Facial Plastic and Reconstructive Surgery, North Shore University Hospital, Manhasset, NY.
Division of Facial Plastic and Reconstructive Surgery, Albert Einstein College of Medicine, New York, NY.
Aesthet Surg J. 2020 Mar 23;40(4):351-356. doi: 10.1093/asj/sjz114.
The vector of superficial musculoaponeurotic system (SMAS) redraping in rhytidectomy is often described in relation to the zygomaticus major muscle (ZMM), so that suspension prevents distortion of the mimetic musculature and a "facelifted appearance." There are no data describing the true orientation of this muscle in the midface.
The aim of this study was to define the vector of the ZMM relative to the Frankfort horizontal plane.
One hundred patients underwent deep plane rhytidectomy. As part of this procedure the tissues overlying the ZMM are elevated, allowing muscle orientation to be measured as an angle relative to the Frankfort horizontal plane.
Data for 200 hemifaces were aggregated. The average ZMM angle was 59° (standard deviation, 6°; range, 41-72°) relative to the Frankfort horizontal plane, and showed a statistically significant pattern of change with advancing age, becoming more acute with increasing age below the age of 60 years and more obtuse with age over 60 years.
The native vector of the ZMM varies significantly between rhytidectomy patients as demonstrated by the high variance in this cohort. Assumptions about its orientation should not be made in rhytidectomy techniques that do not identify its course. Standard vectors of SMAS redraping, such as superior-lateral, vertically oblique, and purely vertical, should be reconsidered and a customized vector implemented in each case. Aging affects the orientation of the muscle, which can potentially be explained by soft tissue and bony changes at its attachments. This furthers the variability of the SMAS vector in each individual case.
面部提升术中 SMAS 浅层肌膜系统（SMAS）的重新悬吊通常与颧大肌（ZMM）相关联，从而使悬吊术防止了表情肌的变形和“提升后的外观”。目前尚无关于该肌肉在中面部的确切方向的数据描述。
本研究旨在确定 ZMM 相对于法兰克福水平面的向量。
100 例患者接受了深部平面除皱术。作为该程序的一部分，提升了覆盖在 ZMM 上的组织，从而可以测量肌肉相对于法兰克福水平面的定向作为角度。
汇总了 200 个半面的数据。ZMM 的平均角度为 59°（标准差为 6°；范围为 41-72°）相对于法兰克福水平面，并且随着年龄的增长呈现出统计学上显著的变化模式，在 60 岁以下的年龄，其变得更加锐利，而在 60 岁以上的年龄，其变得更加钝。
正如该队列中较高的方差所表明的那样，ZMM 的固有向量在除皱术患者之间存在显著差异。在不识别其行程的除皱术技术中，不应假设其定向。应该重新考虑 SMAS 重新悬吊的标准向量，例如上外侧、垂直斜向和纯垂直，并在每种情况下实施定制向量。肌肉的定向会受到年龄的影响，这可以通过其附着处的软组织和骨变化来解释。这进一步增加了每个个体案例中 SMAS 向量的可变性。
