The Anatomy of the Temporal and Zygomatic Branches of the Facial Nerve: Application to Crow's Feet Wrinkles

Abstract

Background: Advances in the understanding of wrinkling crow's feet while improving the safety and efficacy of botulinum toxin type A injection has pointed to drug dispersion in the lateral orbital wrinkles as a cause of adverse events of botulinum toxin type A injection. The purpose of this study is to identify the distribution of temporal and zygomatic branches of facial nerve in the orbicularis oculi muscles. Methods: Anatomical dissection of cadavers was performed in 31 cadavers, 13 females and 18 males, with ages ranging from 20 to 60 years, which of all had been embalmed by 10% formalin solution. The facial nerve was identified within subcutaneous tissue close periorbital region and both traced proximal and distal. Its temporal branch, zygomatic branch, facial and muscular entrance were located and accurately measured relative to established surface landmarks. Results: Dissection of the facial nerve revealed 2 to 6 entrances of the temporal branch into the orbicularis oculi and 1 to 5 entrances of the zygomatic branch into the orbicularis oculi. Concerning the measurements of neural entering points, distance and angle from orbicularis oculi muscle to lateral ocular angle, a distribution map of its muscular entrance and their patterns of distribution were constructed. According to the dense area of the coordinate map, there were 3 points determined as the muscular entrance points to established surface landmarks.Conclusions: An anatomical dissection of cadavers was performed to identify the distribution of temporal and zygomatic branches of the facial nerve in the orbicularis oculi. According to the dense area of the coordinate map, the surface landmarks of 3 points were established as the muscular entrance of the facial nerve (MEF).

Heterogeneous crow's feet line patterns and customized botulinum toxin rejuvenating treatment

“…As shown by the favorable outcomes in the two pivotal trials, the procedures described in the current botulinum toxin prescribing information are probably appropriate for most subjects with moderate or severe dynamic CFLs 3 . Yet, the periorbital areas are also those most frequently fraught with adverse botulinum toxin sequelae 16 …”

“…3 Yet, the periorbital areas are also those most frequently fraught with adverse botulinum toxin sequelae. 16 In 2003, Kane identified four main CFL patterns: a "full-fan pattern" (prevalence, 47%) with lateral canthal rhytids extending from the lower lateral brow across the upper eyelid, through the lateral canthus, and across the lower eyelid/upper cheek junction; a "lowerfan pattern" with the crinkling of the lower lid/upper cheek area alone (prevalence, 25%); an "upper-fan pattern" severely affecting the upper lid skin down to the lateral canthus (prevalence, 18%); a "central-fan pattern" or lateral canthus pattern, with rhytids affecting only the skin areas surrounding the lateral canthus (prevalence, 10%). was also variable, with full-fan individuals reaching a zenith of dissatisfaction at maximum smile compared with other CFL patterns.…”

Long-Term Improvement of Crow's Feet Wrinkles in Combination With Cervicofacial and Temporal Lifting

“…5 Detailed anatomy of orbicularis oculi muscle motor innervation has been well documented. 5,14,[16][17][18][19][20][21][22][24][25][26][27][28] The area 6 mm above and 4 mm below the lateral canthal crease is of particular clinical significance; it defines the facial nerve danger zone. The anterior area of the zygomatic arch without muscle coverage is also a danger zone where the facial nerve destined for the lateral pretarsal orbicularis oculi passes.…”

“…Several different patterns of animation have been observed 5 . Detailed anatomy of orbicularis oculi muscle motor innervation has been well documented 5,14,16–22,24–28 . The area 6 mm above and 4 mm below the lateral canthal crease is of particular clinical significance; it defines the facial nerve danger zone.…”

Vascular anatomy of temporal fossa

“…59,60 Further cadaver analyses have identified the distribution of temporal branches of the facial nerve with relation to the orbicularis oculi, showing subbranches commonly sent from the temporal branch into the orbicularis oculi on the zygomatic arch. 61 Specifically, the lowermost subbranch forms a neural plexus with the subbranch of the zygomatic branch prior to entering the orbicularis oculi. In addition, the landmark of three density points was identified in relation to the muscular entrance of the facial nerve of temporal and zygomatic branches (39, 40 and 42mm for the upper, middle, and lower points, respectively).…”