forehead musculature. There is no natural plane between the intermediate temporal fascia and the deep temporal fascia into the zygomatic subperiosteal space. Because the dissection is subperiosteal, upper face and midface procedures superior to the zygomatic arch require a clear understanding of forehead anatomy, and careful dissection must be undertaken. The surgeon must dissect through the intermediate temporal fascia into the temporal fat pad space, then proceed into the zygomatic subperiosteal space.
The exact anatomy is complex and controversial in the temple area, probably because the layers are so thin and change over the zygoma. Dispute has been particularly contentious over what exactly happens between the temporal fat pad and the zygoma and whether this changes over the course of the zygoma from anterior to posterior.2-5 Aspects of anatomy that are well accepted include the following.The deep temporal fascia, which forms the floor for the temporal fat pad, is a discrete entity (Fig. 47-1). The intermediate temporal fascia forms the roof and is separate from (and deep to) the SMAS-superficial temporal fascia. The deep and intermediate temporal fascial layers coalesce on the zygoma. Most likely, the two leaflets of the temporal aponeurosis (deep temporal fascia and intermediate temporal fascia) fuse above
the zygoma, except in the central zygoma, where the fat pad inserts directly onto the zygoma,with no fusion of the layers. The frontal branch becomes more superficial as it heads posteriorly along the zygoma.6 Masseteric and zygomatic ligaments may hinder upward mobilization of midface layers (Fig. 47-2).
The midface has been defined as the region from the lower eyelid (or the zygomatic prominence) to the nasolabial fold and oral commissure. There has been a further subdivision of the midfacial region into the prezygomatic portion overlying the body of the zygoma and maxilla and the infrazygomatic portion covering the oral vestibule.7 Because the orbital septum, arcus marginalis, and inferior orbital rim are so integral to rejuvenation of the midface, they are probably best included with the midface.
The orbicularis retaining ligament above and the zygomatic-cutaneous ligament below define the prezygomatic space (Fig. 47-3). Below the zygomatic-cutaneous ligament courses the main motor branch to the orbicularis oculi muscle. In performance of any suborbicularis midface elevation, these ligaments are defeated to allow untethered upward rotation of the malar fat pad complex. Injury to the zygomaticofacial nerve and motor branches to the orbicularis oculi is avoided. During the downward dissection of a
FIGURE 47-1. Anatomy at temple-zygoma junction. The zygomatic anatomy is particularly important as it relates to endoscopic brow lifts. Note that the insertion of the temporal fascia varies according to the location on the zygoma. The deep temporal fascia and intermediate temporal fascia coalesce into the periosteum of the zygoma at the anterior and posterior thirds of the zygoma only. In the central zygoma, the insertion of the intermediate temporal fascia and of the deep temporal fascia is directly onto the zygoma. In the endoscopic brow lift, the plane of dissection is superficial to the intermediate temporal fascia until just before its insertion onto the zygoma. At this point, the dissection requires division of the intermediate temporal fascia to gain access into the space occupied by the temporal fat pad and, from there, the subperiosteal plane on the zygoma. (From Campiglio GL, Candiani P: Anatomical study on the temporal fascial layers and their relationships with the facial nerve. Aesthetic Plast Surg 1997;21:72.)