Variations of the Frontal Exit of the Supraorbital Nerve: An Anatomic Study

Abstract

Until now, it has been taken for granted that the point of emergence of the supraorbital nerve is by way of a notch or a foramen at the border of the inner to the medial third of the supraorbital rim. In contrast to several anatomic textbooks, we noticed that the exit point was repeatedly not at the site where anticipated when implanting lid springs for facial palsy. This gave us the idea of investigating these variations and how big they are, because most open and recent endoscopic forehead lift techniques have relied on a constant exit point of the supraorbital nerve. A total of 507 macerated skulls (1014 orbits) from three anatomic collections in Austria and Germany were studied. All skulls were adult European skulls gathered from the prehistoric age up to the twentieth century. Additionally, 18 fixed cadavers (36 orbits) and 25 fresh cadavers (50 orbits) were studied. These data were not included in the statistical analysis but in the discussion. The anatomic measurements on the skulls were carried out with an anthropometric calliper. The examinations concentrated on the configuration (notch/foramen) and the number of exit point(s) on the supraorbital rim, the vertical distance from the supraorbital rim, and the distance from the nasion to the various exit point(s). Combining all of these parameters, 74 percent of the skulls showed asymmetric findings between the right and left orbits. In 15 percent of both orbits, the supraorbital nerve left the orbital cavity already in its two branches, the medial and lateral branch, either through a notch or a foramen, the foramen being sometimes the exit of a supraorbital canal. The average distance from the nasion to the frontal notch/foramen was 25 mm on both orbits (range 16 to 55 mm) and to the supraorbital notch/foramen 31 mm (range 20 to 49 mm). The largest vertical distance from the supraorbital rim to its farthest exit point was 19 mm. Other than what is cited in literature, the variations concerning the configuration and the distance of the exit point(s) of the supraorbital nerve were so significant that all forehead operations, especially those using endoscopic techniques, must take into account these findings.

Localization of important facial foramina encountered in maxillo‐facial surgery

“…In the present study, these measurements would localize the SOF/SON on either side (65 mm). The mean distance of the supraorbital passage from the midline in various studies ranges from 22 mm to 31 mm (Chung et al, 1995;Beer et al, 1998;Cutright et al, 2003;Saylam et al, 2003;Cheng et al, 2006). In most studies, the supraorbital was 20 mm to 30 mm from the midline (Erdogmus and Govsa, 2007;Cheng et al, 2006) and this is similar to our findings.…”

“…Knowledge of the location of these nerves is also necessary during various endoscopic procedures, which are increasingly being used for cosmetic facial surgery (Cutright et al, 2003;Saylam et al, 2003). Excessive dissection and retraction close to such neurovascular bundles can cause scarring, which may lead to entrapment neuropathies and painful neuralgias (Caputi and Firetto, 1997;Beer et al, 1998). A large variety of maxillofacial surgical procedures require incisions on the face and reflection of musculo-cutaneous flaps for exposure of the frontal, peri-orbital, and mandibular regions.…”

Localization and morphometric evaluation of Supraorbital and Infraorbital foramen in Dravidian Population of Southern India: A paleoantropological study on dry skulls.

“…Saylam et al 2003 stated that the frequency of absence of SOF/N was in 5.5% on right and 10% on left side of skull [12]. Beer et al 1998 showed 3% absence in European skull [13]. But in this study there was no absence of notch / foramen.…”

Course of the Bony Canal Associated with High-Positioned Supraorbital Foramina: An Anatomic Study to Facilitate Safe Mobilization of the Supraorbital Nerve

“…The lateral branch ascends between the galea aponeurotica and the pericranium to innervate a narrow area of the parietal scalp [1 -3] . The confi guration of the bony exits of the SON in the supraorbital region has been classifi ed into 7 types as single-notch (most frequent), single foramen (second-most frequent), lateral foramen and medial notch, double foramina, double notches, no apparent notch or foramen, and lateral notch and medial foramen types [4] . Exits located in the lateral region of the orbit are designated supraorbital notch or foramen; exits in the medial region are called frontal (or supratroof Anatomy and Neurosurgery.…”

“…Exits located in the lateral region of the orbit are designated supraorbital notch or foramen; exits in the medial region are called frontal (or supratroof Anatomy and Neurosurgery. The characteristics of the bony exit of the SON were classifi ed into 7 previously reported types as single-notch, double-notch, single-foramen, double-foramina, lateral foramen and medial notch, lateral notch and medial foramen, and no apparent notch or foramen types [4] ( ᭹ ᭤ Fig. 1 ).…”