Frontal branch of the facial nerve: Galeal temporal relationship

Abstract

Risks to the frontal branch of the facial nerve, especially at the juncture of the zygomatic arch, have been well studied in connection with aesthetic procedures. The use of bicoronal incisions led to the observation that there is a second area in which injury to the frontal branch of the facial nerve is at risk: the transition plane between the area over the temporalis muscle and the pericranial region. A study was conducted to map out the frontal branch of the facial nerve as it passes through the dense galeal temporal fascia, because this is a zone of potential injury. Ten fresh frozen cadaver halves were dissected by use of a standard surgical bicoronal approach with surgical instrumentation and loupe magnification x 2.5. In the area of interest, which included the region overlying the zygomatic arch, as well as the galeal frontalis fusion point, the nerve was found to be deep and within the fusion point. The nerve was cephalad to the sentinel vein in each instance, and the tissue was freely dissected medial and lateral to the fusion point of the galea and the temporal fascia. The fusion plane was dense and in a direct line in the vertical direction with the loose areolar plane on either side. The dense tissue within the galeal temporal region needs to be approached with caution, avoiding electrocautery and using sharp dissection. The cadaver study demonstrates the close proximity of the nerve in the deeper portion of the elevated superficial flap.