Morphometric Analysis of the Supraorbital Foramen in the South African Population

Abstract

The supraorbital notch (SON) or supraorbital foramen (SOF) is located at the level of the supraorbital rim, housing the supraorbital neurovascular bundle which supplies the scalp, forehead, skin and muscles of the upper eyelid. In this study, 108 dry skulls were examined, to determine these morphometric data: width of SON/SOF and position of SON/SOF relative to the nasal midline and frontozygomatic suture. Left and right sides were compared and differences between the sexes were considered. In a South African population, SON (44%) was the most commonly identified passageway, followed by the SOF (27%), absent SON/SOF (19%), double foramen (5%), co-occurrence (4%), and double notch (1%) respectively. This study localised the SON/SOF approximately 26.87 mm ± 4.21 from the nasal midline to SON/SOF in females, and 28.20 mm ± 3.68 in males. When using the frontozygomatic suture as a reference point, SON/SOF lies 28.42 mm ± 3.00 medially in females and 29.83 mm ± 2.80 in males. The positional distances were significantly greater in males than females. No significant differences were observed between the left and right side. The width of SON was approximately 4.16 mm ± 1.81, and diameter of SOF was approximately 2.60 mm ± 1.14. The findings of this study are relevant to surgeons when operating in the supraorbital region. Accurate anatomical knowledge of neurovascular architecture and foramina localisation can help avoid iatrogenic injury during administration of local anaesthetic, retraction of musculocutaneous scalp flaps or surgical dissection of the supraorbital region.