Supraorbital notches and foramen in adult human skulls in south india-a morphological and morphometric analysis

Background: The supraorbital nerve is one of the main cutaneous nerves supplying the forehead and scalp region. It exits through the supra-orbital foramen/notch to innervate the skin and may be injured during various surgical and anesthetic procedures. The exact location, morphology and morphometry of these foramen show variations which had great clinical impact. This study focuses on such variations. Materials and methods: The study is done in 106 human dry crania from the department of Anatomy, Yenepoya Medical College. Eight different bilateral combination patterns of the notches/foramen are determined and percentage of incidence calculated. The distance of the foramen/notch from 2 reference points namely, the nasion and fronto-zygomatic suture is calculated andthe dimensions of the foraminaor notch is measured using vernier calipers and the mean value as well as range is analysed. The number of accessory foramen/notches are determined bilaterally and their relation to the main SOF/SON is established. Results: The most common pattern is determined to be bilateral notches with 41.51% incidence. The mean distance of the SOF/SON from nasion was23.65mm on right side and24.17mm on left side and from fronto-zygomatic suture was 27.83mm on right side and 28.41mm on left side. The mean horizontal length of the notch was 3.76mm on right side and 3.66mm on left side and that of SOF was 2.96mm on right side and 3.27mm on left side. The vertical length of SOF was calculated to be 1.55mm on right side and 1.61mm on left side. The number of accessory foramen were found to be more on right side and accessory notches more on left side. These accessory openings are found to be more associated with the main notch than the foramen. Conclusion: There is a difference in the position and dimensions of SOF /SON and thorough anatomical knowledge of SON /SOF is important in various procedures in surgery and anesthesia.