Procedures :: Surgical
at the medial point between the lateral angle and the root of the helix. It is at this location, deeply towards the nerve, that the layer of superficial temporal fascia is found, separating the zygomatic nerve. In fact the nerve is divided into numerous branches above the zygomatic arch and is more secure, presumably because the nerve occupies an area with a width of approximately 2cm of the arch and approximately 2cm of the lateral orbital rim. Furthermore, the markings of the temporal frontal branch are 1,5cm above the lateral segment of the eyebrow and 2cm laterally to the lateral orbital rim. It may also be found in relation to the sentinel vein (the largest vein seen during an endoscopic lift, between the temporoparietal fascia and the deep temporal fascia) (Figure 17.2).
The supraorbital and supratrochlear nerves are the sensory nerves of the eyebrow (Figure 17.3). The supraorbital nerve exits the supraorbital arch through a fissure or foramen to the medial canthus, really high at 1cm above the supraorbital rim3. Studies performed on cadavers have demonstrated that the supraorbital nerve is divided into medial (superficial) and lateral (deep) branches. The superficial division is subdivided into various branches that penetrate the frontalis muscle and continue in a cephalic direction, on top of the frontalis muscle.
to supply 3,5cm of the frontal part of the scalp. The deep division runs laterally, between the galea and the periosteum, and continues until the coronal suture. The supratrochlear nerve exits immediately laterally to the corrugator at the medial supraorbital rim, before entering the corrugator and, thereafter, divides into various smaller branches, which, then, follow their trajectory on top of or immediately below the surface of the corrugator muscle. Afterwards, these branches penetrate the frontalis muscle and run along its ipsilateral medial surface towards the scalp.
Figure 17.2 Drawing indicating the superficial anatomical relationship between the sentinel vein and the temporal branch of the facial nerve. The danger zone has a diameter of 10mm and is marked out where the two lines intersect: one is extended from the Mentonian Foramen until the lateral orbital rim and the other from the superior orbital rim to the where it crosses the inner ear with the zygomatic arch.
Figure 17.3 Branches of the supratrochlear nerve penetrating through the corrugator muscle. The orbicular muscle of the eye was reflected downwards, and the incision of the periosteum performed from above.