摘要

Objectives: The zygomaticus major muscle demonstrates variable points of origin along the zygomatic arch. These anatomical differences can directly influence vectoring and tissue mobilization during deep plane facelifts. This study aims to present observed variations and their potential impact on outcomes when performing extended deep plane facelifts with subplatysmal release. Introduction: Successful outcomes in deep plane facelift surgery depend heavily on a precise understanding of midfacial anatomy. Among the key structures, the zygomaticus major muscle plays a central role in determining vectoring, flap mobilization, and tension distribution. However, despite its clinical importance, the zygomaticus major demonstrates considerable anatomical variability that can directly influence surgical approach and outcomes. Limited literature has detailed the implications of these variations for deep plane or extended facelift techniques. This study explores the spectrum of zygomaticus Materials / method: Twenty-five hemifaces (4 fresh, 21 preserved cadavers) were dissected in a standardized fashion, tracing the masseteric nerve from its entry at the mandibular notch to terminal branches. Distances from the zygomatic arch to first branching, depth relative to periosteum, and vertical distribution were measured. Clinical implications for injection strategy were analyzed. Results: The masseteric nerve consistently entered at the mandibular notch, branching on average 15 mm below the zygomatic arch, with multiple vertical bands coursing through the muscle. These findings suggest that uniform three-point injection may fail to adequately cover innervation zones. A multi-point, anatomy-guided injection pattern is proposed to optimize outcomes and reduce risks of bulging or incomplete relaxation. Conclusion: The zygomaticus major demonstrates consistent but clinically significant anatomical variation that directly impacts the execution of extended deep plane facelifts with subplatysmal release. Awareness of these patterns allows surgeons to anticipate challenges in flap mobilization, adjust vectoring strategies, and minimize the risk of distortion or suboptimal midface repositioning. Incorporating anatomy-driven modifications enhances both the safety and predictability of outcomes, underscoring the importance of individualized surgical planning based on detailed anatomical understanding.