现代面部除皱术的面神经解剖学研究

目的明确ＳＭＡＳ与面神经的关系。方法对１２具（２４侧）成人尸头行大体解剖观察。结果ＳＭＡＳ分布于面中部，向前逐渐变薄，于口角水平外侧有小范围的“洞区”。面神经出腮腺后，并非在ＳＭＡＳ深面，而是在咬肌筋膜深面走行。面神经额支在颧弓以下０５ｃｍ区域穿出深筋膜，跨过颧弓。在颊脂肪垫区，大部分面神经分支走行在垫内，小部分分支形成面神经丛，分布于其表面。在颧大肌表面上１／３恒定有一颧支跨过，支配眼轮匝肌下外侧９例（占３７５％）；颧大、小肌及眼轮匝肌８例（占３３３％）；颧大、小肌７例（占２９２％）。结论面部多层次剥离除皱术应在颧弓以下０５ｃｍ区域行ＳＭＡＳ下剥离，至面中部时，应注意保护颧大肌表面上１／３段的面神经颧支，只在颧大肌中下２／３段区域进行剥离，向内掀起颧脂肪垫；或通过下睑缘皮肤切口，向下掀起眼轮匝肌（注意保护位于颧大肌上１／３段的面神经颧支），与经耳前ＳＭＡＳ下剥离腔隙连通，如上操作可避免面神经损伤。

Anatomical basis for the newly developed facelifting

Objective\ To investigate the relationship between the SMAS and the facial nerve divisions in the cheek area. Method\ We dissected 12 cadaver heads(24 sides). Results\ SMAS distributed over the middle face. It became thinner as it extended forward and there was a small aperture lateral to the mouth. The branches of facial nerve lay directly beneath the parotidomassetric fascia after emerging from the parotid gland.The frontal branch penetrated the deep fascia to the SMAS at about 0.5cm below the zygomatic arch.Some buccal branches went through the cheek fat pad while the others lay on its surface directly under the thin SMAS.There was constantly a zygomatic ramus went into the upper one third of the zygomaticus. It innervated the lower and lateral orbicularis oculi muscle in 9 of 24 sides (37.5%) of the cadaver heads, zygomaticus major and minor and orbicularis oculi muscle in 8 of 24 sides(33.3%), and the zygomaticus major and minor in 7 of 24 sides (29.2%). Conclusion\ During facelifting, wide dissection of the SMAS should be done directly above the parotidomassetric fascia and 0.5 cm below the zygomatic arch. While approaching the middle face, the dissection should be limited to the lower two third of the zygomaticus, followed by elevating the zygomatic fat.The authors dissect the nasolabial fold through the lower eyelid incision, then the dissection should go downwards, under the orbicularis oculi muscle, to the nasolabial area. In a clinical situation, care must be taken not to damage the facial nerve trunk, and dissection of the upper one third of the zygomaticus should be avoided.