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: 1. 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. 2. The frontal branch penetrated the deep fascia to the SMAS at about 0.5 cm below the zygomatic arch. 3. Some buccal branches went through the cheek fat pad while the others lay on its surface directly under the thin SMAS. 4. 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.
Adult Aged