraorbital foramen was located approximately 28.5 mm from the facial midline and 7–8 mm inferior to the infraorbital margin. Bilateral symmetry was generally observed, although a small but significant right–left difference was noted for the infraorbital foramen–infraorbital margin distance. Males showed significantly larger infraorbital foramen–midline and infraorbital foramen–margin distances than females. Morphologically, the oval shape was predominant (69%), followed by round (30.5%) and rare semilunar forms (0.5%). Accessory infraorbital foramina were uncommon, occurring in 3% of sides, with rare bilateral presentation confined to males. These findings highlight sex- and side-related variations in infraorbital foramen anatomy and provide population-specific reference data relevant for anesthesia, maxillofacial surgery, and forensic applications in Nigeria

Key words: Infraorbital foramen; Morphometry; Foramen shape variations; Nigerian skulls