Supraorbital notch and foramen: positional variation and relevance to direct brow lift.

PURPOSE: Forehead paresthesia after brow lift is well-documented with rates as high as 40.7%. The authors describe an anatomical study to identify the variation in position of the supraorbital notch/foramen to define safe limits for deep dissection during this procedure. METHODS: Sixty-six orbits from 23 dry skulls and 9 formalin-fixed cadavers were analyzed photographically using ImageJ software. The cadaveric specimens were dissected using a coronal incision, which allowed the inferior resection of the frontalis muscle and periosteum. The exit point of the supraorbital neurovascular bundle was noted as a foramen or notch. The position of the supraorbital notch or foramen was recorded in relation to the midline as defined by the sagittal suture at the level of the highest point of the supraorbital rim. The distance and angle for each foramen/notch were calculated. RESULTS: Thirty-three percent of orbits had a foramen. The average distance from the midpoint to the foramen was 25.24 mm (standard deviation 3.78 mm) and to the notch was 22.69 mm (22.69 mm). The range of distance between the midpoint and the foramen/notch was 17.62 to 32.35 mm. The average angle between the horizontal meridian and the foramen was 81/57° (standard deviation 4.69°). CONCLUSIONS: A wide variation in anatomy was seen. Greater caution is required when performing deep dissection around the supraorbital notch because of the variation in position of the supraorbital foramen.